Triangle Seminars

Abstract:
The large-charge approach consists in studying conformal field theories in sectors of fixed and large global charge. This allows performing a perturbative expansion of a generically strongly-coupled theory with the inverse charge acting as a controlling parameter. In this talk, I will present the basic idea of the large-charge expansion using the simplest example of the 3D O(2) model at the Wilson-Fisher fixed point, as well as its application to other models.

Abstract:
Consider equations of motion yielding dispersion of an ensemble of particles. For
a given dynamical system an interesting problem is not only what type of diffusion
is generated but also whether the resulting diffusive dynamics matches to a known
stochastic process. I will discuss three examples of dynamical systems displaying
different types of diffusive transport: The first model is fully deterministic but nonchaotic
by showing a whole range of normal and anomalous diffusion under variation
of a single control parameter [1]. The second model is a soft Lorentz gas where a point
particles moves through repulsive Fermi potentials situated on a triangular periodic
lattice [2]. It is fully deterministic by displaying an intricate switching between
normal and superdiffusion under variation of control parameters. The third model
randomly mixes in time chaotic dynamics generating normal diffusive spreading with
non-chaotic motion where all particles localize [3]. Varying a control parameter the
mixed system exhibits a transition characterised by subdiffusion. In all three cases
I will show successes, failures and pitfalls if one tries to reproduce the resulting
diffusive dynamics by using simple stochastic models.

Joint work with all authors on the references cited below.

[1] L. Salari, L. Rondoni, C. Giberti, R. Klages, Chaos 25, 073113 (2015)
[2] R.Klages, S.S.Gallegos, J.Solanp¨a¨a, M.Sarvilahti, Phys. Rev. Lett. 122, 064102
(2019)
[3] Y.Sato, R.Klages, Phys. Rev. Lett. 122, 174101 (2019)

Abstract:
I will discuss a systematic way of taking into account non-perturbative effects on the closed string scattering amplitudes in c=1 string theory, and present a recent proposal on the corresponding non-perturbative completion of the dual matrix quantum mechanics.

Abstract:
I will discuss FZZT branes and long strings in c=1 string theory, and the dual description of the latter in non-singlet sectors of the matrix quantum mechanics. I will present highly nontrivial evidences for the duality at the level of perturbative scattering amplitudes, and discuss implications on black holes in c=1 string theory and their matrix model duals.

Abstract:
The Quantum Spectral Curve (QSC) is a powerful integrability-based framework capturing the exact spectrum of planar N=4 SYM. We present first evidence that it should also play an important role for computing exact correlation functions. We compute the correlator of 3 scalar local operators connected by Wilson lines forming a triangle in the ladders limit, and show that it massively simplifies when written in terms of the QSC. The final all-loop result takes a very compact form, suggesting its interpretation via Sklyanin's separation of variables (SoV). We discuss work in progress on extending these results to local operators. We also derive, for the first time, the SoV scalar product measure for gl(N) compact and noncompact spin chains.
Based on arXiv:1910.13442, 1907.03788, 1802.0423.