York has a large and friendly mathematical physics group with a wide range of research interests and an international outlook, with graduate students and researchers from many countries choosing to work here. If you are interested in graduate study or postdoctoral research, please contact the relevant member of staff.
The main areas of research are Quantum Gravity, Quantum Field Theory and Integrable Models, Quantum Information and Foundations of Quantum Mechanics, and Quantum Groups.
Information about the staff members and research fellows, graduate students and visitors in our group.
The group has two seminars every week. These are very lively with many questions and active participation by the graduate students.
You will find links to recent publications of the group from these pages.
Scientists that have visited our group at York.
We invite you to join our group as a graduate student.
We participate in, and help organize, various series of research meetings, including NBMPS, BritGrav and ICFT.
Dr Henning Bostelmann Dipl. Phys., Dr. rer. nat. (Göttingen); Master of Computer Science (Hagen) Algebraic quantum field theory, operator algebras +44 1904 32 3088 henning.bostelmann@york.ac.uk 

Professor Paul Busch Dipl.Phys.(MSc, Cologne), Dr.rer.nat.(Cologne) Quantum mechanics, foundations, quantum measurement and information, quantum theory and relativity. +44 1904 32 3082 paul.busch@york.ac.uk 

Dr Roger Colbeck PhD (Cambridge) quantum information theory, foundations of quantum mechanics +44 1904 32 3093 roger.colbeck@york.ac.uk 

Professor Ed Corrigan MA, PhD (Cantab), FRS Quantum field theory, integrable systems, solitons, defects +44 1904 32 3074 edward.corrigan@york.ac.uk 

Dr PierrePhilippe Dechant BA/MA (Cantab), CASM/MMath (Cantab), PhD (Cantab) Symmetries, Viruses; Group theory, Coxeter groups, Lie algebras, Clifford algebras, gravitational and particle physics, Moonshine +44 1904 32 5370 pd583@york.ac.uk 

Dr Gustav W Delius PhD (Stony Brook) Stochastic Modelling in Mathematical Biology and Theoretical Ecology, Spatial Stochastic Processes, Quantum Field Theory, Integrable Systems, Quantum Groups +44 1904 32 3077 gustav.delius@york.ac.uk 

Professor Chris Fewster MA, PhD (Cantab) Mathematical issues in quantum and gravitational physics. Quantum field theory in curved spacetime. Algebraic quantum field theory. +44 1904 32 3091 chris.fewster@york.ac.uk 

Dr Markus B Fröb Dipl.Phys. (FSU Jena), Dr. (UB Barcelona) quantum field theory, quantum gravity +44 1904 32 3081 mbf503@york.ac.uk 

Dr Eli Hawkins PhD (Penn State, Physics), PhD (Penn State, Mathematics) +44 1904 32 3069 eh555@york.ac.uk 

Dr Atsushi Higuchi BSc (Tokyo), MSc (Kyoto), PhD (Yale) Quantum field theory, general relativity. +44 1904 32 3089 atsushi.higuchi@york.ac.uk 

Professor Bernard S. Kay MA (Cantab), PhD (London) quantum fields, quantum gravity, fundamental problems in quantum theory +44 1904 32 3092 bernard.kay@york.ac.uk 

Prof. Niall MacKay BA (Cambridge), PhD (Durham) Integrable quantum field theory, quantum groups +44 1904 32 3493 niall.mackay@york.ac.uk 

Dr Sammy Ragy MPhys (University of St Andrews), PhD (University of Nottingham) Quantum information, quantum optics, quantum metrology, quantum correlations +44 1904 32 3079 sammy.ragy@york.ac.uk 

Vidas Regelskis PhD (York), MSc (Vilnius, Lithuania) Yangians and KacMoody Lie algebras, Representation theory, Integrable systems +44 1904 32 3079 vidas.regelskis@york.ac.uk 

Dr Kasia Rejzner mathematical structures relevant for quantum field theory +44 1904 32 4153 kasia.rejzner@york.ac.uk 

Professor Evgeny Sklyanin MSc, PhD (Steklov Institute, St Petersburg), FRS Quantum and classical integrable systems, quantum groups +44 1904 32 4162 eks2@york.ac.uk 

Professor Reidun Twarock MSc (Bath), PhD (Clausthal, Germany) Mathematical Biology, Mathematical Physics +44 1904 32 5368 rt507@york.ac.uk 

Dr Stefan Weigert PD Dr (Basel/CH) quantum foundations and quantum information: mutually unbiased bases, quantum state reconstruction; PTsymmetry +44 1904 32 4152 stefan.weigert@york.ac.uk 
Name  Degree information  Phone  

Peter Brown  MMath (York)  +44 1904 32 XXXX  pjb519@york.ac.uk 
Alejandro De La Rosa Gomez  BSc (Wisconsin), MSc (Imperial)  +44 1904 32 3845  alrg500@york.ac.uk 
Daniel Hills  MMath (York)  +44 1904 32 3075  dh579@york.ac.uk 
Spiros Kechrimparis  BSc, MSc (Patras)  +44 1904 32 3844  sk864@york.ac.uk 
Callum King  MPhys (Sussex)  +44 1904 32 XXXX  crck500@york.ac.uk 
Michael Kiss  MPhys (Soton), MASt (Cantab)  +44 1904 32 XXXX  mk1083@york.ac.uk 
Umberto Lupo  BSc (Warwick), MASt (Cantab)  +44 1904 32 3075  ul504@york.ac.uk 
Robert Parini  MSci (Dunelm)  +44 1904 32 n/a  rp910@york.ac.uk 
Oliver ReardonSmith  MSci in Mathematics and Physics (Bristol)  +44 1904 32 XXXX  ors510@york.ac.uk 
Nicola Rendell  MSci (Dunelm)  +44 1904 32 XXXX  nlr512@york.ac.uk 
Mirjam Weilenmann  BSc & MSc (ETH, Zurich)  +44 1904 32 n/a  msw518@york.ac.uk 
Francis Wingham  MSci (Nottingham)  +44 1904 32 4586  flw508@york.ac.uk 
Vicky Wright  MMath (York)  +44 1904 32 XXXX  vw550@york.ac.uk 
Neil Stevens, PhD 2015 Johannes Biniok, PhD 2015 Dan McNulty, PhD 2013 Matthew Ferguson, PhD 2013 David Hunt, PhD 2013 Leon Loveridge, PhD 2013 Vidas Regelskis, PhD 2013 David Bullock, PhD 2012 Leonardo Ortiz, PhD 2012 Faisal Mir, PhD 2011 Charlie Dyson, MSc 2011 Paul Melvin, PhD 2010 Stephen Brierley, PhD 2010 YenCheong Lee, PhD 2010 Jacobus Sanders, PhD 2009 Joseph Hilling, M.Phil. 2009 Paul Butterley, PhD 2008 William Hall, PhD 2008 Peter Larkin, PhD 2008 Lutz Osterbrink, PhD 2008 Sikarin YooKong, MSc 2008 Ko Sanders, PhD 2008 Giles Martin, PhD 2007 Lieven Clarisse, PhD 2006 David Emms, PhD 2006 Barry Miller, PhD 2006 Calvin Smith, PhD 2006 Varqa Abyaneh, PhD 2005 Joseph Hilling, PhD 2005 Emily King, M.Phil. 2005 Simon Dawson, PhD 2004 Alan George, PhD 2004 Cristina Zambon, PhD 2004 Richard Weeks, PhD 2004 Ukyo Kono, MSc 2004 Jason Szulc, PhD 2003 Ben Short, PhD 2003 Brett Gibson, PhD 2001 Spyros Kouris, PhD 2001 Chris Barton, PhD 2000 Hilary Carteret, PhD 2000 Stefan Hollands, PhD 2000 Alfredo CalvoPereira, MSc 2000 
This page lists past members of the Mathematical Physics group who have left since summer 2000.
Our research subdivides into four main areas, with many overlaps.
Quantum GravityStaff: H Bostelmann, C Fewster, A Higuchi, B Kay, E Hawkins, K Rejzner; 

Quantum IntegrabilityStaff: E Corrigan FRS; G Delius; N MacKay; E Sklyanin FRS; 

Quantum Information & FoundationsStaff: P Busch, R Colbeck, C Fewster, A Higuchi, B Kay, S Ragy, A Sudbery, S Weigert; 

