Triangle Seminars

December 2025

Wed
17 Dec 2025
TBA
📍 London
Marine De Clerck (Cambridge University)
Venue: KCL · Room: KINGS BLDG KIN 204 · Time: 14:00 · Type: Regular Seminar
Abstract:
TBA
Posted by: Andrew Svesko
Wed
10 Dec 2025
TBA
📍 London
Daniel Brennan
Venue: KCL · Room: KINGS BLDG KIN 204 · Time: 14:00 · Type: Regular Seminar
Abstract:
TBA
Posted by: Andrew Svesko
Tue
9 Dec 2025
TBA
📍 London
Rishi Mouland (Imperial College)
Venue: QMUL · Room: MB 503 Mathematics Seminar Room · Time: 14:00 · Type: Regular Seminar
Tue
9 Dec 2025
TBA
📍 London
Axel Kleinschmidt (AEI)
Venue: ICL · Room: H503 · Time: 14:30 · Type: Colloquium
Abstract:
TBA
Posted by: Sebastian Cespedes
Wed
3 Dec 2025
TBA
📍 London
Cyril Closset (Birmingham University)
Venue: ICL · Room: H503 · Time: 13:30 · Type: Regular Seminar

November 2025

Wed
26 Nov 2025
TBA
📍 London
Madalena Lemos (Durham University)
Venue: ICL · Room: H503 · Time: 13:30 · Type: Regular Seminar
Wed
26 Nov 2025
TBA
📍 London
Rodolfo Russo (Queen Mary University London)
Venue: KCL · Room: KINGS BLDG KIN 204 · Time: 14:00 · Type: Regular Seminar
Abstract:
TBA
Posted by: Andrew Svesko
Tue
25 Nov 2025
TBA
📍 London
Raphaela Wutte (University of Southampton)
Venue: QMUL · Room: MB 503 Mathematics Seminar Room · Time: 14:00 · Type: Regular Seminar
Tue
25 Nov 2025
TBA
📍 London
Emanuela Dimastrogiovani (Groeningen University)
Venue: ICL · Room: H503 · Time: 14:30 · Type: Colloquium
Abstract:
TBA
Posted by: Sebastian Cespedes
Tue
18 Nov 2025
TBA
📍 London
Bernardo Araneda (University of Edinburgh)
Venue: QMUL · Room: MB 503 Mathematics Seminar Room · Time: 14:00 · Type: Regular Seminar
Tue
18 Nov 2025
TBA
📍 London
Livia Ferro (University of Hertfordshire)
Venue: ICL · Room: H503 · Time: 14:30 · Type: Colloquium
Abstract:
TBA
Posted by: Sebastian Cespedes
Wed
12 Nov 2025
TBA
📍 London
Sameer Murthy (Kings College London)
Venue: ICL · Room: H503 · Time: 13:30 · Type: Regular Seminar
Wed
12 Nov 2025
TBA
📍 London
Laura Donnay (SISSA)
Venue: KCL · Room: KINGS BLDG KIN 204 · Time: 14:00 · Type: Regular Seminar
Abstract:
TBA
Posted by: Andrew Svesko
Tue
11 Nov 2025
TBA
📍 London
Dionysios Anninos (KCL)
Venue: ICL · Room: H503 · Time: 14:30 · Type: Colloquium
Abstract:
TBA
Posted by: Sebastian Cespedes
Mon
10 Nov 2025
Lonti: Introduction to Matrix Models (4/4)
📍 London
Fedor Levkovich-Maslyuk (City U.)
Venue: LIMS · Time: 10:30 · Type: Regular Seminar
Abstract:
Models of random matrices can be viewed as zero-dimensional analogs of usual field theory. Despite decades of exploration, matrix models remain at the forefront of intensive research, motivated by a rich web of connections to string theory, quantum gravity, integrability, Yang-Mills theory, combinatorics, geometry and representation theory. These lectures will present a pedagogical introduction to the subject.

