Found at least 20 result(s)
regular seminar Ilya Pavlyukevich (Friedrich Schiller University Jena)
at: 01:00 - 01:00 KCL, Strand room: Strand Building S4.29 abstract: | We study solutions of the irregular Stratonovich SDE $dX = X|^\alpha \circ dB$, $\alpha\in (0, 1)$. In particular we construct solutions spending positive time in 0, describe solutions spending zero time in 0, and show how a particular physically natural solution can be singled out by means of an additional external "ambient" noise.
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regular seminar Sam Power (University of Bristol)
at: 01:00 - 01:00 KCL, Strand room: Strand Building S4.29 abstract: | The Random Walk Metropolis (RWM) is a simple and enduring Markov chain-based algorithm for approximate simulation from an intractable ‘target’ probability distribution. In this work, we study quantitatively the convergence of this algorithm, providing non-asymptotic estimates on mixing times, with explicit dependence on dimension and other problem parameters. The results hold at a reasonable level of generality, and are often sharp in a suitable sense.
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at: 01:00 - 01:00 KCL, Strand room: S4.23 abstract: | second lecture by Prof Leonid A. Pastur
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journal club Pardo Santos Diego (KCL)
at: 01:00 - 01:00 KCL, Strand room: Norfolk Building 342N abstract: | The non-minimal coupling of scalar fields to gravity has been claimed to violate energy conditions,
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regular seminar Shubham Gupta (Imperial College London)
at: 01:00 - 01:00 KCL, Strand room: S4.29 abstract: | In the Euclidean space setting, symmetrization inequalities is a classical theory that has been quite useful in solving problems coming from various parts of analysis: spectral geometry, variational problems, mathematical physics, spectral theory, to name a few. In my talk, I will discuss a possible extensions of this theory to the setting of graphs. It is a fairly new topic and most of the results in the area are proved in the last two years. I will talk about these developments, connections of this theory with discrete isoperimetric inequalities, and its possible applications to problems concerning 'analysis on graphs'. The talk will be at the interface of discrete math and analysis, and will be based on a joint work with Stefan Steinerberger. Keywords: |
Regular Seminar Marco Meineri (U. Turin)
at: 01:00 - 01:00 KCL Strand room: S0.12 abstract: | We consider the renormalization group flow of a quantum field theory (QFT) in Anti-de Sitter (AdS) space. We derive sum rules that express UV data and the energy of a chosen eigenstate in terms of the spectral densities and certain correlation functions of the theory. In two dimensions, this leads to a bootstrap setup that involves the UV central charge and may allow us to follow a Renormalization Group (RG) flow non-perturbatively by continuously varying the AdS radius. Along the way, we establish the convergence properties of the newly discovered local block decomposition, which applies to three-point functions involving one bulk and two boundary operators. Keywords: |
regular seminar Marco Meineri (U. Turin)
at: 01:00 - 01:00 KCL, Strand room: S0.12 abstract: | Keywords: |
regular seminar Sebastián Velazquez (King's College London)
at: 01:00 - 01:00 KCL, Strand room: S2.29 abstract: | We will review some general concepts of deformation theory. Then we will apply these ideas in order to explore the geometry of the moduli space Inv of foliations on a given variety $X$ around the points corresponding to foliations induced by Lie group actions. More precisely, let $X$ be a smooth projective variety over the complex numbers and $S(d)$ the scheme parametrizing $d$-dimensional Lie subalgebras of $H^0(X,\mathcal{T} X)$. For every $\mathfrak{g} \in S(d)$ one can consider the corresponding element $\mathcal{F}(\mathfrak{g})\in Inv$, whose generic leaf coincides with an orbit of the action of $\exp(\mathfrak{g})$ on $X$. We will show that under mild hypotheses, after taking a stratification $\coprod_i S(d)_i\to S(d)$ this assignment yields an isomorphism $\coprod_i S(d)_i\to Inv$ locally around $\mathfrak{g}$ and $\mathcal{F}(\mathfrak{g})$. Keywords: |
regular seminar Markus Riedle (King's College London)
at: 01:00 - 01:00 KCL, Strand room: Strand Building S4.29 abstract: | Cylindrical Lévy processes are a natural extension of cylindrical Brownian motion which has been the standard model of random perturbations of partial differential equations and other models in infinite dimensions for the last 50 years. Here, the attribute cylindrical refers to the fact that cylindrical Brownian motions are not classical stochastic processes attaining values in the underlying space but are generalised objects. The reasons for the choice of cylindrical but not classical Brownian motion can be found in the facts that there does not exist a classical Brownian motion with independent components in an infinite dimensional Hilbert space, and that cylindrical processes enable a very flexible modelling of random noise in time and space.