Quantum GroupsStaff: GW Delius, N MacKay, M Nazarov, E Sklyanin FRS, S Donkin, A Sudbery 
For other research areas in physics please visit the research pages of the Department of Physics.
The quantum gravity group carries out research on various aspects of quantum gravity as well as on some allied areas of mathematical physics, including certain topics in quantum mechanics and also in classical general relativity. A particular interest of the research group is the subject of quantum field theory in curved spacetime. Our work often makes use of rigorous techniques drawn from functional analysis (e.g. the theory of operators on Hilbert spaces and operator algebras) and other areas of pure mathematics including differential geometry, microlocal analysis and category theory.
While a satisfactory theory of full quantum gravity continues to elude us, the attempt to anticipate some of the properties of such a theory has led to many interesting developments. Especially, Hawking's 1974 prediction of black hole evaporation, which was based on consideration of quantum field theory in curved spacetime, suggests that there must be yettobediscovered deep interconnections between quantum theory, gravity and thermodynamics. More generally, the very existence of the problem of quantum gravity has changed our perspective on each of the separate theories of classical general relativity and quantum field theory and focussed attention on issues (e.g. the problem of singularities in classical general relativity or the problem of locality in quantum field theory) which might be expected to be of relevance for the unification problem. Further, both at the theoretical and experimental/observational level, the two subject areas have now essentially merged, with veryhighenergy phenomena believed to have dominated the era just after the big bang and hence to have determined the present structure of the universe.
Recent research by the York group concerns the following issues:
Most forms of classical matter have a positive energy density, a fact closely related to our experience of gravity as an attractive force. However, the situation is very different in quantum field theory, where the energy density can typically be made as negative as we like. Recent work by Fewster has been directed towards developing "quantum energy inequalities" for quantum fields which show (roughly speaking) that the magnitude and duration of negative energy densities are constrained: the energy density cannot be too negative for too long. An introduction to QEIs and some of the related techniques can be found in Fewster's lecture notes.
Higuchi, with students Kouris and Weeks, has shown that the growth at long distance of the graviton twopoint function in an inflationary spacetime is not reflected in physical twopoint functions. He is currently examining claims in the literature that the cosmological constant would be suppressed in such spacetimes due to the abovementioned growth of the graviton twopoint function. See grqc/0212031 and references therein. In related work, Fewster and his student Hunt have studied the quantisation of linearised gravity in general cosmological vacuum spacetimes  see arXiv:1203.0261.
In Minkowski space there is an obvious natural vacuum state for quantum field theory picked out by Poincare invariance. General spacetimes do not have any symmetries and therefore no single natural vacuum state. Instead, a class of physical states is indentified (the Hadamard class). The first fully precise definition of the Hadamard condition was given by Kay and Wald in 1991; not long after that, Radzikowski showed that this condition could be reformulated in terms of microlocal analysis. Work by the York group has extended and refined this formulation; in particular, it plays an important role in Fewster's work on quantum inequalities and was used by Kay in work (with Radzikowski and Wald) on time machine spacetimes (see below). Recently, Fewster and Verch have given a new motivation for the Hadamard class: at least in ultrastatic spacetimes, they showed that any state in which the associated Wick polynomials have finite fluctuations is necessarily Hadamard see arXiv:1307.5242.
Quantum field theory in Minkowski space depends in many ways on the high degree of spacetime symmetry. General curved spacetimes lack any symmetry at all, which makes it hard to prove general statements about general quantum field theories (as opposed to specific models). A major development was the introduction by Brunetti, Fredenhagen and Verch of a locally covariant formulation of QFT in CST based on techniques of category theory. The basic idea is that a theory can be described by a functor from a category of spacetimes to a category of physical systems. Fewster, and his students Lang, Ferguson and Sanders, have worked on various aspects of this formalism, including the formulation of the Dirac theory and a proof of a ReehSchlieder theorem (Sanders) and the analysis of when a theory can be thought to describe the same physics in all spacetimes (Fewster [with Verch], Ferguson) as well as studying the effect of spacetime topology on locally covariant theories (Fewster and Lang). Fewster has also shown how the global gauge group of a locally covariant theory can be identified with the automorphism group of the corresponding functor (arXiv:1201.3295). Moreover, a nice consequence of Fewster and Verch's work is a general proof that quantum field theories in curved spacetime do not have natural states, something which had been a "folk theorem" for many years (arXiv:1106.4785).
General relativity may be regarded as a constrained dynamical system. Although there is a standard method for quantizing constrained systems, due to Dirac, there are obstacles to applying this method to general relativity. There has been a claim that these obstacles can be overcome, and Higuchi is currently trying to determine whether or not this claim is justified.
Higuchi has studied a model in quantum field theory in which one can consider the radiation reaction to a charged particle and then take the classical limit. He found that the result agrees with the standard LorentzDirac theory (quantph/0208017). He is currently attempting to compare the radiation reaction in the LorentzDirac theory and that in the quantum theory of a more realistic model.
Kay is presently continuing to work, partly together with Varqa Abyaneh, on a theory (see hepth/9810077) according to which it is the entanglement between the quantum gravitational field and the quantum state of macroscopic quantum systems which is ultimately responsible for those systems being (with some probability distribution) in one or other of a number of definite spatial configurations. In particular, in the case of Schrodinger's cat this theory offers an explanation as to why the cat has to be either dead or alive.
In the past, other issues investigated by the York group have included:
In the early 1990s, Kay was involved in proving mathematical theorems which improved our understanding of why it is that  as discovered by Stephen Hawking in 1974  black holes have to be hot.
Work by the York group has contributed to the present understanding that time machines cannot be manufactured. In particular, Kay has been involved in proving rigorous mathematical theorems (see, e.g., grqc/9603012 and grqc/9708028) which may be interpreted as telling us that it is impossible to manufacture a time machine which would allow travel to the past by warping spacetime in a way which is describable in terms of the traditional notions of spacetime geometry familiar from Einstein's classical theory of general relativity. These theorems thus tend to lend support to Stephen Hawking's Chronology Protection Conjecture although they don't exclude the possibility of time machines which are so exotic that they warp spacetime in ways which are not describable in classical terms. For a recent overview of the work by Kay mentioned above see grqc/0103056.
Other work by the York group has studied the properties of quantum systems on spacetimes containing time machines (setting aside the question of whether such a thing could be manufactured). Kay proposed a weakening of the usual formulation of quantum field theory for such situations; this was further investigated by Fewster and Higuchi (grqc/9508051) and then Fewster (grqc/9804012). This led to the conclusion that  at least in two dimensions  the proposed framework could not be implemented on generic time machine spacetimes. Other work conducted by Fewster, Higuchi and Wells (grqc/9603045) also supports the view that quantum theory (at least as presently understood) cannot generally be formulated in the presence of time machines.
Higuchi showed that the absorption cross section by a black hole (of arbitrary spacetime dimension) of any kind of massless scalar particle is exactly equal to the horizon area (hepth/0108144). He also investigated how a charge just outside a black hole responds to Hawking radiation (see grqc/0011070 and references therein).
Ed Corrigan, Gustav Delius, Niall MacKay, Evgeny Sklyanin, Vidas Regelskis
Integrable models are systems in quantum physics which can be solved exactly, because they have a large number of conserved quantities and thus a high degree of symmetry. They appear in many guises  field theories, spin chains, models of statistical mechanics, models of a fixed number of interacting particles  and can also be subsumed into models with even more symmetry, such as conformal field theories and 'superintegrable' models (such as Newtonian gravity and the hydrogen atom!).
The last few decades have seen a resurgence of exactlysolvable physical systems, which appear ubiquitously in modern fundamental physics. For example, they have been at the heart of recent advances in our understanding of the relationship between gauge field theory and string theory, and one of us (Niall MacKay) was an organizer of the research programme on 'Strong Fields, Integrability and Strings' at the Newton Institute, Cambridge in 2007. The mathematical beauty of such models is often seen in new algebraic structures (usually 'quantum groups'), and we have been involved in the discovery and development of many of these.
In our research we typically use classical and firstorder quantum ('semiclassical') methods, and try to mesh these together with algebraic techniques which can give exact (to all orders in Planck's constant) results. This gives us a window into many nonperturbative phenomena, such as
To study these we use extended symmetries and principles like
Besides their utility in unravelling the nonperturbative structure of twodimensional quantum field theories these symmetry principles fascinate us because of their intrinsic mathematical beauty. Particular examples of fruitful models are
Quantum Foundations research aims at understanding the puzzling features of quantum theory such as: indeterminacy; the incompatibility of pairs of physical quantities (aka complementarity); the fact that measurements necessarily affect the observed system (aka Heisenberg effect); the strange way in which quantum systems are correlated (aka entanglement); and quantum nonlocality. As well as marking the contrast between quantum and classical physical theories, these features have been found to constitute potentially powerful resources for information processing, thus giving rise to the novel and rapidly developing field of Quantum Information Science, where new paradigms of computation, communication and cryptography are being explored.
Research in the quantum information and foundations group focuses on structural aspects of quantum theory that are relevant to quantum information. Current research themes include:
Our group maintains interactions with researchers in the Physics and Computer Science Departments through the Quantum Information Seminar held weekly in term time. Within York, this involves the following researchers as part of the York Centre for Quantum Technologies:
Regional cooperations are facilitated through the White Rose Universities Consortium which sponsors regular quantum information meetings in Leeds, Sheffield and York. International collaborations include the Operational Quantum Physics group at the University of Turku.
News: For current job opportunities see here.
For information about possible PhD projects, see here.
The Mathematics department at the University of York would like to encourage and support applicants who wish to apply for an EPSRCfunded 5 year quantum technologies fellowship based in York. These are available at both the 'early career' and 'established career' stages. Within the department Paul Busch, Roger Colbeck and Stefan Weigert are pursuing research in quantum information and there is further expertise in York in the Physics and Computer Science departments, which are all part of a newly established Centre for Quantum Technologies. More information about our staff and research can be found at
http://maths.york.ac.uk/www/PhysicsComputing
While we are open to applications for any area relevant to the call, we would particularly welcome those whose research interests include quantum key distribution, quantum randomness generation, quantum metrology or related topics.
There are two deadlines for submission of fellowship proposals and fixed start dates:
* 16:00 on 30 October 2014 [Fixed start date of 01 April 2015]
* 16:00 on 29 January 2015 [Fixed start date of 01 July 2015]
Note that certain eligibility criteria apply, further details of which can be found at
http://www.epsrc.ac.uk/skills/fellows/quantumtechnology/
If you are interested in this opportunity, please make contact with one of us as soon as possible, and at least 1 month before either deadline.
Continuous ('Lie') groups, such as the unitary and orthogonal groups, have been at the heart of the development and classification of new models of particle physics. But at the end of the 1970s hints appeared that, at least in some simple models, there were more subtle algebraic structures, based on Lie groups but deformed in some way dependent on Planck's constant: hence 'quantum' groups. These were set on firm mathematical foundations in the 1980s by Jimbo and by Drinfeld, who later won the Fields medal for this and other work.
Quantum groups appear in many ways in mathematical physics, and especially in integrable models, both of field theory and of statistical mechanics, where they describe various sets of conserved quantities (in an extension of the ideas of spin and isospin), and also appear as purely ('auxiliary') algebraic structures.
Research at York covers this full spectrum, from the construction of quantum groups in terms of fields and physical observables through to a mathematical examination of their structure and representations.
The seminars take place on Tuesday lunchtimes at 2:00 pm (mostly internal speakers) and Thursday afternoons from 4:15 pm (mostly external speakers, and preceded by coffee/tea from 4pm), in the relaxed atmosphere of Room G/109 in James College Nucleus. The typical length of the talks is about 1 hour.
Information on How to Reach the University is available. You can locate James College on the campus map. Please contact Eli Hawkins by email if you need further information.
Please also check the Upcoming Events page for other seminars which might be of interest. For example the Departmental Colloquium talks on Wednesdays sometimes are on mathematical physics.
Date and time  Title  Speaker  Room 