​Lecture 1. Motivation and basic definitions. Hermitian matrix models: Feynman rules, ribbon graphs, large N genus expansion.
Lecture 2. Reduction to eigenvalues. Large N limit, Coulomb gas approach, saddle point equations.
Lecture 3. Continuum limit of saddle point equations. Eigenvalue density and spectral curve. Examples.
Lecture 4. Orthogonal polynomials. Relation to 2d gravity and phase transitions (sketch). Outlook: loop equations, topological recursion, integrability.
Posted by: Damian Galante
Wed
5 Nov 2025
TBA
📍 London
Alessandro Sfondrini (Padua University)
Venue: ICL · Room: H503 · Time: 13:30 · Type: Regular Seminar
Tue
4 Nov 2025
TBA
📍 London
António Antunes (LPENS)
Venue: QMUL · Room: MB 503 Mathematics Seminar Room · Time: 14:00 · Type: Regular Seminar
Tue
4 Nov 2025
TBA
📍 London
Aron Wall (University of Cambridge)
Venue: ICL · Room: H503 · Time: 14:30 · Type: Colloquium
Abstract:
TBA
Posted by: Sebastian Cespedes
Mon
3 Nov 2025
Lonti: Introduction to Matrix Models (3/4)
📍 London
Fedor Levkovich-Maslyuk (City U.)
Venue: LIMS · Time: 10:30 · Type: LonTI
Abstract:
Models of random matrices can be viewed as zero-dimensional analogs of usual field theory. Despite decades of exploration, matrix models remain at the forefront of intensive research, motivated by a rich web of connections to string theory, quantum gravity, integrability, Yang-Mills theory, combinatorics, geometry and representation theory. These lectures will present a pedagogical introduction to the subject.

​Lecture 1. Motivation and basic definitions. Hermitian matrix models: Feynman rules, ribbon graphs, large N genus expansion.
Lecture 2. Reduction to eigenvalues. Large N limit, Coulomb gas approach, saddle point equations.
Lecture 3. Continuum limit of saddle point equations. Eigenvalue density and spectral curve. Examples.
Posted by: Damian Galante

October 2025

Wed
29 Oct 2025
TBA
📍 London
Maxim Zabzine (Uppsala University)
Venue: ICL · Room: H503 · Time: 13:30 · Type: Regular Seminar
Wed
29 Oct 2025
TBA
📍 London
Toby Wiseman (Imperial College London)
Venue: KCL · Room: KINGS BLDG KIN 204 · Time: 14:00 · Type: Regular Seminar
Abstract:
TBA
Posted by: Andrew Svesko
Tue
28 Oct 2025
TBA
📍 London
Eleanor Hamilton (Universitat de les Illes Balears)
Venue: QMUL · Room: MB 503 Mathematics Seminar Room · Time: 14:00 · Type: Regular Seminar
Tue
28 Oct 2025
TBA
📍 London
Andre Bernevig (Princeton University)
Venue: ICL · Room: H503 · Time: 14:30 · Type: Colloquium
Abstract:
TBA
Posted by: Sebastian Cespedes
Mon
27 Oct 2025
Lonti: Introduction to Matrix Models (2/4)
📍 London
Fedor Levkovich-Maslyuk (City U.)
Venue: LIMS · Time: 10:30 · Type: Regular Seminar
Abstract:
Models of random matrices can be viewed as zero-dimensional analogs of usual field theory. Despite decades of exploration, matrix models remain at the forefront of intensive research, motivated by a rich web of connections to string theory, quantum gravity, integrability, Yang-Mills theory, combinatorics, geometry and representation theory. These lectures will present a pedagogical introduction to the subject.