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journal club Pethybridge Ben ()
at: 01:00 - 01:00 KCL, Strand room: Norfolk Building 342N abstract: | Keywords: |
regular seminar Judith Rousseau (University of Oxford)
at: 01:00 - 01:00 KCL, Strand room: S5.20 abstract: | Multivariate nonlinear Hawkes processes are powerful models for multi-
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at: 01:00 - 01:00 KCL, Strand room: Nash Lecture Theatre K2.31 abstract: | The Disordered Systems Group at King's College London is organising a two-day event on the physics of disorder in both the classical and quantum setting, hosting a selection of international leading experts in the field. The first day of the event will be dedicated to our dear colleague Reimer Kühn, who is retiring at the end of the current academic year. The Workshop will be an opportunity to thank Reimer for his invaluable contributions to the field and to the life of our research group. More infos at https://disorderdayskcl.weebly.com/ Keywords: |
regular seminar Flavio Nicoletti (Sapienza University of Rome)
at: 01:00 - 01:00 KCL, Strand room: S3.31 abstract: | In recent years, great efforts have been devoted to the study of the vibrational spectrum of glasses [1]. Extensive numerical data show that the density of states of several different glassy models follows a quartic law at low frequencies, with related modes spatially quasi-localised. These observations are consistent with predictions of pre-existing phenomenological theories, like the soft potential model [2], in which a glass is effectively represented as a set of interacting anharmonic oscillators.
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regular seminar Stefan Geiss (University of Jyväskylä (Finland) )
at: 01:00 - 01:00 KCL, Strand room: abstract: | Assume a pure jump L\'evy process $X=(X_t)_{t\in [0,T]}$ with L\'evy measure $\nu$ and a Borel function $f:\rm{\bf R} \to \rm{\bf R}$ with $f(x+X_s)\in L_1$ for $(s,x)\in [0,T]\times \rm{\bf R}$. Define $F:[0,T]\times \rm{\bf R}\to \rm{\bf R}$ by
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Exceptional Seminar Sumit Das (Kentucky)
at: 01:00 - 01:00 KCL Strand room: K0.16 abstract: | Most realizations of holography in String Theory involve space-times of the form of AdS X Y, where Y is an internal space which geometrizes R symmetries. The initimate connection of bulk reconstruction in AdS with the entanglement of subregions of the base space of the dual field theory suggests the possibility that a reconstruction of the internal space could be related to entanglement among internal degrees of freedom. We initiate an investigation into this issue by studying properties of RT surfaces which are smeared along the AdS directions, and anchored on the boundary of a subregion of the internal space Y. In cases where the product space appears as an IR geometry of a higher dimensional asymptotically AdS space we identify the area of the RT surface with the entanglement entropy associated with an operator subalgebra, and speculate on stand alone instances of product spaces. Keywords: |
Exceptional Seminar Daniel Terno (Macquarie University)
at: 01:00 - 01:00 KCL Strand room: K6.63 abstract: | For a distant observer with finite lifetime the main characteristic a black hole is trapping of light. Semiclassical description of black holes and especially the logical basis for construction of exotic horizonless models are based on two common but usually implicit assumptions. The first is a consequence of the cosmic censorship conjecture, namely that curvature scalars are finite at
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Exceptional Seminar Jacques Distler (University of Texas Austin)
at: 01:00 - 01:00 KCL Strand room: K0.16 abstract: | 4D N=2 theories exhibit a rich structure of RG flows between UV and IR SCFTs. With G. Elliot, M.J. Kang and C. Lawrie, we have been this structure of RG flows from a variety of perspectives. In this talk, I would like to focus on the Vertex Operator Algebra (VOA) that can be associated to a 4D N=2 SCFT, and what these VOAs can tell us about the Higgs Branch RG flow between these theories. Keywords: |
regular seminar Ollie McGrath (King's College London)
at: 01:00 - 01:00 KCL, Strand room: S3.30 abstract: | In this talk we will see how sieve techniques can be used to count the number of solutions to certain Diophantine equations and in particular prove that polynomials have small "asymmetric additive energy." Keywords: |
Exceptional Seminar Aradhita Chattopadhyaya (Dublin Institute of Advanced Studies)
at: 01:00 - 01:00 KCL Strand room: K0.16 abstract: | We analyze the coefficients of partition functions of Vafa-Witten theory for the complex projective plane CP^2. We experimentally study the growth of the coefficients for gauge group SU(2) and SU(3), which are examples of mock modular forms of depth 1 and 2 respectively. We also introduce the notion of "mock cusp form'', and study an example of weight 3 related to the SU(3) partition function. Numerical experiments on the first 200 coefficients suggest that the coefficients of a mock modular form of weight k grow as the coefficients of a modular form of weight k, that is to say as n^{k-1}. On the other hand the coefficients of the mock cusp form appear to grow as n^{3/2}, which exceeds the growth of classical cusp forms of weight 3. We provide bounds using saddle point analysis, which however largely exceed the experimental observation. Keywords: |
regular seminar Dominik Bullach (King's College London)
at: 01:00 - 01:00 KCL, Strand room: K4.31 abstract: | Title: Dirichlet L-series at s = 0 and the scarcity of Euler systems
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