April 14, 2016, 16:15  17:30  Vacuum for a massless quantum scalar field outside a collapsing shell in antide Sitter spacetime  Paul Abel (Leicester)  G/109 
April 21, 2016, 16:15  17:30  Compact forms of the RuijsenaarsSchneider system  László Fehér (Szeged)  G/109 
May 5, 2016, 16:15  17:30  Integrable boundary scattering in AdS3/CFT2 correspondences  Andrea Prinsloo (Surrey)  G/109 
May 12, 2016, 16:15  17:30  How to measure black holes: numerical relativity and gravitational waves  Mark Hannam (Cardiff)  G/109 
May 19, 2016, 16:15  17:30  Boundary quantum KZ equations  Bart Vlaar (Nottingham)  G/109 
May 31, 2016, 14:00  15:00  Quantum Particle Creation by Gravitational Fields  Larry Ford (Tufts)  G/109 
June 7, 2016, 14:00  15:00  Defending and Extending the Unruh Effect  Marek Radzikowski (American University of Afghanistan)  G/109 
June 9, 2016, 16:15  17:30  Superconformal ChernSimons Matter Theory in Lorentzian Curved Manifolds  Mojtaba Taslimit (Leipzig)  G/109 
June 14, 2016, 14:00  15:00  Generalised Hyperbolicity  Yafet Sanchez Sanchez (Southampton)  G/109 
June 16, 2016, 16:15  17:30  Hydrodynamic simulations of rotating and nonrotating black holes  Silke Weinfurtner (Nottingham)  G/109 
June 30, 2016, 16:15  17:30  Signatures of Relic Quantum Nonequilibrium  Nick Underwood (Clemson)  G/109 
July 14, 2016, 16:15  17:30  TBA  Eleni Kontou (Bard College)  G/109 
July 20, 2016, 16:15  17:30  Small scale structure of spacetime  Dawood Kothawala (IIT Madras)  G/109 
Please note that this is an evolving programme. It is advisable to (reload and) recheck the page shortly before each talk. There is a mailing list for the seminar announcements. For further details please contact Eli Hawkins.
Archive of past Mathematical Physics Seminars: 19992007, 2007today.
See the navigation menu on the lefthand side.
The seminar takes place on Mondays and Thursdays: from 4:20 pm onwards in the very relaxed atmosphere of Room G/109 in Goodricke College. The seminars are preceded by tea from 4 pm. The typical length of the talks is about 1 hour.
All lectures will take place in B/B006 (Biology). The provisional program is below. For more details, see http://winstanley.staff.shef.ac.uk/LEQG.html
All are welcome to attend, but if you plan to attend, please send an email to leqg.york@googlemail.com
Programme:
LowEnergy Quantum Gravity,
University of York, 19th20th July 2007, Biology Lecture Theatre B/B006
Thursday 19th July
2.00  3.15 pm David Toms (Newcastle)
Quantum gravity and gauge coupling constants
3.15  3.45 pm Tea and coffee
3.45  4.25 pm Calvin Smith (Dublin)
Bounds on negative energy in quantum field theory
4.25  4.55 pm Jorma Louko (Nottingham)
How often does an accelerated particle detector click?
4.55  5.35 pm Jean Alexandre (KCL)
A nonperturbative timedependent string configuration without extra dimensions?
Friday 20th July
9.30  10.45 am KarlHenning Rehren (Gottingen)
AdSCFT correspondence and CFT with boundaries
10.45  11.15 am Tea and coffee
11.15 am  12.30 pm Remo Garattini (Bergamo)
A multi gravity approach to spacetime foam
12.30  2.00 pm Lunch
2.00  2.40 pm Veronika Hubeny (Durham)
Emergence of spacetime in AdS/CFT
2.40  3.20 pm Atsushi Higuchi (York)
Infrared properties of quantum field theories in de Sitter spacetime
3.20 pm Tea and coffee
The seminar takes place on Mondays and Thursdays: from 4:20 pm onwards in the very relaxed atmosphere of Room G/109 in Goodricke College. The seminars are preceded by tea from 4 pm. The typical length of the talks is about 1 hour.
Please note that this is the tentative evolving program. It is advisable to (reload and) recheck the page shortly before each talk. There is a mailing list for the seminar announcements. For further details please contact Boris Noyvert.
The seminar takes place on Mondays and Thursdays: from 4:20 pm onwards in the very relaxed atmosphere of Room G/109 in Goodricke College. The seminars are preceded by tea from 4 pm. The typical length of the talks is about 1 hour.
The seminar takes place on Mondays and Thursdays: from 4:20 pm onwards in the very relaxed atmosphere of Room G/109 in Goodricke College. The seminars are preceded by tea from 4 pm. The typical length of the talks is about 1 hour.
Information on How to Reach the University is available. Goodricke College is building 24 on the campus map. Please contact Charles Young by email if you need further information.
Please also check the Departmental Events Calendar for other seminars which might be of interest. For example the Departmental Colloquium talks on Wednesdays sometimes are on mathematical physics.
Mon 13 March at 16:20:
Valya Khoze (Durham)
New results in the betadeformed conformal N=4 SYM: Perturbative Amplitudes, AdS/CFT Correspondence...
The seminar takes place on Mondays and Thursdays: from 4:20 pm onwards in the very relaxed atmosphere of Room G/109 in Goodricke College. The seminars are preceded by tea from 4 pm. The typical length of the talks is about 1 hour. Information on How to Reach the University is available. Goodricke College is building 24 on the campus map. Please contact Charles Young by email if you need further information. Please also check the Departmental Events Calendar for other seminars which might be of interest. For example the Departmental Colloquium talks on Wednesdays sometimes are on mathematical physics. ProgrammePlease note that this is the tentative evolving program. It is advisable to (reload and) recheck the page shortly before each talk. There is a mailing list for the seminar announcements. For further details please contact Charles Young  
20th October 2005 Thursday 4.20pm  David Kagan (DAMTP, Cambridge) Supersymmetric Quantum Mechanics: Central Extensions and Extra Dimensions  
24th October 2005 Monday 4.20pm  Masashi Hamanaka (Nagoya University) Towards Noncommutative Integrable Systems and Soliton Theories  
27th October 2005 Thursday 4.20pm  Thomas Quella (Kings College, London) Supergroup sigmamodels and strings in RR backgrounds  
31st October 2005 Monday 4.20pm  Mathematical Physics Group Meeting  
3rd November 2005 Thursday 4.20pm  Calvin Smith (York) TBA  
7th November 2005 Monday 4.20pm  Bernard Kay (York) Quantum Field Theory in Curved Spacetime  
10th November 2005 Thursday 4.20pm  Terry Rudolph (Imperial) How good must single photon sources be for optical quantum computation?› + Loss tolerant cluster state computation›  
14th November 2005 Monday 4.20pm  
17th November 2005 Thursday 4.20pm  David Olive (Swansea) Minimal representations and Freudenthal Triple Systems  
21st November 2005 Monday 4.20pm  
24th November 2005 Thursday 4.20pm  Valentina Riva (Oxford) New perspective on critical phenomena: SLE and its connection with CFT.  
28th November 2005 Monday 4.20pm  Ruth Williams (DAMTP, Cambridge) Discrete Quantum Gravity  
1st December 2005 Thursday 4.20pm  Gaetano Bertoldi (Swansea) Large N doublescaling limits of 4d gauge theories  
5th December 2005 Monday 4.20pm  
8th December 2005 Thursday 4.20pm  Jonathan Halliwell (Imperial) Emergent Classicality via Commuting Position and Momentum Operators  
12th December 2005 Monday 4.20pm  
15th December 2005 Thursday 4.20pm  Lutz Osterbrink (York) Energy inequalities for the nonminimally coupled scalar field  
19th December 2005 Monday 4.20pm  Yann Golanski (York) Dark energy: Who would have thought Einstein was right? 
See also our Archive of Past Mathematical Physics Seminars
Information on How to Reach the University is available. Goodricke College is building 24 on the campus map. Please contact Bernard Kay by email if you need further information.
28th April 2005 Thursday 4.20pm V/123  Christian Micheletti (SISSA, Trieste) Elastic properties of proteins: characterization of the flexibility of proteins and of their functional movements Note unusual venue: VANBRUGH V/123 
9th May 2005 Monday 4.20pm  I.V. Komarov (St. Petersburg) Poisson maps and Lax pairs for the so(4) Kowalevski top 
16th May 2005 Monday 4.20pm  Anne C. Davis (DAMTP, Cambridge) Exploring Extra Dimensions Through Cosmology 
23rd May 2005 Monday 4.20pm  Tobias Osborne (Bristol) General Monogamy Inequality for Bipartite Qubit Entanglement 
30th May 2005 Monday 4.20pm  Atsushi Higuchi (York) Asymptotic Freedom (Instructional Lecture) 
6th June 2005 Monday 4.20pm  Dajun Zhang (Shanghai) Solutions in Wronskian form to soliton equations 
13th June 2005 Monday 4.20pm  Paul Sutcliffe (Kent) SchrodingerChernSimons vortex dynamics 
28th June 2005 Tuesday (11.45am to 6pm)  Note: Five Mathematical Physics Seminars in the North British Mathematical Physics Seminar today 
30th August 2005 Tuesday 4.20pm  Dmitri Lebedev (ITEP, Moscow) On a class of Representations of Quantum groups and Moduli space of Monopoles I 
2nd September 2005 Friday 11.30am  Dmitri Lebedev (ITEP, Moscow) On a class of Representations of Quantum groups and Moduli space of Monopoles II 
Information on How to Reach the University is available. Goodricke College is building 24 on the campus map. Please contact Bernard Kay by email if you need further information.
Please also check the Departmental Events Calendar for other seminars which might be of interest. For example the Departmental Colloquium talks on Wednesdays sometimes are on mathematical physics.
17th January 2005 Monday 4.20pm  Vincent Caudrelier (LAPTH, Annecy) Impurity in integrable systems: tools, examples and physical consequences 
20th January 2005 Thursday 4.20pm  Andrei Mudrov (MPI, Bonn) Explicit equivariant quantization of semisimple conjugacy classes of simple matrix groups 
27th January 2005 Thursday 4.20pm  Nicola Pinamonti (Trento, Italy) Conformal symmetry breaking on Killing horizons 
31st January 2005 Monday 4.20pm  Jorma Louko (Nottingham) Spin and charges: Weapons of mass construction 
10th February 2005 Thursday 4.20pm  Zoltan Nagy (CergyPontoise) Construction of commuting traces and spin chains using dynamical quadratic algebras 
17th February 2005 Thursday 4.20pm  Matthias Christandl (CQG, Cambridge) Uncertainty, monogamy, and implications for entanglement 
21st February 2005 Monday 4.20pm  Ian Hinder (Southampton) Stability in numerical relativity 
24th February 2005 Thursday 4.20pm  Nilanjana Datta (CQG, Cambridge) Perfect state transfer in quantum spin networks 
28th February 2005 Monday 4.20pm  Jie Xiao (Tsinghua University, Beijing) Quiver representations, RingelHall algebras and quantum groups 
7th March 2005 Monday 4.20pm  Graeme Mitchison (CQG, Cambridge) The spectra of quantum states and their marginals: a group representation perspective 
10th March 2005 Thursday 4.20pm  Veronique Hussin (CRM, Montreal) Degeneracies of the energy spectrum of the JaynesCummings model and coherent states 
14th March 2005 Monday 4.20pm  Valentina Riva (Oxford) Semiclassical methods in 2D QFT: spectra and finitesize effects 
Stability in Numerical Relativity
by Ian Hinder (Southampton)
When solving the Einstein equations numerically, much emphasis is placed on the stability of the numerical scheme. For formulations of the time evolution equations which are second order in space, special care has to be taken in the definition of stability. I review our recent work in this area, as well as notions of wellposedness for the associated second order in space PDE systems.
The spectra of quantum states and their marginals: a group representation perspective.
by Graeme Mitchison (CQG, Cambridge)
I shall describe joint work with Matthias Christandl in which we investigated the "quantum marginal problem". Imagine that one is given a bipartite quantum state (a density matrix rho_AB). By tracing out each party, one obtains two marginal states (density matrices rho_A and rho_B). The spectra of the original state and its two marginals consitute a special triple, and we found a way to characterize such triples in terms of representations of the symmetric group.
Construction of commuting traces and spin chains using dynamical quadratic algebras.
by Zoltan Nagy (CergyPointoise)
I will talk about dynamical extensions of quadratic quantum exchange algebras introduced by Freidel and Maillet and discuss their fusion and comodule structures. I will then show how these structures allow for building of commuting traces and spin chain type hamiltonians.
Information on How to Reach the University is available. Goodricke College is building 24 on the campus map. Please contact Bernard Kay by email if you need further information.
Please also check the Departmental Events Calendar for other seminars which might be of interest. For example the Departmental Colloquium talks on Wednesdays sometimes are on mathematical physics.
18th October Monday 4.20pm  Mathematical Physics Group Meeting 
25th October Monday 4.20pm  Martin Speight (Leeds) Algebraic topology of the Skyrme configuration space 
28th October Thursday 4.20pm  Minitalks by Atsushi Higuchi, Barry Miller and Charles Young (York) 