​Lecture 1. Motivation and basic definitions. Hermitian matrix models: Feynman rules, ribbon graphs, large N genus expansion.
Lecture 2. Reduction to eigenvalues. Large N limit, Coulomb gas approach, saddle point equations.
Posted by: Damian Galante
Wed
22 Oct 2025
TBA
📍 London
Shinshei Ryu (Princeton University)
Venue: ICL · Room: H503 · Time: 13:30 · Type: Regular Seminar
Wed
22 Oct 2025
Hyperbolic Mass in 2+1 Dimensions
📍 London
Raphaela Wutte (University of Southampton)
Venue: KCL · Room: KINGS BLDG KIN 204 · Time: 14:00 · Type: Regular Seminar
Abstract:
Solutions to general relativity with a negative cosmological constant have received significant attention due to the conjectured AdS/CFT correspondence, a particularly well-understood example of which is exhibited in 2+1 dimensions. I will review known vacuum solutions to general relativity with a negative cosmological constant in 2+1 dimensions and discuss the difficulties in defining mass, which are resolved via minimisation using a positive energy theorem. I will present a gluing theorem for vacuum time-symmetric general-relativistic initial data sets in two spatial dimensions. By gluing two given time-symmetric vacuum initial data sets at conformal infinity, we obtain new time-symmetric vacuum initial data sets. I will sketch the derivation of the mass formulae of the resulting manifolds. Our gluing theorem yields complete manifolds with any mass aspect function, which are smooth except for one conical singularity.
Posted by: Andrew Svesko
Tue
21 Oct 2025
TBA
📍 London
Joydeep Chakravarty (McGill University)
Venue: QMUL · Room: MB 503 Mathematics Seminar Room · Time: 14:00 · Type: Regular Seminar
Tue
21 Oct 2025
Gravity in the era of Stage IV Surveys
📍 London
Alessandra Silvestri (Leiden University)
Venue: ICL · Room: H503 · Time: 14:30 · Type: Colloquium
Abstract:
Stage IV Large Scale Structure Surveys are ushering in a new
era of precision cosmology! In this talk, I will explore the effort to test gravity on cosmological
scales, highlighting the theoretical advancements aimed at constructing
an optimal framework. I will also touch on the synergy with
gravitational wave surveys. Additionally, I will provide a detailed
review of recent findings based on currently available data and conclude
with an outlook on the challenges and future prospects in this field.
Posted by: Sebastian Cespedes
Mon
20 Oct 2025
Lonti: Introduction to Matrix Models (1/4)
📍 London
Fedor Levkovich-Maslyuk (City U.)
Venue: LIMS · Time: 10:30 · Type: Regular Seminar
Abstract:
Models of random matrices can be viewed as zero-dimensional analogs of usual field theory. Despite decades of exploration, matrix models remain at the forefront of intensive research, motivated by a rich web of connections to string theory, quantum gravity, integrability, Yang-Mills theory, combinatorics, geometry and representation theory. These lectures will present a pedagogical introduction to the subject.

​Lecture 1. Motivation and basic definitions. Hermitian matrix models: Feynman rules, ribbon graphs, large N genus expansion.
Posted by: Damian Galante
Fri
17 Oct 2025
Grothendieck & ’t Hooft: Dessins d’Enfant from AdS/CFT
📍 London
Edward Mazenc (ETH, Zurich)
Venue: LIMS · Room: LIMS, Royal Institution · Time: 01:30 · Type: Colloquium
Abstract:
