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SUMMARY:Roland Bittleston (Perimeter Institute)
DTSTART:20230615T003000Z
DTEND:20230615T013000Z
DTSTAMP:20260404T110643Z
UID:nmps/1
DESCRIPTION:Title: Overview of Classical and Quantum Integrability in Four Dimensions
\nby Roland Bittleston (Perimeter Institute) as part of Nagoya Math-Phys S
eminar\n\n\nAbstract\nThis talk will review recent progress by a number of
groups in understanding classical and quantum integrable models in four d
imensions. This has been achieved by exploiting twistor methods. After a s
hort introduction to twistors\, I will introduce some of the simplest exam
ples of 4d theories with twistor uplifts: self-dual Yang-Mills and the 4d
WZW model. I then plan to touch on a number of topics including: the conne
ction to 4d Chern-Simons theory\, quantization of these theories on twisto
r space\, their hidden symmetry algebras (also known as celestial chiral a
lgebras) and finally the twistor string.\n
LOCATION:https://stable.researchseminars.org/talk/nmps/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Roland Bittleston (Perimeter Institute)
DTSTART:20230616T003000Z
DTEND:20230616T013000Z
DTSTAMP:20260404T110643Z
UID:nmps/2
DESCRIPTION:Title: Classical and Quantum Integrability in Self-Dual Gravity\nby Rolan
d Bittleston (Perimeter Institute) as part of Nagoya Math-Phys Seminar\n\n
\nAbstract\nThis talk will concentrate on an intriguing example of a 4d in
tegrable theory: self-dual gravity. I will explain how its classical integ
rability is realised in the existence of an infinite dimensional hidden sy
mmetry algebra\, or celestial chiral algebra. This governs the universal h
olomorphic surface defect which can couple to the twistor uplift of self-d
ual gravity. At the quantum level\, this twistor uplift is anomalous and t
he quantum corrected chiral algebra fails to be associative. I will presen
t a number of methods of cancelling the anomaly\, leading to consistent qu
antum corrected hidden symmetry algebras. Finally\, I will explore how thi
s story is modified on one of the simplest non-trivial examples of a self-
dual Ricci flat background: the Eguchi-Hanson gravitational instanton.\n\n
This talk is based on collaborations with Simon Heuveline\, Atul Sharma an
d David Skinner.\n
LOCATION:https://stable.researchseminars.org/talk/nmps/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Atul Sharma (Harvard University)
DTSTART:20230721T003000Z
DTEND:20230721T013000Z
DTSTAMP:20260404T110643Z
UID:nmps/3
DESCRIPTION:Title: Burns holography\nby Atul Sharma (Harvard University) as part of N
agoya Math-Phys Seminar\n\n\nAbstract\nI will describe a top-down example
of celestial holography\, based on recent work with Costello and Paquette.
Our duality relates certain models of self-dual gauge theory and conforma
l gravity\, placed on an asymptotically flat four-dimensional spacetime ca
lled Burns space\, to a two-dimensional chiral algebra living on D1 branes
in a topological string theory on twistor space.\n
LOCATION:https://stable.researchseminars.org/talk/nmps/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Frank Nijhoff (University of Leeds)
DTSTART:20230914T080000Z
DTEND:20230914T090000Z
DTSTAMP:20260404T110643Z
UID:nmps/4
DESCRIPTION:Title: Lagrangian multiforms\, the Darboux-KP system and Chern-Simons theory
in infinite-dimensional space\nby Frank Nijhoff (University of Leeds)
as part of Nagoya Math-Phys Seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/nmps/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Francis Howard (Benin University)
DTSTART:20231019T080000Z
DTEND:20231019T090000Z
DTSTAMP:20260404T110643Z
UID:nmps/5
DESCRIPTION:Title: Particles and p－Adic Integrals of Spin(1/2): Spin Lie Group\, R(ρ\,
q)－gamma and R(ρ\, q)－ beta Functions\, Ghost and Applications\n
by Francis Howard (Benin University) as part of Nagoya Math-Phys Seminar\n
\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/nmps/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Artur Sergyeyev (Opava)
DTSTART:20231109T080000Z
DTEND:20231109T090000Z
DTSTAMP:20260404T110643Z
UID:nmps/6
DESCRIPTION:Title: Infinitely many new (3+1)-dimensional integrable systems from contact
geometry\nby Artur Sergyeyev (Opava) as part of Nagoya Math-Phys Semin
ar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/nmps/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Meer Ashwinkumar (University of Bern)
DTSTART:20231221T080000Z
DTEND:20231221T090000Z
DTSTAMP:20260404T110643Z
UID:nmps/7
DESCRIPTION:Title: Dualities and Discretizations of Integrable Quantum Field Theories fro
m 4d Chern-Simons Theory\nby Meer Ashwinkumar (University of Bern) as
part of Nagoya Math-Phys Seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/nmps/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yuri Suris
DTSTART:20240509T080000Z
DTEND:20240509T090000Z
DTSTAMP:20260404T110643Z
UID:nmps/8
DESCRIPTION:Title: E. Noether's variational symmetries and pluri-Lagrangian systems\n
by Yuri Suris as part of Nagoya Math-Phys Seminar\n\n\nAbstract\nWe analyz
e the relation of the notion of a pluri-Lagrangian system\, which recently
emerged in the theory\nof integrable systems\, to the classical notion of
variational symmetry\, due to E. Noether. For finite-dimensional (classic
al mechanical) systems we show that\, for any Lagrangian system with m com
muting variational symmetries\, one can construct a pluri-Lagrangian 1-for
m in the (m+1)-dimensional time\,\nwhose multi-time Euler-Lagrange equatio
ns coincide with the original system supplied with m commuting\nevolutiona
ry flows corresponding to the variational symmetries. For two-dimensional
hierarchies of\nLagrangian PDEs\, we show that if the flow of each PDE is