1st November Monday 4.20pm  Minitalks by Calvin Smith, Giles Martin, and Varqa Abyaneh (York) 
11th November Thursday 4.20pm  Simon Ross (Durham) Timedependent spacetimes in AdS/CFT 
15th November Monday 4.20pm  Nick Evans (Southampton) A gravitational dual description of chiral symmetry breaking 
22nd November Monday 4.20pm  Roberto Casadio (Bologna) Improved WKB analysis of cosmological perturbations 
25 November Thursday 4.20pm  Richard Szabo (Heriot Watt) 2D YangMills theory and moduli spaces of holomorphic differentials 
2nd December Thursday 4.20pm  Nicolas Crampe' (York) Closed and open spin chain in any representation 
6th December Monday 4.20pm  Ron King (Southampton) Local equivalence of twoqubit states: a problem in invariant theory 
13th December Monday 4.20pm  Robert Weston (Heriot Watt) Transmitting defects in solvable lattice models 
Improved WKB analysis of cosmological perturbations
by Roberto Casadio (Bologna)
I present improved WKBtype approximations in order to study cosmological perturbations beyond the lowest order. The methods are based on functions which approximate the true perturbation modes over the complete range of the independent variable, including the turning point, and employ both a perturbative Green's function technique and an adiabatic expansion in order to compute higher order corrections. The methods are tested on the benchmark of powerlaw inflation: the nexttoleading order adiabatic expansion yields the amplitude of the power spectra with excellent accuracy, whereas the nexttoleading order with the perturbative Green's function method does not improve the leading order result significantly. In more general cases, either or both methods may be useful.
Local equivalence of twoqubit states: a problem in invariant theory
by Ron King (Southampton)
Twoqubit states can be described in terms of a density matrix. To classify states up to local equivalence it is necessary to study invariants that are polynomial in the density matrix parameters. Here we tackle the problem of not just counting the number of linearly independent polynomial invariants of given degree, but also identifying a suitable basis that can be used to generate them all quite explicitly. This is a classical invariant theory problem involving the group U(16) and its restriction to a particular subgroup U(2)xU(2). A complete solution is provided, including en route a few surprises and some interesting syzygies.
Information on How to Reach the University is available. Goodricke College is building 24 on the campus map. Please contact Bernard Kay by email if you need further information.
Please also check the Departmental Events Calendar for other seminars which might be of interest. For example the Departmental Colloquium talks on Wednesdays sometimes are on mathematical physics.
19 April Monday 4.20pm  Yvette FuentesGuridi (Oxford) Holonomic quantum computation in the presence of decoherence 
26th April Monday 4.20pm  Ed Copeland (Sussex) Trying to understand the nature of dark energy in the Universe 
13th May Thursday afternoon  No Seminar But ... There are some interesting MMath presentations 
17th May Monday 4.20pm  Alan George (York) Coupling the massive KleinGordon field to a boundary oscillator 
20th May Thursday 4.20pm  Andreas Winter (Bristol) Generic aspects of quantum entanglement 
24th May Monday 4.20pm  Alan George (York) Coupling the massive KleinGordon field to a boundary oscillator (continued) 
27th May Thursday 4.20pm  Gabor Toth (Eotvos University, Budapest) On N=1 supersymmetric boundary bootstrap 
17th June Thursday 4.20pm  Stefan Antusch (Southampton) Neutrino Mass Models 
28 June Monday 4.20pm  Zoltan Bajnok (Eotvos University, Budapest) Semiclassical SineGordon on the strip 
Holonomic quantum computation in the presence of decoherence
by Yvette FuentesGuridi (Oxford)
We investigate the effects of decoherence in the geometric evolution of states of a degenerate quantum system. This is done by generalizing the scheme for geometric phases in open systems to nonAbelian holonomies. The formalism is applied to estimate the errors produced by performing an universal set of holonomic quantum gates in the presence of an environment. We pinpoint the source of error in the scheme that must be corrected to achieve holonomic quantum computation completely robust to decoherence.
Generic aspects of quantum entanglement
by Andreas Winter (Bristol)
Probability theory has some insight to offer into the typical behaviour of states on large composite quantum systems. For example, because they are of measure zero in state space, product states are "never" seen when drawing a pure state uniformly at random. It may already come as a surprise that for large local dimension in a bipartite system the overwhelming majority of all pure states is in fact close to maximally entangled.
But even more is true: random subspaces of close to full dimension will with overwhelming probability contain only almost maximally entangled states. This implies that under a certain natural probability measure the generic mixed state will have almost maximal entanglement of formation. On the other hand, the distillability properties of these states can be shown to be very poor, both for EPR pairs and for secret key.
The techniques carry over to multiparty states, and offer a vision of "generic entanglement" as highly irreversible but potentially quite uniform  in contrast to the bewildering array of different types of entanglement in an exact classification. This is joint work with Patrick Hayden and Debbie Leung (Caltech).
Information on How to Reach the University is available. Goodricke College is building 24 on the campus map. Please contact Bernard Kay by email if you need further information.
Please also check the Departmental Events Calendar for other seminars which might be of interest. For example the Departmental Colloquium talks on Wednesdays sometimes are on mathematical physics.
15th January Thursday 4.20pm  Alexander Mikhailov (Leeds) Infinite dimensional automorphic Lie algebras 
19th January Monday 4.20pm  David McMullan (Plymouth) Charges in gauge theories 
22nd January Thursday 4.20pm  Bernard Kay (York) Quantum Field Theory in Curved Spacetime 1 
26th January Monday 4.20pm  Bernard Kay (York) Quantum Field Theory in Curved Spacetime 2 
29th January Thursday 4.20pm  Bernard Kay (York) Quantum Field Theory in Curved Spacetime 3 
2nd February Monday 4.20pm  Anne Taormina (Durham) Symmetries of string theory 
5th February Thursday 4.20pm  Atsushi Higuchi (York) Quantum Field Theory in Curved Spacetime 4 
9th February Monday 4.20pm  David Pearson (Hull) Spectral analysis of Schrodinger operators in Quantum Theory 
12th February Thursday 4.20pm  Atsushi Higuchi (York) Quantum Field Theory in Curved Spacetime 5 
16th February Monday 4.20pm  Tim Hollowood (Swansea) Integrability and gauge theories 
19th February Thursday 4.20pm  Atsushi Higuchi (York) Quantum Field Theory in Curved Spacetime 6 
26th February Thursday 4.20pm  Gary Gibbons (DAMTP, Cambridge) Consistent dimensional reductions from higher dimensional gravity and super gravity theories 
1st March Monday 4.20pm  Koenraad Audenaert (Bangor) There, and back again: Quantum theory and global optimisation 
4th March Thursday 4.20pm  Chris Fewster (York) Quantum Field Theory in Curved Spacetime 7 
8th March Monday 4.20pm  no seminar 
11th March Thursday 4.15pm G/010  Adrian Ottewill (University College, Dublin) Quantum fields near rotating black holes Note different venue and slightly earlier start 
15th March Monday 4.20pm  Chris Fewster (York) Quantum Field Theory in Curved Spacetime 8 
18th March Thursday 4.20pm  Chris Fewster (York) Quantum Field Theory in Curved Spacetime 9 
There, and Back Again: Quantum Theory and Global Optimisation
by Koenraad Audenaert (Bangor)
We consider a problem in quantum theory that can be formulated as an optimisation problem and present a global optimisation algorithm for solving it, the foundation of which relies in turn on a theorem from quantum theory. To wit, we consider the maximal output purity $\nu_q$ of a quantum channel as measured by Schatten $q$norms, for integer $q$. This quantity is of fundamental importance in the study of quantum channel capacities in quantum information theory. To calculate $\nu_q$ one has to solve a nonconvex optimisation problem that typically exhibits local optima. We show that this particular problem can be approximated to arbitrary precision by an eigenvalue problem over a larger matrix space, thereby circumventing the problem of local optima. The mathematical proof behind this algorithm relies on the Quantum de Finetti theorem, which is a theorem used in the study of the foundations of quantum theory.
We expect that the approach presented here can be generalised and will turn out to be applicable to a larger class of global optimisation problems. We also present some preliminary numerical results, showing that, at least for small problem sizes, the present approach is practically realisable.
Information on How to Reach the University is available. Goodricke College is building 24 on the campus map. Please contact Bernard Kay by email if you need further information.
Please also check the Departmental Events Calendar for other seminars which might be of interest. For example the Departmental Colloquium talks on Wednesdays sometimes are on mathematical physics.
22nd September Monday 2.15pm  Jason Szulc (York) Inequalities for marginal probabilities, quantum and classical 
13th October Monday 4.20pm  Mathematical Physics Group Meeting 
16th October Thursday 4.20pm  Akihiro Ishibashi (DAMTP, Cambridge) On stability of higher dimensional static black holes 
20th October Monday 4.20pm  Dan Tovey (Sheffield) Searching for Supersymmetric Dark Matter at Boulby Mine 
2325 October  ABCKLM Meeting 
23rd October Thursday 4.30pm  Erika Andersson (Strathclyde) Generalised measurements in quantum mechanics Note unusual time and place: The venue for this talk is now Derwent College room D/056 (10 minutes' walk from Mathematics Department) because the talk will take place within the ABCKLM Meeting (see link above) 
27th October Monday 4.20pm  Sean Hartnoll (DAMTP, Cambridge) Black hole instabilities, thermodynamics and duality 
30th October Thursday 4.20pm  Davide Fioravanti (York) An idea of universality in theories with a mass scale 
3rd November Monday 4.20pm  Werner Nahm (IAS, Dublin) Conformal Field Theory and an extended Bloch group 
10th November Monday 4.20pm  Tomihiro Harada (QMW, London) Selfsimilar solutions, critical behaviour and convergence to attractor in gravitational collapse 
13th November Thursday 4.20pm  Jiannis Pachos (Imperial College, London) Coherent evolutions in one and two dimensional optical lattices. 
17th November Monday 4.20pm  Niall MacKay (York) The Mathematics and Physics of Yangians 1 
20th November Thursday 4.20pm  Michael Melgaard (Uppsala) Spectral Theory of Schr"{o}dinger and Dirac Operators with External Magnetic Fields. Part II: AharonovBohm magnetic fields and LiebThirring inequalities. Note This is the second of two talks. The first (which is subtitled Part I: Eigenvalue Asymptotics ) will be at 11.15 am on Wednesday 19th November in G/109 in the GANT seminar series. But it will not be necessary to have gone to that talk to understand this one. 
24th November Monday 4.20pm  Niall MacKay (York) The Mathematics and Physics of Yangians 2 
27th November Thursday 4.20pm  Viv Kendon (Imperial College, London) Quantum versions of random walks for quantum computing 
1st December Monday 4.20pm  Charles Young (DAMTP, Cambridge) Local conserved charges in supersymmetric sigma models 
4th December Thursday 4.20pm  Niall MacKay (York) The Mathematics and Physics of Yangians 3 
8th December Monday 4.20pm  Niall MacKay (York) The Mathematics and Physics of Yangians 4 
11th December Thursday 4.20pm  Niall MacKay (York) The Mathematics and Physics of Yangians 5 
The objective of this network is to bring together groups in the UK having a common goal in pursuing the deep connections between mathematics and physics, primarily algebraic geometry, operator algebras and quantum groups in pure mathematics and conformal field theory, string theory and statistical mechanics in mathematical and theoretical physics. For more information and details of past meetings see the network's webpage.
The meeting is open to all. Please register with the local organiser to receive further information. There is no conference fee. Some funds are available to fund participants belonging to one of the network nodes.
We have booked Derwent Terrace Room from the morning of Thursday 23rd of October until the afternoon of Saturday 25th of October. This room will serve as our base room which we will use for tea, coffee and discussions while the talks will take place in nearby lecture rooms.
Thursday 23^{rd} October
morning  Gathering in Derwent Terrace Room 