In the later part of his life, Grothendieck became fascinated by the fact that certain simple graphs can encode holomorphic maps to the sphere. He called them dessins d’enfants — “children’s drawings.”
Meanwhile, over fifty years ago, ’t Hooft observed that the 1/N expansion in gauge theory closely mirrors the genus expansion in string theory, suggesting a relation between Feynman diagrams and string worldsheets.
I will discuss how recent efforts to derive the AdS/CFT correspondence unite these two perspectives: Grothendieck’s surprise emerges as the simplest instance of gauge/string duality.
Posted by: Yang-Hui He
Fri
17 Oct 2025
Phases of 2d Gauge Theories and Symmetric Mass Generation
📍 London
Rishi Mouland (Imperial ICL)
Venue: LIMS · Room: LIMS 2F seminar room · Time: 11:00 · Type: Regular Seminar
Abstract:
We study the dynamics and phase structure of Abelian gauge theories in d=1+1 dimensions. These include U(1) gauge theory coupled to a scalar and a fermion, as well as the two-flavour Schwinger model with different charges. Both theories exhibit a surprisingly rich phase diagram as masses are varied, with both c=1 and c=1/2 critical lines or points. We build up to the study of 2d chiral gauge theories, which hold particular interest because they provide a mechanism for symmetric mass generation, a phenomenon in which fermions become gapped without breaking chiral symmetries.
Posted by: JUVEN WANG
Thu
16 Oct 2025
Gravity from Entropy
📍 London
Ginestra Bianconi (QMUL)
Venue: QMUL · Room: 610, GO Jones · Time: 14:00 · Type: Regular Seminar
Abstract:
Gravity is derived from an entropic action coupling matter fields with geometry called Gravity from Entropy action [1]. The fundamental idea is to relate the metric of Lorentzian spacetime to a quantum operator, playing the role of a renormalizable effective density matrix and to describe the matter fields topologically, according to a Dirac-Kähler formalism, as the direct sum of a 0-form, a 1-form and a 2-form. While the geometry of spacetime is defined by its metric, the matter fields can be used to define an alternative metric, the metric induced by the matter fields and curvature. The proposed Gravity from Entropy (GfE) action is associated to a Lagrangian given by a novel geometric quantum relative entropy (GQRE) between the metric of spacetime and the metric induced by the matter fields and curvature which capture the entanglement between geometric degrees of freedom of spacetime. The modified Einstein equations obtained from this action reduce to the Einstein equations with zero cosmological constant in the regime of low coupling. By introducing the G-field, which acts as a set of Lagrangian multipliers, and interpreting it a physical and measurable field, the proposed entropic action reduces to a dressed Einstein-Hilbert action with an emergent positive cosmological constant only dependent on the G-field. The obtained equations of modified gravity remain second order in the metric and in the G-field. Interestingly the GfE action when calculated on Schwarzschild metric allows us to derive from first principles the area law for black holes with large Schwarzschild radius [2]. A canonical quantization of this field theory could bring new insights into quantum gravity while further research might clarify the role that the G-field could have for dark matter.

