Nov 21 (Thu)
14:00 MCS2068 G&TPhilipp Reiser (Fribourg): Positive Ricci curvature and connected sums
The connected sum operation is a simple but useful tool in
geometric topology to connect two given manifolds. However, if both
manifolds are equipped with Riemannian metrics of positive Ricci
curvature, it is surprisingly difficult to determine whether this
condition can be preserved under the connected sum. In this talk, I will
review previous work by Perelman and Burdick on this problem, and then
discuss a new construction for Riemannian metrics of positive Ricci
curvature on connected sums of certain fibre bundles.
Venue: MCS2068
Nov 22 (Fri)
13:00 MCS0001 HEPMXiang Zhao (EPFL): Gravity from Matrix Quantum Mechanics
In this talk, I will introduce the BFSS matrix quantum mechanics model and discuss its connection to holography and its subtle differences from usual AdS/CFT correspondence. Following that, I will present the BMN model, a supersymmetry-preserving mass deformation of the BFSS model. The strong coupling limit of the BMN model will be analysed, and the results compared with predictions from supergravity. Finally, I will also explain how to formulate the quantum mechanics bootstrap problem for the BMN model, leveraging input from supersymmetry localisation results.
Venue: MCS0001
Nov 25 (Mon)
14:00 MCS2068 ProbAvi Mayorcas (University of Bath): Large deviations for the Φ43 measure via Stochastic Quantisation
The Φ43 measure is one of the easiest non-trivial examples of a Euclidean quantum field theory (EQFT) whose rigorous construction in the 1970’s has been one of the celebrated achievements of the constructive QFT community. In recent years, progress in the field of singular stochastic PDEs, initially by the theory of regularity structures, has allowed to construct the Φ43 EQFT as the invariant measure of a previously ill-posed Langevin dynamics—a strategy originally proposed by Parisi and Wu (’81) under the name stochastic quantisation. In this talk, I will demonstrate that the same idea also allows for the transference of large deviation principles for the Φ43 dynamics, obtained by Hairer and Weber (’15), to the corresponding EQFT. Our strategy is inspired by earlier work of Sowers (’92) and Cerrai and Röckner (’05) for non-singular dynamics and potentially also applies to other EQFT measures. The talk is based on joint work with Tom Klose (University of Oxford).
Venue: MCS2068
Nov 26 (Tue)
14:00 MCS2068 APDEDavid Seifert (University of Newcastle): Rates of decay for operator semigroups and damped waves
Semigroup theory has long played a central role in the study of damped waves and other linear evolution equations. One of the most influential results of recent times has been a theorem due to Borichev and Tomilov (Math. Annalen, 2010), which yields optimal polynomial rates of decay for classical semigroup orbits provided the resolvent satisfies a corresponding polynomial estimate along the imaginary axis. In this talk I shall present an extension of the Borichev-Tomilov theorem beyond the purely polynomial case to a much larger class of resolvent bounds. This result is optimal in several ways. I shall also give examples illustrating how the abstract theory can be used to obtain sharp rates of energy decay in wave equations subject to different types of damping.
Venue: MCS2068
Nov 28 (Thu)
14:00 MCS2068 G&TJohn Hunton (Durham): A complete invariant for flow spaces
By a "flow space" I mean a compact, connected 1 dimensional
space equipped with a non-constant minimal action by the real line
(i.e., every orbit is dense in the whole space). Apart from the trivial
case of the circle, such spaces naturally occur as fundamental objects
in 1d topological dynamics \u2013 for example the Denjoy continua, any
aperiodic minimal set of a flow on a higher genus surface, and any
aperiodic minimal set of the suspension of a subshift, such as in the
Lorenz template models of the Lorenz attractor. A "flow equivalence" of
such spaces is a homeomorphism between them that preserves the
directions of the flows. I will present a complete invariant of flow
spaces up to flow equivalence. This is joint work with Alex Clark (QMUL).
Venue: MCS2068
Click on title to see abstract.
Back to Homepage
Click on series to expand.
Usual Venue: MCS3070
Contact: sabine.boegli@durham.ac.uk
Nov 26 14:00 David Seifert (University of Newcastle): Rates of decay for operator semigroups and damped waves
Semigroup theory has long played a central role in the study of damped waves and other linear evolution equations. One of the most influential results of recent times has been a theorem due to Borichev and Tomilov (Math. Annalen, 2010), which yields optimal polynomial rates of decay for classical semigroup orbits provided the resolvent satisfies a corresponding polynomial estimate along the imaginary axis. In this talk I shall present an extension of the Borichev-Tomilov theorem beyond the purely polynomial case to a much larger class of resolvent bounds. This result is optimal in several ways. I shall also give examples illustrating how the abstract theory can be used to obtain sharp rates of energy decay in wave equations subject to different types of damping.
Venue: MCS2068
Usual Venue: MCS2068
Contact: andrew.krause@durham.ac.uk
No upcoming seminars have been scheduled (not unusual outside term time).
Usual Venue: OC218
Contact: mohamed.anber@durham.ac.uk
For more information, see HERE.
No upcoming seminars have been scheduled (not unusual outside term time).
Usual Venue: MCS3052
Contact: andrew.krause@durham.ac.uk
No upcoming seminars have been scheduled (not unusual outside term time).
Usual Venue: MCS2068
Contact: martin.p.kerin@durham.ac.uk
Nov 21 14:00 Philipp Reiser (Fribourg): Positive Ricci curvature and connected sums
The connected sum operation is a simple but useful tool in
geometric topology to connect two given manifolds. However, if both
manifolds are equipped with Riemannian metrics of positive Ricci
curvature, it is surprisingly difficult to determine whether this
condition can be preserved under the connected sum. In this talk, I will
review previous work by Perelman and Burdick on this problem, and then
discuss a new construction for Riemannian metrics of positive Ricci
curvature on connected sums of certain fibre bundles.