1:00 pm  Lunch 
2:00 pm  Evgueni Sklyanin Separation of variables and related topics in room D/056 
3:15 pm  Zoltán Bajnok Boundary quantum field theories in room D/056 
4:30 pm  Erika Andersson: Generalised measurements in quantum mechanics in room D/056 
6:45 pm  Dinner in the Roger Kirk centre 
Friday 24^{th} October
8:30 am  Breakfast in Wentworth College 

9:30 am  Peter West tba in room L/037 
11:30 am  Alessio Corti and Vasily Golyshev in room D/056 
1:00 pm  Lunch 
2:15 pm  Alice Rogers: Morse Theory on Phase Space in room C/A/101 
3:30 pm  Reidun Twarok: Mathematical virology in room D/016 
4:30 pm  Tea and Coffe in Derwent Coffee room 
5:00 pm  Aidan Schofield: Noncommutative moduli of vector bundles in room D/016 
6:45 pm  Dinner in the "Go Down Restaurant" 
Saturday 25^{th} October
8:30 am  Breakfast in Wentworth College 

9:30 am  Jakob Stix: Introduction to logarithmic Geometry in room C/A/101 
11:00 am  Shahn Majid: Fock space representation for Anyons in room D/056 
12:15 pm  Lunch in Vanbrugh College 
There will be breaks with refreshments between all talks.
How to Reach the University of York.
The meeting will take place mostly in Derwent College. This is building 23 on the campus map
When you arrive at York railway station you can either take bus no 4 to Heslington Hall (building 1 adjacent to Derwent College) or take a taxi and ask the driver to drop you at Derwent College. Alternatively, in case you have a lot of luggage and will be staying in Wenworth College, see below, you could take the taxi to Wentworth College and then walk to Derwent College from there (5 or 10 minutes walk across campus).
For more information see "How to Reach the University of York".
The following participants will be staying in Wentworth College (arrival and departure dates in parentheses):
Generalised measurements in quantum mechanics
by Erika Andersson (Strathclyde)
In standard textbooks on quantum mechanics, a quantum measurement is usually described as a projection in the eigenbasis of the measured observable. This definition of projective (von Neumann) measurements is, however, too narrow. It does not allow us to describe all possible experimental measurement procedures. For example, we cannot accommodate joint measurements of noncommuting observables. Also, in a real experiment, with detector inefficiencies and other imperfections, what results is generally not a projective measurement on the original measured quantum system.
Generalised quantum measurements can describe any measurement that can be realised on a quantum system (provided that quantum mechanics holds). They are often called POM or POVM measurements, and are essentialy obtained by removing the requirement that the measurement operators have to be projectors. This talk will introduce generalised measurements and explain why they are useful. Generalised measurements have important applications for example in quantum communication theory, where one wants to know exactly what the optimal measurement strategy for a certain kind of signal is. They can also describe joint measurements of non commuting observables, as well as real experimental situations with imperfect detectors.
Selfsimilar solutions, critical behaviour and convergence to attractor in gravitational collapse
by Tomihiro Harada (QMW)
General relativity as well as Newtonian gravity admits selfsimilar solutions due to the scaleinvariance. This talk reviews selfsimilar solutions and their relevance to gravitational collapse. In particular, our attention is mainly paid on the crucial role of selfsimilar solutions in the critical behavior and attraction in gravitational collapse. Implications to cosmic censorship are also discussed.
Quantum versions of random walks for quantum computing
by Viv Kendon (Imperial)
Will we be using a quantum computer for numerical simulations in the next decade? Quantum computing offers the potential for exponentially more efficient calculations than classical computers. But not for all problems, we know of a set that make use of a quantum version of Fourier Transforms for their speed up (including factoring large numbers) and one example using a quantum version of a random walk. Other classes of problems, such as searching an unsorted database, can have at most a quadratic speed up. And then there are all the difficulties of actually building a quantum computer... I will give an introductory overview of quantum computing, suitable for the nonspecialist, in the course of which my own work on quantum versions of random walks will get a brief mention.
Conformal Field Theory and an extended Bloch group
by Werner Nahm (IAS, Dublin)
Integrable perturbations of conformal quantum field theories in two dimensions and invariants of hyperbolic manifolds are both described by an extension of the Bloch group, an object in algebraic Ktheory. For the quantum field theories, the Bethe ansatz yields finite order elements in this group, which statisfy certain algebraic equations. Examples are provided by pairs of ADET diagrams, and in the case of two Atype diagrams all solutions of these equations are obtained.
Coherent evolutions in one and two dimensional optical lattices
by Jiannis Pachos (Imperial)
We consider the controlled manipulation of one dimensional bosonic or fermionic optical lattices, induced by tunnelling or collisions of the atoms within the lattice. As an application, we discuss the implementation of quantum computation where each atom provides one qubit. The resulting quantum register is robust against dephasing due to longitudinal lattice decoherence. Further studies concern one or two dimensional optical lattices and result in solid state models with new intriguing three body interactions.
Information on How to Reach the University is available. Goodricke College is building 24 on the campus map. Please contact Clare Dunning by email if you need further information.
Please also check the Departmental Events Calendar for other seminars which might be of interest. For example the Departmental Colloquium talks on W ednesdays sometimes are on mathematical physics.
28 April Monday 4.20pm  José Miguel Figueroa y O'Farrill (Edinburgh) Plane wave limits in string and gauge theory 
6 May Tuesday 11:30 am Unusual Time  Mark Gould (Brisbane) Classification of unitary representations of simple Lie superalgebras 
22nd May Thursday 4.20pm  Evgueni Sklyanin (York) Qoperator and separation of variables for Jack polynomials 
29th May Thursday 4.20pm  Betti Hartmann (Durham) Monopoles and "hairy" black holes 
2nd June Monday 4.20pm  Valeria Del Prete (KCL) A theoretical model for population coding of mixed continuous and discrete stimuli: from the linear rise to the asymptotic regime. 
5th June Thursday 4.20pm  Chris Fewster (York) Stability of quantum systems at three scales 
9th June Monday 4.20pm  Cristina Zambon (York) Classically integrable field theories with boundary conditions 
16th June Monday 4.20pm  Andy Hone (UKC) Peakons, Poisson brackets and a functional equation. 
19th June Thursday 4.20pm  Hugh Jones (Imperial) PT symmetry versus Hermiticity in Quantum Mechanics and Quantum Field Theory 
23rd June Monday 4.20pm  Jorma Louko (Nottingham) Higher dimensional Einstein black holes and AdS/CFT conjecture 
26th June Thursday 4.20pm  Roger Behrend (Cardiff) Reflections on the Reflection Equation 
7 July Monday 4.20pm  Martin Halpern (Berkeley) Twisted Open Strings from Closed Strings: The WZW Orientation Orbifolds 
22nd July Tuesday 4.15pm  Christopher Fuchs (Bell Labs) What is the Difference between a Quantum Observer and a Weatherman? 
25th July Friday 2.15pm  Ruediger Schack (Royal Holloway) Compatible quantum state assignments 
8th September Monday 2.15pm  Rainer Verch (Max Planck Institute, Leipzig) Generally covariant quantum field theory and spin and statistics for quantum fields on manifolds 
22nd September Monday 2.15pm  Jason Szulc (York) Inequalities for marginal probabilities, quantum and classical 
Information on How to Reach the University is available. Goodricke College is building 24 on the campus map. Please contact Gustav Delius by email if you need further information.
Please also check the Departmental Events Calendar for other seminars which might be of interest. For example the Departmental Colloquium talks on Wednesdays sometimes are on mathematical physics.
16 January Thursday 4.20pm  Sam Braunstein (Bangor) Entanglement in quantum information processing 
20 January Monday 4.20pm  Ed Corrigan (York) Graduate Lectures on String Theory 
30 January Thursday 4.20pm  Ian Drummond (Cambridge) Bimetric gravity  an alternative to dark matter 
6 February Thursday 4.20pm  Jonathan Halliwell (Imperial) Decoherence: Some Recent Developments 
27 February Thursday 4.20pm  Fay Dowker (QMW) A spontaneous collapse model on a lattice 
6 March Thursday 4.20pm  Francesco Ravanini (Bologna) Excited Boundary Flows in the Tricritical Ising Model 
13 March Thursday 4.20pm  Jon Links (Brisbane) Exactly solvable model for atomicmolecular BoseEinstein condensates 
17 March Monday 4.20pm  Klaus Fredenhagen (Hamburg) Time as an observable in quantum mechanics 
19 March Wednesday 4.20pm  Klaus Fredenhagen (Hamburg) Quantum field theory in curved spacetime 
20 March Thursday 4.20pm  Klaus Fredenhagen (Hamburg) Quantum field theory on noncommutative spacetimes 
Mathematical Physics Seminars 
22 August Thursday 4.20pm  Masashi Hamanaka (Univ. of Tokyo, YITP) Noncommutative ADHM construction 
14 October Monday 4.20pm  Tony Sudbery (York) Nocollapse interpretations of quantum mechanics 
17 October Thursday 4.20pm  Bernard Kay (York) Remarks on the Foundations of Quantum Mechanics 
21 October Monday 4.20pm  Postponed due to illness Deborah Konkowski (US Naval Academy) Are classically singular spacetimes quantummechanically singular as well? 
24 October Thursday 4.20pm  Leah Henderson (Bristol) Optimal entanglement generation from quantum operations 
28 October Monday 4.20pm  Ed Corrigan (York) Graduate Lectures on String Theory 
31 October Thursday 4.20pm  Atsushi Higuchi (York) Radiation reaction in scalar QED 
4 November Monday 4.20pm  Ed Corrigan (York) Graduate Lectures on String Theory 
7 November Thursday 4.20pm  Deborah Konkowski (US Naval Academy) Are classically singular spacetimes quantummechanically singular as well? 
11 November Monday 4.20pm  Ed Corrigan (York) Graduate Lectures on String Theory 
14 November Thursday 4.20pm  Marco Bellacosa (Bologna) Nonlinear Integral Equations for Quantum Integrable Models with Boundaries 
18 November Monday 4.20pm  Ed Corrigan (York) Graduate Lectures on String Theory 
21 November Thursday 4.20pm  Wojtek Zakrzewski (Durham) Some Aspects of the Modified Nonlinear Schrodinger Equation 
25 November Monday 4.20pm  Ed Corrigan (York) Graduate Lectures on String Theory 
28 November Thursday 4.20pm  Mitch Pfenning (York) Quantum Inequalities 
2 December Monday 4.20pm  Ed Corrigan (York) Graduate Lectures on String Theory 
5 December Thursday 4.20pm  Joe Hilling (York) The History Projector Operator Formalism of Consistent Histories 
9 December Monday 4.20pm  Ed Corrigan (York) Graduate Lectures on String Theory 
12 December Thursday 4.20pm  Emily King (York) Applications of consistent histories 
22 April Monday 4.20pm  Richard Woodard (University of Florida) A NonTechnical (Honest!) Description of the Problem of Quantum Gravity 
2 May Thursday 4.20pm  Patrick Dorey (Durham) Exact Smatrices for the qstate Potts models 
6 May Monday 4.20pm  Gustav W Delius (York) Graduate Lectures on Solitons and Boundaries: Classical Soliton Solutions 
9 May Thursday 4.20pm  Theodora Ioannidou (Kent) Bogomolny YangMillsHiggs Solutions in (2+1) antide Sitter Space 
13 May Monday 4.20pm  Paul Sutcliffe (Kent) Solitons in the Heart 
16 May Thursday 4.20pm  Charis Anastopoulos (Utrecht) Quantum mechanical histories and interference phases 
20 May Monday 4.20pm  Bernhard Baumgartner (Vienna) Order relations for sets and inequalities for entropies 
21 May Tuesday 5.20pm Note special time and venue: V/123  LMS Hardy Lecture Alexander Its The nonlinear Schroedinger equation on the halfline and on the interval 
27 May Monday 4.20pm  Stephen Siklos (DAMTP) Singularities and invariants in general relativity 
30 May Thursday 4.20pm  Hendryk Pfeiffer (DAMTP) Spin foam models in quantum gravity 
6 June Thursday 4.20pm  S.M. Chitre (Tata Institute) The seismic sun and solar neutrinos 
13 June Thursday  Meeting of the North British Mathematial Physics Seminar 
17 June Monday 4.20pm  Thomas Roman (Connecticut) Constraints on Spatial Distributions of Negative Energy 
20 June Thursday 4.20pm  Tony Sudbery (York) Quantum Fallacies A guided discussion 
14 January Monday 4.20pm  Jose FigueroaOFarrill (Edinburgh) Lie Branes: recent results 
17 January Thursday 4.20pm  Larry Ford (Tufts) Focusing Vacuum Fluctuations 
21 January Monday 4.20pm  Katsushi Ito (Tokyo Institute of Technology) Scattering of noncommutative solitons 
24 January Thursday 4.20pm  Kevin Graham (King's College, London) Perturbations of Conformal Field Theory by Boundary Condition Changing Operators 
31 January Thursday 4.20pm  Atsushi Higuchi (York) Discussion on Topological KTheory 
4 Feburary Monday 4.20pm  Atsushi Higuchi (York) Discussion on Topological KTheory 
5 February Tuesday 4.20pm (Note unusual day)  Michael Atiyah (Edinburgh) Ktheory and charges 
7 Feburary Thursday 4.20pm  Yann Golanski (NNDG York) Modelling of early stages of stellar formation 
11 February Monday 4.20pm  James Gray (Newcastle) Moving branes in Heterotic Mtheory cosmology 
14 February Thursday 4.20pm  Ian Lawrie (Leeds) Dissipation and friction in the equations of motion for scalar fields 
18 February Monday 4.20pm  David Toms (Newcastle) Quantum Fields off the Brane 
21 February Thursday 4.20pm  Andrei Bytsko (Steklov Institute, St.Petersburg) Hamiltonians for higher spin XXZ chains 
11 March Monday 4.20pm  Robert Oeckl (Marseille) tba 
15 October Monday 4.20pm  Jason Szulc (York) The Nobelprizewinning experiment on BoseEinstein condensation 
18 October Thursday 4.20pm  Atsushi Higuchi (York) Lowfrequency scalar absorption cross sections for stationary black holes 
22 October Monday 4.20pm  Alan George (York) Quintessence 
25 October Thursday 4.20pm  Ruth Gregory (Durham) Braneworld instantons 
29 October Monday 4.20pm  Mitch Pfenning (York) Radiation reaction in electromagnetism and general relativity: I electromagnetism 
1 November Thursday 4.20pm  Mitch Pfenning (York) Radiation reaction in electromagnetism and general relativity: II gravitation 
5 November Monday 4.20pm  Chris Fewster (York) Microlocal Analysis This seminar forms part of the York Mathematics Department Series of expository seminars for staff and students 
8 November Thursday 4.20pm  Ian Jack (Liverpool) Finite noncommutative theories 
12 November Monday 4.20pm  Tony Sudbery and Jason Szulc (York) Report on the Turin Meeting on Quantum Information (Note that the planned talks by Jochen Weller, previously announced in this slot, have had to be cancelled.) 
15 November Thursday 4.20pm  (no seminar) 
19 November Monday 4.20pm  Ian McIntosh (York) A rough and ready guide to cohomology. Part 2: Cech cohomology This seminar forms part of the York Mathematics Department Series of expository seminars for staff and students 
22 November Thursday 4.20pm  Gustav Delius (York) Quantum group symmetry in the boundary sineGordon model and soliton reflection amplitudes 
26 November Monday 4.20pm  John Loftin (Columbia) Toward a compactification of the moduli space of convex RP(2) surfaces 
3 December Monday 4.20pm  Atsushi Higuchi (York) The renormalization group This seminar forms part of the York Mathematics Department Series of expository seminars for staff and students 
10 December Monday 4.20pm  Chongsun Chu (Durham) Aspects of noncommutative gauge theories 
13 December Thursday 4.20pm  Rafael Nepomechie (Miami) Supersymmetric integrable boundary QFT in 1+1 dimensions 