[1] Bianconi, G., 2025. Gravity from entropy. Physical Review D, 111(6), p.066001.
[2] Bianconi, G., 2025. The quantum relative entropy of the Schwarzschild black hole and the area law. Entropy, 27(3), p.266.
Posted by: Nathan Moynihan
Thu
16 Oct 2025
Symmetry constraints on defects and scattering amplitudes
📍 London
Christian Copetti (Oxford University)
Venue: LIMS · Room: LIMS, Royal Institution · Time: 14:00 · Type: Regular Seminar
Abstract:
Symmetry is a powerful organizing principle, allowing for all-order predictions about the behaviour of quantum systems. In this talk I explain how (generalized) symmetries act on boundary conditions and defects, and use these ideas to constrain fundamental properties of (1+1)d scattering amplitudes, such as crossing symmetry, and screening of UV defects by bulk degrees of freedom.
Posted by: Evgeny Sobko
Wed
15 Oct 2025
Towards quantum computing strongly-interacting systems with quantum link gauge theories 
📍 London
Debasish Banerjee (University of Southampton)
Venue: QMUL · Room: Eng: 2.16 · Time: 11:30 · Type: Regular Seminar
Abstract:
The development in quantum technologies is matched by an equal energetic activity in formulations of quantum field theories, especially as quantum many-body Hamiltonians, suitable for implementation in quantum simulation and computers. In this talk, we discuss the quantum link formulation of lattice gauge theories, which has not only enabled successful synergy between particle and condensed matter physics, but have also pointed towards the existence of quantum scars which violate the eigenstate thermalization hypothesis and resist thermalization under unitary dynamics. Abelian quantum link models have also been implemented in quantum simulators and computers.
Posted by: João Vilas Boas
Wed
15 Oct 2025
Supercurrents and (partial) supersymmetry in 2d adjoint QCD and its generalizations
📍 London
Silviu Pufu (Princeton University)
Venue: CITY · Room: ELG03 · Time: 15:00 · Type: Triangular Seminar
Abstract:
The 1+1-dimensional adjoint QCD theory (namely SU(N) gauge theory coupled to a Majorana fermion in the adjoint representation of the gauge group) has the curious property that at a certain non-zero ratio of the fermion mass to the gauge coupling, it exhibits (1, 1) supersymmetry. I will shed some new light onto the supersymmetry of 2d adjoint QCD using several analytical and numerical methods, including the construction of a gauge-invariant, Lorentz-covariant supercurrent, whose conservation relies on the presence of a quantum anomaly. Lastly, I will discuss generalizations of the adjoint QCD theory that exhibit supersymmetric sectors.
Posted by: Charles Thull
Wed
15 Oct 2025
Precision holography for Dp-branes
📍 London
Nikolay Bobev (KU Leuven)
Venue: CITY · Room: ELG03 · Time: 16:30 · Type: Triangular Seminar
Abstract:
I will discuss precision holography for the non-conformal SYM theories arising on the worldvolume of coincident Dp-branes. I will show how the free energy of the planar SYM theory on the round sphere and the expectation values of fundamental BPS Wilson loops can be computed explicitly by utilizing supersymmetric localization. I will then present a class of supergravity backgrounds that capture the backreaction of spherical Dp-branes and provide a holographic description of the SYM theory. I will show that the supergravity calculations of the free energy and the Wilson loop expectation value are in precise agreement with the supersymmetric localization results. Finally, I will exploit the scaling similarity property of the Dp-brane supergravity solutions to derive simple Witten diagram rules for the calculation of n-point correlation functions and will show how to explicitly compute 2pt- and 3pt-functions. This leads to explicit results of the 2pt- and 3pt-functions of scalar BPS operators in the planar strongly-coupled SYM theory, including the cases of the BFSS model and the 3d maximally supersymmetric YM theory, that could be tested using lattice QFT methods.
Posted by: Charles Thull
Tue
14 Oct 2025
Neural Networks for Theoretical Calculations
📍 London
Daniel Maitre (Durham)
Venue: ICL · Room: H503 · Time: 14:30 · Type: Colloquium
Abstract:
Machine learning is transforming the way many many aspect of particle physics research is pursued. In this talk I will show a few different ways in which neural networks can be leveraged to make theoretical calculations more efficient and allow it to leverage the newest hardware and software developments.
Posted by: Sebastian Cespedes
Thu
9 Oct 2025
A fresh look at the Froissart bound
📍 London
Andrea Guerrieri (City University of London)
Venue: QMUL · Room: 610, GO Jones · Time: 14:00 · Type: Regular Seminar
Abstract:
The Froissart bound is the most celebrated result of the "analytic S-matrix" program.
It sets an absolute upper limit on total cross-sections at asymptotically high energies in any relativistic quantum theory. In this talk I will discuss an alternative version of this problem and derive rigorous bounds on the cross-section at finite energy, combining analytic techniques and non-perturbative S-matrix bootstrap. I will then discuss the amplitude that saturates our bounds, highlighting its distinctive and rather peculiar properties and connecting them with ancient expectations physicists had on non-perturbative growing amplitudes.
Posted by: Nathan Moynihan
Wed
8 Oct 2025
An integrable sector for the membrane
📍 London
David Osten (U. Wroclaw)
Venue: ICL · Room: H503 · Time: 13:30 · Type: Regular Seminar