Venue: MCS2068
Nov 28 14:00 John Hunton (Durham): A complete invariant for flow spaces
By a "flow space" I mean a compact, connected 1 dimensional
space equipped with a non-constant minimal action by the real line
(i.e., every orbit is dense in the whole space). Apart from the trivial
case of the circle, such spaces naturally occur as fundamental objects
in 1d topological dynamics \u2013 for example the Denjoy continua, any
aperiodic minimal set of a flow on a higher genus surface, and any
aperiodic minimal set of the suspension of a subshift, such as in the
Lorenz template models of the Lorenz attractor. A "flow equivalence" of
such spaces is a homeomorphism between them that preserves the
directions of the flows. I will present a complete invariant of flow
spaces up to flow equivalence. This is joint work with Alex Clark (QMUL).
Venue: MCS2068
Dec 05 14:00 Diego Corro (Cardiff): TBA
Jan 16 14:00 Patrick Wood (Durham): TBA
Jan 30 14:00 Ana García Lecuona (Glasgow): TBA
Feb 06 14:00 Anthea Monod (Imperial): TBA
Feb 13 14:00 JeongHyeong Park (Sungkyunkwan University): TBA
Usual Venue: MCS0001
Contact: silvia.nagy@durham.ac.uk,enrico.andriolo@durham.ac.uk,tobias.p.hansen@durham.ac.uk
Nov 22 13:00 Xiang Zhao (EPFL): Gravity from Matrix Quantum Mechanics
In this talk, I will introduce the BFSS matrix quantum mechanics model and discuss its connection to holography and its subtle differences from usual AdS/CFT correspondence. Following that, I will present the BMN model, a supersymmetry-preserving mass deformation of the BFSS model. The strong coupling limit of the BMN model will be analysed, and the results compared with predictions from supergravity. Finally, I will also explain how to formulate the quantum mechanics bootstrap problem for the BMN model, leveraging input from supersymmetry localisation results.
Venue: MCS0001
Nov 29 13:00 Romain Ruzziconi (Oxford University): Carrollian holography from the flat limit of AdS/CFT
Carrollian holography suggests that gravity in four-dimensional asymptotically flat spacetime is dual to a three-dimensional Carrollian CFT living at null infinity. I will review this approach to flat space holography and its connection to celestial holography. I will explain how massless scattering amplitudes in the bulk can be reformulated in terms of Carrollian CFT correlators at null infinity, known as Carrollian amplitudes. Then, I will argue that Carrollian holography is naturally related to AdS/CFT through a correspondence between flat limit in the bulk and Carrollian limit at the boundary. More specifically, I will show that Carrollian amplitudes are the natural objects arising in the flat limit of holographic correlators in AdS.
This presentation will be mainly based on:
https://arxiv.org/abs/2312.10138
https://arxiv.org/abs/2406.19343
Venue: MCS0001
Dec 06 13:00 Andrea Antinucci (SISSA): TBA
Dec 13 13:00 Nicole Righi (King's College London): TBA
Usual Venue: MCS2068
Contact: kohei.suzuki@durham.ac.uk
Nov 25 14:00 Avi Mayorcas (University of Bath): Large deviations for the Φ43 measure via Stochastic Quantisation
The Φ43 measure is one of the easiest non-trivial examples of a Euclidean quantum field theory (EQFT) whose rigorous construction in the 1970’s has been one of the celebrated achievements of the constructive QFT community. In recent years, progress in the field of singular stochastic PDEs, initially by the theory of regularity structures, has allowed to construct the Φ43 EQFT as the invariant measure of a previously ill-posed Langevin dynamics—a strategy originally proposed by Parisi and Wu (’81) under the name stochastic quantisation. In this talk, I will demonstrate that the same idea also allows for the transference of large deviation principles for the Φ43 dynamics, obtained by Hairer and Weber (’15), to the corresponding EQFT. Our strategy is inspired by earlier work of Sowers (’92) and Cerrai and Röckner (’05) for non-singular dynamics and potentially also applies to other EQFT measures. The talk is based on joint work with Tom Klose (University of Oxford).
Venue: MCS2068
Dec 02 14:00 Hiroshi Kawabi (Oxford University, Keio University): Stochastic quantisation associated with the exp(Φ)_{2}-quantum field model
We consider a quantum field model with exponential interactions on the two-dimensional torus, which is called the exp(Φ)_{2}-quantum field model or Hoegh-Krohn’s model. In this talk, we discuss the stochastic quantisation of this model driven by the space-time white noise. Combining key properties of Gaussian multiplicative chaos with a method for singular SPDEs, we construct a unique time-global solution to the corresponding parabolic stochastic quantisation equation in the full L^{1}-regime 𝛼^{2}<8π of the charge parameter 𝛼. We also identify the solution with an infinite dimensional diffusion process constructed by the Dirichlet form approach. The main part of this talk is based on joint work with Masato Hoshino (Osaka University) and Seiichiro Kusuoka (Kyoto University).
Venue: MCS2068
Dec 09 14:00 Noe Kawamoto (NCCU, Taiwan):
Usual Venue: MCS0001
Contact: raphael.zentner@durham.ac.uk
Dec 02 13:00 Christopher Judge (Indiana University Bloomington): TBA
Jan 20 13:00 Gabriel Fuhrmann (Durham University): TBA
Mar 10 13:00 Karen Vogtmann (University of Warwick): TBA
Mar 17 13:00 Andras Juhasz (University of Oxford): TBA