Mondays & Thursdays:  Talks start at 4:20 pm. They are preceeded by coffee and biscuits. The seminars are open ended but there will be a short break after about 50 minutes. They take place in the very relaxed atmosphere of Room V/131 in Vanbrugh College. 
Wednesdays:  These are the Departmental Seminars and are supposed to be accessible to a general mathematics audience. They take place in room V/131, Vanbrugh College, at 4.00 pm. Tea will be available at 3.30 p.m. in the Senior Common Room, Vanbrugh College. 
Information on How to Reach the University is available. Vanbrugh College is building 25 on the campus map. Please contact Gustav Delius by email if you need a parking permit or would like further information.
Please note that this is the tentative evolving program. It is advisable to recheck the page shortly before each talk. For further details or to be placed on the mailing list please contact Dr. B.S. Kay or Dr. G.W. Delius.
30 April Monday 4.20pm  Dr Konstantina Savvidou (Imperial) Time in histories theory 
3 May Thursday 4.20pm  Dr Pascal Baseilhac (York) Expectation values of descendent fields in integrable quantum field theories 
10 May Thursday 4.20pm  Dr Anastasia Doikou (York) Principal chiral model scattering and the alternating quantum spin chain 
16 May Wednesday 4.00pm  Professor Paul Glendinning (UMIST) On the unique expansion of numbers in noninteger bases: a dynamical systems approach 
17 May Thursday 4.20pm  Dr Rod Crewther (Adelaide) Why I want YangMills topological charge to take noninteger values 
23 May Wednesday 4.00pm  Dr Alan Beardon (Cambridge) Continued Fractions: Old and New 
24 May Thursday 4.20pm  Professor Rex Godby (York) Manybody perturbation theory for electrons in real materials 
30 May Wednesday 4.00pm  Dr Martin Matthieu (Queen's, Belfast) Elementary Operators on Calkin Algebras 
31 May Thursday 4.20pm  Dr Chris Fewster (York) Quantum Inequalities for the Dirac Field 
6 June special time Wednesday 4.20pm  Ryu Sasaki (YITP, Kyoto University) Hierarchies of Spin Models related to CalogeroMoser Models (hepth/0105197) 
7 June Thursday 4.20pm  Daniel Vanzella (Sao Paulo) Decay of accelerated protons and the FullingDaviesUnruh effect 
13 June Wednesday 4.00pm  Dr Julian Barbour The dynamics of pure shape 
14 June Thursday 4.20pm  Dr Julian Barbour Relativity without Relativity 
15 June special time Friday 11.30am  Dr Laszlo Feher (Szeged, Hungary) Interpretations and constructions of dynamical rmatrices 
28 June Thursday 4.20pm  Professor Peter Holdsworth (ENS Lyon) Spin liquides glasses and ice: degeneracy and degeneracy lifting in frustrated magnetism 
9 July special time Monday 4.20pm  Prof Larry Ford (Tufts) Where is the Negative Energy?  Constraints on Spatial Distributions of Negative Energy in Quantum Field Theory 
The topics include: Bäcklund transformations, Qoperator, separation of variables, integrable boundary conditions. The variety of techniques is illustrated on a few examples: Toda lattice, XXX magnetic chain, CalogeroMoser model.
LiouvilleArnold's definition of integrability. Isospectral transform method: Lax matrix. LiePoisson groups: rmatrix. Symplectic leaves of rmatrix Poisson bracket. XXX magnetic chain as the generic integrable model associated to the sl_{2}invariant rmatrix. Degenerations of XXX model: DST model, Toda lattice, Gaudin model.Quantization. Correspondence rules. Quantum canonical transformations: Fock formula. Quantum groups, Yangians. XXX magnetic chain, algebraic Bethe Ansatz.
Axioms of BT: algebraicity, locality, canonicity, commutativity (Veselov theorem), spectrality. General construction of BT for the models associated to the sl_{2}invariant rmatrix. Examples: Toda lattice, XXX chain, CalogeroMoser (Ruijsenaars) model.
History: motivations, Baxter's construction, PasquierGaudin, BazhanovLukianovZamolodchikov works. Relation of Q and BT.Qoperator for the XXX model  a detailed study. Universal sl_{2}invariant Rmatrix. Qoperator as trace of a monodromy matrix. 3 kinds of Qoperators. Factorization of the Rmatrix and the Qoperator. Fusion and wronskian identities. Kernels and symbols of Q.
Definitions (classical and quantum case).Classical SoV. General construction: poles of the eigenvectors of the Lax matrix. Normalization problem. Examples: Toda lattice, XXX model, CalogeroMoser model.
Relation of SoV and BT (Q). SoV from BT (KuznetsovSklyanin). BT from SoV (KuznetsovVanhaecke).
Quantum SoV. Examples: Toda lattice, XXX model, Macdonald polynomials.
General construction based on exchange algebras. Comodules over quantum groups. Examples: XXX model, Toda lattice, Nonlinear Schröodinger equation.Bethe Ansatz, SoV, Qoperator for the systems with boundary.



Mondays & Thursdays:  Talks start at 4:20 pm. They are preceeded by coffee and biscuits. The seminars are open ended but there will be a short break after about 50 minutes. They take place in the very relaxed atmosphere of Room V/131 in Vanbrugh College (building 25 on campus map). 
Wednesdays:  These are the Departmental Seminars and are supposed to be accessible to a general mathematics audience. They take place in room V/131, Vanbrugh College, at 4.00 pm. Tea will be available at 3.30 p.m. in the Senior Common Room, Vanbrugh College. 
11 January Thursday 4.20pm  Dr Roberto Tateo (Durham) Perturbed boundary conformal field theory and quantum mechanics 
15 January Monday 4.20pm  Spyros Kouris (York) Graviton twopoint function in de Sitter spacetime 
18 January Thursday 4.20pm  Clare Dunning (York) Ordinary differential equations and integrable quantum field theories 
22 January Monday 4.20pm  Dr Keith Anguige Isotropic Cosmological Singularities 
24 January Wednesday 4 pm  Dr Steven Bramwell (University College London) Universal Fluctuations in Correlated Systems 
25 January Thursday 4.20pm  Professor Dmitri Vassiliev (Bath) Spectral asymptotics for partial differential operators and microlocal analysis 
29 January Monday 4.20pm  Jason Szulc (York) Shor's factorisation algorithm 
31 January Wednesday 4 pm  Dr Benjamin Steinberg (Porto) What is partial symmetry? 
1 February Thursday 4.20pm  Dr Davide Fioravanti (Durham) DE RERUM NATURA id est THE IMPORTANCE OF BEING SYMMETRY 
7 February Wednesday 4 pm  Dr Paolo Papi (Rome) An overview on adnilpotent ideals of Borel subalgebras 
8 February Thurday 4.20pm  Dr Andrew Mathas (Sydney) Affine Hecke algebras, ArikiKoike algebras and Fock spaces 
12 February Monday 4.20pm  Dr Clifford Johnson (Durham) Gauge Theory Dynamics from DBrane Probes 
13 February Tuesday 10.15pm  Dr Evgueni Sklyanin (St. Petersburg) Note that this is not a regular seminar talk but a presentation in connection with the readership position in our group. 
14 February Wednesday 4 pm  Professor J Greenlees (Sheffield) Implausible equivalences and duality 
15 February Thurday 4.20pm  Dr Niall MacKay (York) Vibrations of symmetric molecules and the Buckyball 
19 February Monday 4.20pm  Professor Vladimir Rittenberg (Bonn) The twocomponent Burgers equation and applications to stochastic processes 
21 February Wednesday 4 pm  Professor A Veselov (Loughborough) Configurations of hyperplanes in integrable systems 
26 February Monday 4.20pm  Dr Vadim Kuznetsov (Leeds) Bäcklund transformations go digital 
28 February Wednesday 4 pm  Professor P Glendinning (UMIST) Postponed because of bad weather On the unique expansion of numbers in noninteger bases: a dynamical systems approach 
7 March Wednesday 4 pm  Dr M Dritschel (NewcastleonTyne) to be announced 
7 March Thursday 4 pm  Professor Tony Sudbery (York) Groups, geometries and mechanics 
12 March Monday 4.20pm  Dr Konstantina Savvidou cancelled due to illness 
22 March Thursday 4.20pm  Professor Tohru Eguchi (Tokyo) String propagation on singular CalabiYau manifolds 
Mathematical Physics Seminars 
Days:  Mondays and Thursdays 