Abstract:
In contrast to string sigma models which are well-known to be (classically) integrable in certain backgrounds, most famously flat space or AdS(5) x S(5), the same is not true for the membrane sigma model. Reasons for this are the non-trivial gravity on the world-volume but also the rarity of three-dimensional integrable field theories in general. Here, I will present the novel observation that a certain decoupling limit of the membrane in certain backgrounds will lead to an integrable model, the Manakov-Zakharov-Ward model – a known three-dimensional, but non-relativistic, integrable field theory. As an example of a supergravity background in which this limit is possible is the 11d uplift of the pure NS-NS AdS(3) x S(3) x T(4) background.
Posted by: Jesse van Muiden
Tue
7 Oct 2025
[Postponed to 18 November] Resurgent symmetry of quantum mirror curves
📍 South East
Claudia Rella (IHES)
Venue: SOTON · Room: Avenue Campus 65/1097 · Time: 00:00 · Type: AGP
Abstract:
This seminar will now take place on 18 November
Posted by: Ömer Gürdoğan
Tue
7 Oct 2025
Sharp Transitions for Subsystem Complexity
📍 London
Andreas Karch (University of Texas)
Venue: ICL · Room: H503 · Time: 14:30 · Type: Colloquium
Abstract:
The circuit complexity of time-evolved pure quantum states
grows linearly in time for an exponentially long time. This behavior has
been proven in certain models, is conjectured to hold for generic
quantum many-body systems, and is believed to be dual to the long-time
growth of black hole interiors in AdS/CFT. Achieving a similar
understanding for mixed states remains an important problem. We
demonstrate that holography predicts several sharp transitions in the
time evolution of subsystem complexity and show that at least some of
these transitions are also realized in random quantum circuits.
Posted by: Sebastian Cespedes
Fri
3 Oct 2025
Wall-crossing and scattering diagrams in geometry and beyond.
📍 London
Mark Gross (Cambridge)
Venue: LIMS · Room: LIMS, Royal Institution · Time: 14:00 · Type: Colloquium
Abstract:
I will discuss the notion of scattering diagrams, which encode often very complex data of wall-crossing for various kinds of geometric problems. These originally originated in work of Kontsevich-Soibelman, but have been found to occur naturally in many different contexts, from mirror symmetry, cluster algebras, wall-crossing for moduli spaces of sheaves, and theoretical physics.
Posted by: Yang-Hui He
Fri
3 Oct 2025
Integrable models, spin and statistics
📍 London
Alessandro Torrielli (University of Surrey)
Venue: LIMS · Room: LIMS, Royal Institution · Time: 15:30 · Type: Regular Seminar
Abstract:
Integrable models in 1+1 dimensions allows for exact solutions of their scattering problems, and often a complete derivation of the spectrum by means of algebraic methods. However, we rarely stop and wonder what the particles which we are scattering really are. In such low dimensionality, bosons, fermions, spin and statistics are actually far stranger than in our 3+1 dimensional world, and interesting phenomena are possible. We will discuss some generalities about spin and statistics in 1+1 dimensions, and then delve into one manifestation of this strange behaviour in AdS_3 string theory.
Posted by: Evgeny Sobko
Wed
1 Oct 2025
Integrability without Elastic Scattering
📍 London
Sibylle Driezen (ETH)
Venue: ICL · Room: H503 · Time: 13:30 · Type: Regular Seminar
Abstract:
Integrability provides a rare tool for accessing strongly coupled quantum field theories. To extend our understanding, it is important to study cases where the integrable structure departs significantly from known examples. I will discuss recent work on Drinfel’d twists of the Jordanian type in the spin chain formulation of the AdS_5 x S^5 superstring, which can be interpreted as spin chain avatars of worldsheet non-abelian T-duality. On the string side these deformations are Lax integrable, yet they lead to particle production, raising sharp questions about the scope and fate of integrability studies based on factorised and elastic S-matrices. From the spin-chain perspective, however, a different picture emerges: the natural eigenstates are organised not by particle number but by a residual non-Cartan symmetry. In this basis the spectrum follows from a simple Baxter equation, which we show to agree with (semi-)classical string energies computed from the algebraic curve. This provides not only the first evidence for a non-abelian deformed AdS/CFT duality (which is relevant for non-AdS holography), but also highlights a broader lesson: particle production need not signal the end of integrability, but may instead point to new forms in which it survives.
Posted by: Jesse van Muiden
Wed
1 Oct 2025
Quantum Gravity in Near-Extremal Black Holes
📍 London
Roberto Emparan (University of Barcelona)
Venue: KCL · Room: KINGS BLDG KIN 204 · Time: 14:00 · Type: Regular Seminar
Abstract:
Recent developments have revealed that black holes near extremality exhibit large quantum fluctuations in their geometry, marking a controllable breakdown of semiclassical quantum field theory in curved spacetime. In this talk, I will discuss how these fluctuations can be revealed through scattering waves off the black hole. In particular, we find that extremely cold black holes become transparent to low-frequency light or gravitational radiation. These effects provide concrete signatures of quantum gravity at play in near-extremal regimes.
Posted by: Andrew Svesko