a variational symmetry of all others\, then there exists a pluri-Lagrangia
n 2-form for the hierarchy. The corresponding multi-time Euler–Lagrange
equations coincide with the original system supplied with commuting evolut
ionary flows induced by the variational symmetries.\n
LOCATION:https://stable.researchseminars.org/talk/nmps/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Junya Yagi (Tsinghua)
DTSTART:20240913T080000Z
DTEND:20240913T090000Z
DTSTAMP:20260404T110643Z
UID:nmps/9
DESCRIPTION:Title: 3D integrability in gauge theories\nby Junya Yagi (Tsinghua) as pa
rt of Nagoya Math-Phys Seminar\n\n\nAbstract\nThe Zamolodchikov tetrahedro
n equation is a fundamental relation for the integrability of 3D lattice m
odels in statistical mechanics\, playing a role similar to the Yang-Baxter
equation in 2D lattice models. I will discuss how solutions of the tetrah
edron equation arise from dualities of supersymmetric gauge theories.\n
LOCATION:https://stable.researchseminars.org/talk/nmps/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Richard Szabo
DTSTART:20250314T083000Z
DTEND:20250314T093000Z
DTSTAMP:20260404T110643Z
UID:nmps/10
DESCRIPTION:Title: Double copy of noncommutative gauge theory\nby Richard Szabo as p
art of Nagoya Math-Phys Seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/nmps/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mats Vermeeren
DTSTART:20250718T080000Z
DTEND:20250718T090000Z
DTSTAMP:20260404T110643Z
UID:nmps/11
DESCRIPTION:Title: Lagrangian multiforms and conservation laws\nby Mats Vermeeren as
part of Nagoya Math-Phys Seminar\n\n\nAbstract\nLagrangian multiform theo
ry is a variational principle for hierarchies of commuting differential eq
uations. Lagrangian 1-forms typically describe systems of commuting ODEs\,
Lagrangian 2-forms typically describe hierarchies of (1+1)-dimensional PD
Es\, and so on. Typical examples include soliton hierarchies such as the K
dV. In these examples\, there is a close relation between the existence of
a Lagrangian multiform and the fact that the flows are variational symmet
ries of each other.\n\n In this talk\, we give a number of examples of Lag
rangian multiforms that break this pattern. We will present Lagrangian 2-f
orms that can be interpreted as conservation laws for 3-dimensional PDEs.
In these examples\, the conservation Law does not arise via Noether's theo
rem from a known Lagrangian. Almost the opposite is true: the construction
of a Lagrangian multiform relies on the existence of a suitable conservat
ion Law for an equation that is not variational by itself.\n\nWe also give
additional examples of Lagrangian multiforms for dispersionless integrabl
e systems\, including some systems that arise via hydrodynamic reductions
of Plebanski's second heavenly equation.\n
LOCATION:https://stable.researchseminars.org/talk/nmps/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Vincent Caudrelier
DTSTART:20260116T080000Z
DTEND:20260116T090000Z
DTSTAMP:20260404T110643Z
UID:nmps/12
DESCRIPTION:Title: Classical Yang-Baxter equation\, Lagrangian multiforms and ultralocal
integrable hierarchies\nby Vincent Caudrelier as part of Nagoya Math-
Phys Seminar\n\n\nAbstract\nI will first review the main ideas of Lagrangi
an multiform theory which provides a variational framework for integrable
systems\, focusing on 1+1 dimensional models. The key idea is to encode va
riationally the compatibility of the flows in an integrable hierarchy by i
ntroducing a generalisation of standard Lagrangians and action functionals
\, and a corresponding generalisation of the principle of least action. \n
\nI will then present a systematic construction of Lagrangian multiforms f
or hierarchies of ultralocal field theories. The ''multitime'' Euler-Lagra
nge equations produce the infinite collection of flatness equations for th
e Lax connection. It is based on a few key (algebraic) ingredients\, the m
ain one being the classical r-matrix and the classical Yang-Baxter equatio
n. In particular\, the construction casts the classical Yang-Baxter in a v
ariational context for the first time. For simplicity of exposition\, I wi
ll focus on the simplest example of the so-called Ablowitz-Kaup-Newell-Seg
ur hierarchy which already contains all the essential features (classical
r-matrix\, generating formalism). I will then explain briefly how these fe
atures generalise to produce Lagrangian multiforms for many other (known a
nd new) hierarchies : e.g. Zakharov-Mikhailov\, Faddeev-Reshetikhin model\
, deformed sigma/Gross-Neveu models. Time permitting\, I will explain how
one can easily couple different hierarchies together to form new ones and
obtain the corresponding Lagrangian multiform.\n
LOCATION:https://stable.researchseminars.org/talk/nmps/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Skinner (Cambridge)
DTSTART:20260220T080000Z
DTEND:20260220T090000Z
DTSTAMP:20260404T110643Z
UID:nmps/13
DESCRIPTION:Title: Topological Strings on the Beach\nby David Skinner (Cambridge) as
part of Nagoya Math-Phys Seminar\n\n\nAbstract\nThe KP equation is a well
-known classical integrable system that describes shallow water waves in 2
+1 dimensions. While many integrable systems are known to arise from twist
or space\, the KP equation has long resisted this classification. Recently
\, following ideas of Costello\, the KP equation has been shown to arise f
rom a mixed topological-holomorphic Chern-Simons theory in 5d. This theory
comes complete with a chiral W-algebra and suggests that solitonic waves
correspond to holomorphic line bundles on non-commutative mini-twistor spa
ce.\n
LOCATION:https://stable.researchseminars.org/talk/nmps/13/
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