Time:  talk at 4:15 pm, preceeded by coffee and biscuits The seminars are open ended but there will be a short break after about 50 minutes. 
Location:  Mondays in room G/010 in Goodricke College (building 22 on campus map), Thursdays in V/131 in Vanbrugh College (building 25 on campus map) 
Other mathematical physics seminars take place in the Wednesday Departmental Seminar series and for convenience these too are listed in the programme below.
Wednesday, 3 May:  Departmental Seminar at 4:00 in V/131 JY Thibou (Paris) Introduction to the Combinatorics of Ribbon Tableaux 
Thursday, 4 May:  Niall MacKay (York) The Principal Chiral Model on the HalfLine 
Monday, 8 May:  John Cardy (Oxford) Conformal Field Theory and Percolation 
Wednesday, 10 May:  Departmental Seminar at 4.00 in V/131 T Sapatinas (Kent) An introduction to wavelet decomposition and shrinkage 
Monday, 15 May:  Francois Englert (Brussels) The FeffermanGraham ambiguity and the holographic principle 
Wednesday, 17 May:  Departmental Seminar at 4:30 in V/131 Peter Phillips (Yale) Trends and Spurious Regression 
Monday, 22 May:  Sergei Lukyanov (Rutgers) Finite temperature expectation values of local fields in the sinhGordon model 
Wednesday, 24 May:  Departmental Seminar at 4:00 in V/131 Fran Burstall (Bath) Integrable systems in Conformable Geometry 
Thursday, 25 May:  Reidun Twarock (York) An aperiodic analog to the Virasoro algebra via quasicrystal techniques 
Wednesday, 31 May:  Departmental Seminar at 4:00 in V/131 Stephen Bramwall (University College London) Universal Fluctuations in Correlated Systems 
Wednesday, 7 June:  Departmental Seminar at 4:00 in V/131 Michael Berry (Bristol) The architecture of diffraction catastrophes 
Monday, 12 June:  Peter Goddard (Cambridge) An approach to Conformal Field Theory 
Wednesday, 14 June:  Departmental Seminar at 4:00 in V/131 Paul Turner (HeriotWatt) Homotopy Quantum Field Theories 
Thursday, 22 June:  Don Marolf (Syracuse) String/MBranes for relativists 
Thursday, 29 June:  Tony Sudbery (York) Why Am I Me? and other interesting questions 
Monday, 3 July:  Ryu Sasaki (Yukawa Institute, Kyoto) The Quantum CalogeroMoser Model 
Monday, 10 July:  AM Semikhatov (Lebedev and Durham) Integrable Representations as Collective (``Quasiparticle'') Excitations 
Monday seminars take place at 4.15 in room G/010
17 January:  Chris Fewster Quantum Inequalities from Microlocal Analysis 
24 January:  Liu Zhao 2Parameter Deformations of Affine Lie Algebras 
31 January:  Pascal Baseilhac From Reflection Amplitudes to Vacuum Expectation Values in Integrable Quantum Field Theories I 
7 February:  Spyros Kouris Large Distance Behaviour of the Linearized Gravity TwoPoint Function in De Sitter Spacetime 
14 February:  Ian McIntosh Toda Systems and their Poisson Structures: the Coadjoint Orbit Method I 
21 February:  Ian McIntosh Toda Systems and their Poisson Structures: the Coadjoint Orbit Method II 
28 February:  Ian McIntosh Toda Systems and their Poisson Structures: the Coadjoint Orbit Method III 
6 March:  Katrin Wendland (Bonn) (Crystallographic) Orbifold Conformal Field Theories 
13 March:  Everyone Informal Discussion on Quantum Gravity 
20 March:  Hilary Carteret (York) {Local Symmetry properties of threeparticle pure states> + Local Symmetry properties of multiparticle pure states>}/sqrt(2) 
Thursday seminars take place at 4.15 in room V/131 (preceded by coffee at 4.00 in V/135).



Mondays & Thursdays:  Talks start at 4:20 pm. They are preceeded by coffee and biscuits. The seminars are open ended but there will be a short break after about 50 minutes. They take place in the very relaxed atmosphere of Room V/131 in Vanbrugh College (building 25 on campus map). 
Wednesdays:  These are the Departmental Seminars and are supposed to be accessible to a general mathematics audience. They take place in room V/131, Vanbrugh College, at 4.00 pm. Tea will be available at 3.30 p.m. in the Senior Common Room, Vanbrugh College. 
12 October Thursday 4.20pm  Phil Isaac (Brisbane) Quantum Lie Algebras This will be a generally accessible talk about quantum groups and quantum Lie algebras 
16 October Monday 4.20pm  Prof. John Roberts (Rome) Theory of Superselection Sectors 
30 October Monday 4.20pm  Brett Gibson (York) Boundary Breathers in the sineGordon model on the half line 
2 November Thursday 4.20pm  Dr Dirk Kreimer (Mainz) From the combinatorics of Feynman diagrams to running physical parameters 
8 November Wednesday 4pm  Cancelled because of flooding: Dr M Dritschel (NewcastleuponTyne) 
9 November Thursday 5:15pm room: V/045  Dr Chris Fewster (York) Open Lecture: A crash course in quantum mechanics This is part of a lecture series for nonscientists starting immediately after our usual seminar slot. 
15 November Wednesday 4pm  Dr Stephen Bramwall (University College London) Postponed because of flooding 
16 November Thursday 4:20pm  Dr Ruediger Schack (Royal Holloway) Postponed because of flooding 
20 November Monday 4:20pm  Dr Lucien Hardy (C.Q.C. Oxford) Can quantum theory be obtained from reasonable axioms? 
22 November Wednesday 4pm  Professor P C Chatwin (Sheffield) Aspects of the only unsolved problem of classical physics 
23 November Thursday 5:15pm room: V/045  Dr Chris Fewster (York) Open Lecture: Neither here nor there but both: the central mystery of quantum mechanics This is part of a lecture series for nonscientists starting immediately after our usual seminar slot. 
29 November Wednesday  Yorkshire Differential Geometry Day 
30 November Thursday 5:15pm V/045  Professor Tony Sudbery (York) Open Lecture: Putting weirdness to work: quantum information and quantum computing This is part of a lecture series for nonscientists starting immediately after our usual seminar slot. 
4 December Monday 4:20pm  Dr Michael Roesgen (Bonn) Applications of (essential) paths in conformal field theory 
6 December Wednesday 4pm  Dr James Vickers (Southampton) How to multiply distributions 
7 December Thursday 4:20pm  Dr Ruediger Schack (Royal Holloway) Generalized measurements and quantum Bayes rule 
11 December Monday 4:20pm  Dr David Rideout (Syracuse) A Stochastic Growth Dynamics for Causal Sets 
25 October:  5minute minitalks by F. Cornish, T. Brzezinski, E. Corrigan, G. Delius, C. Fewster, A. Higuchi, B. Kay, I. McIntosh, M. Nazarov, A. Sudbery. 
1 November:  Gustav Delius Conformal Field Theory I 
8 November:  Tomasz Brzezinski Algebraic Bethe Ansatz I 
15 November:  Gustav Delius Conformal Field Theory II 
22 November:  Tomasz Brzezinski Algebraic Bethe Ansatz II 
29 November:  Gustav Delius Conformal Field Theory III 
6 December:  Ed Corrigan The ADHM Construction I 
13 December:  Ed Corrigan The ADHM Construction II 
21 October:  Elizabeth Winstanley (Oxford) Black holes, infinite hair and antide Sitter space 
3 November:  free discussions 
11 November:  Maxim Nazarov (York) Reflection equation and classical Lie algebras 
18 November:  Christopher Fewster (York) A general quantum inequality 
25 November:  Tomasz Brzezinski (York) Algebraic Bethe Ansatz III: Solving the Bethe equations 
2 December:  Vadim Kuznetsov (Leeds) Bäcklund transformations for classical and quantum integrable systems 
9 December:  Nicholas Dorey (Swansea) title tba 
I gave three introductory lectures on conformal field theory:
Obviously I only scratched the surface. I recommend the following for further reading:
The links point to a local copy of the scanned versions of the papers stored at KEK.
A full list of publications by all members of the Department is also available.
If you are fascinated by the mathematical beauty of physical theories, we invite you to apply to join our group as a graduate student and share our excitement.
If you would like to know how to apply for admission as a graduate student you should check out the main Mathematics PhD page where you can find a link to the online application form. There are various possibilities of funding including EPSRC, PPARC and University scholarships.
Once you are one of our graduate students you will benefit from the congenial atmosphere which characterizes our group.
You will choose one of our members of staff as your supervisor who guides your research work. In addition there will be two more members of staff who keep themselves informed about your research and who together make up your thesis advisory panel. You can find out more about the formal side of being a graduate student here on the departmental postgraduate study pages.
For you, more important than these formal arrangements will be the personal interactions within our group. You will have plenty of opportunity for informal conversations during our morning or afternoon coffee breaks. These take place at 11:00 and 16:00 in G/109, a room with comfortable chairs but also with a blackboard if you feel the urge to discuss research.
Twice a week, on Tuesday lunchtimes (14:00) and Thursday afternoons (16:15), we hold our very relaxed seminars in the cofffee room. We often have outside speakers on Thursdays but there remain plenty of free slots for local speakers and everyone can make suggestions for topics. The seminars are in the "Russian style", which means that the audience can interrupt the speaker with questions and often even longer discussions. It can happen that people from the audience come to the blackboard themselves to discuss a point. And the seminars are open ended; people simply leave when they have heard enough.
We do not run a formal MSc course, but we participate in the MAGIC network of videoconferenced graduate lectures. We also run local short series of lectures on topics of interest. For example, we have had short courses on conformal field theory, the algebraic Bethe Ansatz, string theory and Dbranes, the ADHM construction, the coadjoint orbit method, Yangians, and quantum fields in curved spacetime.
Please take a look at the description of our research areas. One characteristic you will notice is that we stress that much of the beauty of physical theories lies in their mathematical details. We are not content with just the broad brushstrokes.
Ed Corrigan has been investigating the properties of defects and boundaries in integrable (but not conformal) field theories with a view to classifying all possibilities. This is an extensive project with many facets. Some of the ideas and techniques are algebraic in flavour, others analytical, but most are novel and there are a number of areas suitable for development by a PhD student.
Niall MacKay works principally on algebraic aspects of quantum integrability, and is happy to supervise students on the hidden symmetry algebras (typically Yangians and other 'quantum groups') of integrable models, their representations and particle content. Most projects are suitable for students with an MSclevel background in theoretical physics (including strings, supersymmetry, QFT etc.), but some are more algebraic and may be suitable for pure mathematicians with an interest in mathematical physics. Past and current students have worked on: boundary scattering in AdS/CFT; the YangBaxter equation and invariant tensors of exceptional Lie groups; twistdeformed manifolds and cosmology; conserved charges in supergroup sigma models; boundary scattering in principal chiral models; quantum affine Toda solitons.
Niall has also recently developed an interest in the mathematical modelling of warfare, and has published papers on Lanchester theory, especially in its historical context. Possible research projects would be in this area and in the mathematical modelling of counterinsurgent warfare.
Henning Bostelmann is interested in the mathematical foundations of physics; specifically, of relativistic quantum physics (quantum field theory). While quantum field theory is a well established topic since more than 50 years, its mathematically rigorous description, in particular of its nonperturbative aspects, is still largely incomplete. He analyses these questions using advanced methods of functional analysis (operator algebras).
Topics that he is working on, and has worked on, include: the shortdistance scaling limit of quantum field theories; the relation between pointlike observables (quantum fields) and bounded observables in open regions; the covariant formulation of these for quantum theories on curved spacetime, i.e., in a gravitational background.
Chris Fewster works on the mathematically rigorous formulation of quantum field theory in curved spacetimes (QFT in CST). In this theory, the propagation of the quantum fields is affected by the curvature of spacetime, but (usually) one neglects the "backreaction" effect of the quantum fields on the spacetime. He has supervised seven PhD students in this area, with two main foci:
Quantum energy inequalities Unlike most classical forms of matter, quantum fields can have local energy densities that are negative. However, quantum field theory contains mechanisms (deeply connected to the uncertainty principle) that result in the energy density not being too negative on average. These mechanisms are expressed by results called Quantum Energy Inequalities (QEIs). Chris Fewster has supervised a number of PhD students on these questions. Simon Dawson (PhD 2006) investigated numerical QEIs and also produced the first closedform expression for QEIs for the Dirac field in CST. Calvin Smith (PhD 2006) obtained the first "absolute" QEIs in CST, while Lutz Osterbrink (PhD 2007) found the first QEIs applicable to the nonminimally coupled scalar field. An introduction to QEIs and some of the related techniques can be found in Chris Fewster's lecture notes.
Locally covariant QFT Quantum field theory in Minkowski space depends in many ways on the high degree of spacetime symmetry. General curved spacetimes lack any symmetry at all, which makes it hard to prove general statements about general quantum field theories (as opposed to specific models). A major development was the introduction by Brunetti, Fredenhagen and Verch of a locally covariant formulation of QFT in CST based on techniques of category theory. Chris Fewster's former students Ko Sanders (PhD 2008), Matthew Ferguson (PhD 2013) and Benjamin Lang (PhD 2015) have worked on various aspects of locally covariant QFT, including the proof of a ReehSchlieder theorem and the formulation of the Dirac field (Sanders), the dynamical locality of the extension of scalar field theory to incorporate Wick polynomials (Ferguson), and an investigation of dynamical locality and related issues for electromagnetism (Lang).
Hadamard states Quantum field theory admits a very large space of states, most of which are unphysical. The class of Hadamard states is a wellstudied set of physical states, which play an important role in QFT in CST. With Benjamin Lang, Chris Fewster has recently given a new construction of a class of Hadamard states for the Dirac field in certain spacetimes. A number of open questions remain in this area and are being pursued by current students Francis Wingham and Michael Kiss (both cosupervised with Kasia Rejzner).
In addition, Chris Fewster is interested in other aspects of QFT in flat and curved spacetime. Recently, with David Hunt (PhD 2012) he studied the quantization of linearized gravity on background spacetimes solving the Einstein equations with cosmological constant, thus making contact with Atsushi Higuchi's work (see elsewhere on this page).
Kasia Rejzner is interested in mathematical structures relevant for quantum field theory (QFT) and quantum gravity. In particular, she works on problems involving QFT on curved spacetimes, using the locally covariant setting proposed by Brunetti, Fredenhagen and Verch (CMP 2003). This setting can also be extended to include effective quantum gravity models. Kasia is also interested in abstract algebraic and analytical structures appearing in renormalization. Possible project topics could focus on:
Mathematical structures in renormalization Renormalization is a powerful set of tools used in Quantum Field Theory to construct interacting models (perturbatively). Usually, it is associated with the idea of "removing the divergences," but there are also more rigorous formulations of the renormalization problem that allow to see renormalization as a mathematically welldefined procedure. One of such approaches is the EpsteinGlaser renormalization scheme, which recently has been successfully applied in QFT on curved spacetimes. Potential PhD projects would aim at investigating abstract mathematical structures appearing in this renormalization scheme, or at applying this scheme in interesting physical examples.
Quantum gravity and cosmology Quantizing gravity is one of the greatest challenges of modern theoretical physics. At the moment, the full theory is not known and there are several competing approaches to finding it. In a recent paper of R. Brunetti, K. Fredenhagen and K. Rejzner (2013) it was shown that a perturbative model of effective quantum gravity can be constructed using the framework of locally covariant QFT (formerly used only for QFT on curved spacetimes). This opens a way for applications in cosmology and black hole physics. Potential PhD projects would involve constructing models that allow to compute quantum gravity corrections to known physical processes.
Eli Hawkins has interests ranging from mathematical physics to pure mathematics, and would be happy to supervise PhD projects on any of these topics. The main theme of his research is the relationship between classical (geometric) structures and quantum (noncommutative algebraic) structures. His recent interests include algebraic quantum field theory, operads, and Kontsevich formality. His previous student, James Waldron (PhD 2015) studied Lie algebroids over differentiable stacks. Some specific possible project topics are:
KaluzaKlein without extra dimensions A KaluzaKlein model is a type of unified field theory that seeks to unify gravitation with electromagnetism and YangMills interactions by supposing that spacetime is more than 4dimensional. In the mathematical framework of Lie algebroids, it is possible to formulate a similar type of model without resorting to extra dimensions. The project would be to investigate this class of models.
Obstructions to quantization When does there exist a continuously parametrized strict deformation quantization of a Poisson manifold? The project would be to extend results for the 2dimensional sphere to arbitrary Poisson manifolds. This will require studying the stability of Poisson maps and Lie algebroid homomorphisms.
Geometric quantization of symplectic orbifolds An orbifold is a type of "singular manifold" that looks locally like the quotient of a manifold by a finite group. Standard geometric quantization provides a recipe for constructing a Hilbert space from a manifold with some additional structure; this can be used to construct example of strict deformation quantization. The project would be to extend geometric quantization to orbifolds.
Discrete models of quantum field theory Quantum field theory is difficult – in part because it involves infinitely many infinitedimensional algebras. If spacetime didn't have so many points, then it might be easier. Discrete versions of spacetime (such as causal sets) have been seriously considered as models for the universe. However, the idea of this project is to use discrete spacetime as a setting for "toy" models of classical and quantum field theory.
Classical and quantum electrodynamics are very old subjects and have been studied extensively. However, it has not been clear how the former is obtained as a classical limit of the latter in radiation processes. Working with a student, Giles Martin (PhD, 2008), he established that the classical backreaction force on a radiating charged particle can be obtained as the classical limit from quantum electrodynamics (QED). He and Phil Walker (PhD, 2011) have calculated a quantum correction to the classical Larmor formula for the energy emitted from an accelerated charged particle. He is planning to extend his work on the semiclassical approximation in quantum field theory to radiation processes in curved spacetime and also apply it to gravitational radiation.
Quantum field theory in de Sitter spacetime, which is relevant to inflationary cosmology, is believed to solve various puzzles in the bigbang cosmology. Atsushi Higuchi has supervised four PhD students in this area. With Spyros Kouris (PhD, 2003) he worked on constructing the twoparameter family of covariant propagators for gravitational waves, which will be useful in studying the gravitational fluctuation in this spacetime. With Richard Weeks (PhD, 2005) he found that the longdistance quantum correlation of quantum gravitational fluctuation is weaker than some physicists have suspected. With Yen Cheong Lee (PhD, 2010) he demonstrated how the retarded Green’s function can be used in de Sitter spacetime – there had been some confusion about this in the literature – and started investigating interacting field theory in this spacetime. With Mir Faizal (PhD, 2011) he worked on some aspects of interacting quantum gauge theory and perturbative quantum gravity. He is planning to work further on various aspects of interacting quantum field theory in de Sitter spacetime in the next few years.
You will have the opportunity to investigate topics in nonrelativistic quantum mechanics with Stefan Weigert. The problems he is interested in are often motivated by questions currently addressed in quantum information.
In recent years, the properties of socalled mutually unbiased bases have attracted considerable interest in the quantum information community. Expressing complementarity of variables in quantum mechanics, they naturally give rise to fundamental questions about finite quantum mechanical systems, i.e. quantum systems accomodating a finite number of states. Recent PhD projects in this field have been based on analytic, numerical and computeraided calculations.
Paul Busch's main research interest is the development of the operational tools of quantum measurement theory and their application to the solution of conceptual problems and the modeling of practical measurement schemes. One strand of current work is concerned with structural aspects of finitedimensional quantum systems (qudits), specifically the search for measures of approximation and degrees of unsharpness of quantum observables. Possible topics for PhD projects include the question of the connection between approximate joint measurability and approximate quantum cloning and the implications of these and other quantum measurement limitations for quantum information processing. Another possible project area is that of relativistic quantum measurements (covariant collapse, localisation vs. causality).
Roger Colbeck works on quantum information theory and quantum foundations. Within quantum information theory, he works on quantum cryptography and quantum random number generation and the use of quantum and relativistic protocols for secure computations. He also works on new uncertainty relations formulated in terms of entropy. Much of his work connects quantum information and the foundations of quantum theory, for example, he has done work on the question of whether the world is random, and whether there could be theories that improve on the predictions of quantum mechanics. There are many exciting directions this work could go in, and prospective PhD students should indicate any preferences they may have on their application form.
This year there are several additional opportunities in York created by the York centre for Quantum Technologies and the Quantum Communications hub. See here for more information.
Visitors to the Mathematical Physics group
Visitor  Home institution  Visit dates  Host 