September 2025

Tue
30 Sep 2025
Negative Energy
📍 London
Stefan Hollands (Leipzig University)
Venue: ICL · Room: H503 · Time: 14:30 · Type: Colloquium
Abstract:
Ordinarily, the actual energy is not physically significant but only energy differences are. But in general relativity, the absolute energy (density) appears on the right side of the Einstein equations as a component of the stress tensor. In this colloquium I explore how negative energy densities are thereby related to exotic phenomena such as warp drive spacetimes or wormholes. Quantum fluctuations enable negative energies and can be tiny, e.g. in the halos of black holes, or astronomical, e.g. inside black holes. In many interesting cases, the laws of physics limit the amount of possible negative energy, and such laws can be seen as a fundamental bridge between gravity and quantum information..
Posted by: Sebastian Cespedes
Thu
25 Sep 2025
Trans-IR flows and BKL dynamics in AdS black holes
📍 London
Ayan Kumar Patra
Venue: QMUL · Room: Seminar Room, School of Mathematics · Time: 14:00 · Type: Exceptional Seminar
Abstract:
The interior of asymptotically AdS black holes provides a setting where one can naturally extend the notion of holographic RG flows past their conventional infrared fixed points. In this talk, I will describe how these extended “trans-IR” flows provide a unique framework for capturing gravitational dynamics behind the horizon, especially as one approaches a spacelike singularity. Near the singularity, the geometry enters a regime governed by the BKL conjecture and characterized by a sequence of Kasner epochs and eras. To get a handle on the degrees of freedom involved in this evolution, I will introduce a monotonic function, known as the thermal a-function, which tracks the flow into the trans-IR region. With this function, I will show that the full sequence of Kasner epochs and eras can be effectively captured, and the degrees of freedom thin out and ultimately vanish at the trans-IR fixed point.
Posted by: Alan Rios Fukelman
Thu
25 Sep 2025
Bootstrapping Compton Amplitudes with Colour-Kinematics
📍 London
Andres Luna (NBI Copenhagen)
Venue: QMUL · Room: 610, GO Jones · Time: 14:00 · Type: Regular Seminar
Abstract:
In this talk, I will review the arbitrary-spin theory introduced in 2005.03071 to model spinning black holes in the post-Minkowskian approximation, and describe a procedure to systematically obtain Compton-like amplitudes in it, exploiting their factorization properties, and colour-kinematics duality. I will furthermore comment on the constraining of Wilson coefficients for arbitrary spinning bodies and its relation to colour-kinematic duality. This talk is based on 2503.22597.
Posted by: Nathan Moynihan
Thu
25 Sep 2025
Gravity from entropy
📍 London
Ginestra Bianconi (QML)
Venue: LIMS · Room: LIMS, Royal Institution · Time: 14:00 · Type: Regular Seminar
Abstract:
Gravity is derived from an action given by the geometrical quantum relative entropy coupling matter fields with geometry. The fundamental idea is to relate the metric of Lorentzian spacetime to a quantum operator, playing the role of an renormalizable effective density matrix and to describe the matter fields topologically, according to a Dirac-Kähler formalism, as the direct sum of a 0-form, a 1-form and a 2-form. While the geometry of spacetime is defined by its metric, the matter fields can be used to define an alternative metric, the metric induced by the matter fields, which geometrically describes the interplay between spacetime and matter. The proposed entropic action is the geometric quantum relative entropy between the metric of spacetime and the metric induced by the matter fields. The modified Einstein equations obtained from this action reduce to the Einstein equations with zero cosmological constant in the regime of low coupling. By introducing the G-field, which acts as a set of Lagrangian multipliers, the proposed entropic action reduces to a dressed Einstein-Hilbert action with an emergent small and positive cosmological constant only dependent on the G-field. The obtained equations of modified gravity remain second order in the metric and in the G-field. A canonical quantization of this field theory could bring new insights into quantum gravity while further research might clarify the role that the G-field could have for dark matter.

We furthermore show that the geometrical quantum relative entropy associated to the Schwarzschild metric, which provides an approximate solution of the modified gravity equations, follows the area law for large Schwarzschild radius.



Bianconi, G., 2025. Gravity from entropy. Physical Review D, 111(6), p.066001.

Bianconi, G., 2025. The quantum relative entropy of the Schwarzschild black hole and the area law. Entropy, 27(3), p.266.
Posted by: Yang-Hui He
Wed
24 Sep 2025
Quantum dynamics meets quantum information
📍 London
Alexey Milekhin (University of Kentucky)
Venue: LIMS · Room: LIMS, Royal Institution · Time: 14:00 · Type: Regular Seminar
Abstract:
Quantum computers have the potential to revolutionize both quantum simulations and classical computations. Rapid advancements in quantum hardware has not only introduced new opportunities but also posed significant theoretical challenges in understanding quantum dynamics. These developments highlight the need for benchmarking models—interacting many-body systems that can be solved exactly or numerically to assess the capabilities of quantum processors. In this talk, I will discuss powerful theoretical tools to address these challenges, focusing on the Sachdev–Ye–Kitaev (SYK) model and the emerging framework of entanglement in time, an information-theoretic approach designed to probe dynamical properties of quantum systems.
Posted by: Evgeny Sobko
Mon
22 Sep 2025
Dimensional Transmutation and Confinement in Various Models
📍 London
Igor Klebanov (Princeton University)
Venue: KCL · Room: KINGS BLDG KIN 205(Nash Lecture Theatre) · Time: 11:00 · Type: Exceptional Seminar
Abstract:
The talk will begin with a brief review of Quantum Chromodynamics (QCD) and the Confinement problem. Lattice Gauge Theory (LGT) provides a non-perturbative formulation of QCD, which has led to good numerical results for the low-lying hadron spectra. Yet, an analytical understanding of QCD is not available. I will then discuss several gauge theories which have some of the key features of QCD. One of them is based on the gauge/gravity duality and is described by the warped deformed conifold background of type IIB string theory. This theory exhibits confinement, and the quark-antiquark potential is similar to that found in LGT.