Professor Anatol Kirillov  RIMS, Kyoto University  June 14, 2015  June 17, 2015  Professor Maxim Nazarov 
Dr Tommaso Gentile  Istituto Nazionale di Fisica Nucleare, Italy  April 8, 2014  September 20, 2014  Professor Paul Busch 
Dr Dan McNulty  Department of Optics, Palacky University Olomouc, Czech Republic  February 17, 2014  March 14, 2014  Dr Stefan Weigert 
Dr Leon Loveridge  University of British Columbia, Department of Physics and Astronomy, Vancover, Canada  January 13, 2014  January 17, 2014  Professor Paul Busch 
Dr Roberto Beneduci  University of Calabria, Italy  December 16, 2013  December 20, 2013  Professor Paul Busch 
Dr Guido Bacciagaluppi  School of Divinity, History and Philosophy, University of Aberdeen  October 17, 2013  October 18, 2013  Professor Paul Busch 
Dr Alexis Roa Aguirre  Instituto de Física Teórica, UNESP, Brazil  September 30, 2013  September 30, 2014  Professor Ed Corrigan 
Professor Lawrence Ford  Tufts University, Massachusetts, USA  June 9, 2013  June 14, 2013  Professor Chris Fewster 
Professor Thomas Roman  Department of Mathematical Sciences, Central Connecticut Sate University, USA  June 9, 2013  June 20, 2013  Professor Chris Fewster 
Professor Rainer Verch  Universitaet Leipzig, Germany  May 13, 2013  May 18, 2013  Professor Chris Fewster 
Dr Marcus Appleby  Queen Mary, University of London  May 6, 2013  May 7, 2013  Professor Paul Busch 
Professor Ingemar Bengtsson  University of Stockholm, Sweden  April 30, 2013  May 8, 2013  Professor Paul Busch 
Dr Teiko Heinosaari  University of Turku, Finland  February 3, 2013  February 8, 2013  Professor Paul Busch 
Dr Roberto Beneduci  University of Calabria, Italy  January 21, 2013  February 2, 2013  Professor Paul Busch 
Dr Roger Colbeck  ETH Zurich, Switzerland  October 29, 2012  October 31, 2012  Professor Paul Busch 
Dr Andrei Babichenko  Weizmann Institute  September 1, 2012  March 31, 2013  Prof. Niall MacKay 
Dr Yuan Li  Shaanxi Normal University, People's Republic of China  September 1, 2012  August 31, 2013  Professor Paul Busch 
Professor Lawrence Ford  Tufts University, Massachusetts, USA  June 11, 2012  June 15, 2012  Professor Chris Fewster 
Dr Jukka Kiukas  University of Nottingham  June 6, 2012  June 7, 2012  Professor Paul Busch 
Professor Tirthankar Bhattacharyya  Indian Institute of Science, Bangalore  October 11, 2011  October 13, 2011  Professor Paul Busch 
Dr Roberto Beneduci  University of Calabria, Italy  October 1, 2011  July 31, 2012  Professor Paul Busch 
Professor Takayuki Miyadera  University of Kyoto, Japan  September 9, 2011  October 6, 2011  Professor Paul Busch 
Professor Dipankar Home  Bose Institute, Calcutta, India  August 15, 2011  August 17, 2011  Professor Paul Busch 
Dr Teiko Heinosaari  University of Turku, Finland  July 25, 2011  July 31, 2011  Professor Paul Busch 
Professor Lawrence Ford  Tufts University, Massachusetts, USA  June 10, 2011  June 20, 2011  Professor Chris Fewster 