The 1+1 dimensional gauge theories have also served as useful models of quark confinement. I will revisit the classic Schwinger model and its lattice Hamiltonian formulation. A mass shift between the lattice and continuum definitions of mass, which is motivated by chiral symmetry, is shown to lead to improved results. I will also present the zero-temperature phase diagram of the two-flavor Schwinger model at theta=pi, which exhibits dimensional transmutation and spontaneous breaking of charge conjugation. Finally, I will discuss the 2D SU(N) gauge theory coupled to an adjoint multiplet of Majorana fermions. This model has a rich topological structure. I will introduce a Hamiltonian lattice approach to this gauge theory, in which one can compute the spectrum, the string tension, and other observables. The talk will end with some surprising exact results for this model.
Posted by: Andreas Stergiou
Thu
18 Sep 2025
Extracting spinning two-body observables from S-matrix
📍 London
Canxin Shi (Institute of Theoretical Physics, CAS (Beijing))
Venue: QMUL · Room: G. O. Jones Building, Room 610 · Time: 13:30 · Type: Regular Seminar
Abstract:
High-precision prediction of the two-body problem is at the center of gravitational-wave physics. I will present a novel method for extracting observables for two-body scattering systems from a set of generating functions, with full spin dependence. The approach uses the classical limit of the logarithm of the quantum S-matrix as generating functions. The 4-point matrix element of \(\log(S)\) gives the radial action, corresponding to conservative effects, whereas the higher-point contributions encode radiative information. The observables, such as momentum impulse, orbital angular momentum, and waveform, are obtained by applying differential operators, which are constructed from Dirac brackets and the generating functions, to the initial value of the observable. We demonstrate its power by calculating new high-precision results, including the impulse and spin kick for a probe in Kerr up to \(O(G^6 s^4)\), and the change in angular momentum for generic masses up to \(O(G^2 s^{11})\). Via analytic continuation, we can also provide information about bound orbits, such as their fundamental frequencies.
Posted by: Morteza S. Hosseini
Mon
15 Sep 2025
AI & the Future of Maths
📍 London
Yang-Hui He (LIMS)
Venue: LIMS · Room: Faraday Theatre · Time: 19:00 · Type: Colloquium
Abstract:
https://www.rigb.org/whats-on/mathematics-rise-machines

Royal Institution Public Lecture on AI & the future of Maths.
Posted by: Yang-Hui He
Mon
8 Sep 2025
South East Mathematical Seminar (SEMPS)
📍 South East
multiple speakers
Venue: SURREY · Time: 10:00 · Type: Exceptional Seminar
Abstract:
LMS funded one-day seminar series: Speakers: Omer Gurdogan, Simon Ekhammar, Ida Zadeh, Mehran Jalali Farahani, Nika Sokolova
Posted by: Alessandro Torrielli
Wed
3 Sep 2025
Spontaneous quantization of the Yang-Mills gradient flow
📍 London
Alexander Migdal (IAS Princeton)
Venue: LIMS · Room: LIMS, Royal Institution · Time: 14:00 · Type: Informal Seminar
Abstract:
We formulate a nonsingular loop-space calculus for the Yang-Mills (YM) gradient flow, in which all variations act within the manifold of smooth loops via ``dot derivatives'' that are finite, parametrization-invariant, and free of cusp or backtracking singularities. This yields an exact momentum-loop representation and a universal trilinear loop-space diffusion equation, valid for any non-Abelian gauge group. We identify two distinct classes of exact solutions. The first is a self-dual (Hodge-dual) matrix-valued minimal surface whose area functional, when exponentiated, solves the fixed-point loop equation exactly, without contact terms or ambiguities; for planar loops the dual area equals \(2\sqrt{2}\) times the Euclidean minimal area, providing a geometrically grounded confinement mechanism. We also prove that the ordinary minimal surface in ℝ4 fails to satisfy the fixed-point loop equation, due to a singular nonvanishing contribution from the loop operator. The second is a decaying-flow solution in which the momentum loop performs a periodic random walk on regular star polygons – the ``Euler ensemble'' previously found in Navier-Stokes turbulence – realizing a form of spontaneous quantization in the YM gradient flow. We discuss the emergence of quantum-like Wilson-loop statistics from deterministic classical dynamics, potential implications for confinement in QCD, and the role of these fixed points as attractors in the space of YM gradient-flow trajectories.
Posted by: Evgeny Sobko