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March 2023
Viktor Eisler: Entanglement spreading across a defect
The study of quantum quenches had a vast contribution to our understanding of out-of-equilibrium dynamics and relaxation in closed many-body systems. The investigation of entanglement growth in a quench could shed light to various features of the underlying physics, in particular for integrable systems. However, most of the studies focus on setups where the system is driven far from equilibrium due to the inhomogeneity of the initial state. In my talk, I will present results for quenches where the time evolution operator is made…
Find out more »Pieter Claeys: Exactly-solvable many-body quantum dynamics in biunitary circuits
In recent years dual-unitary circuits have emerged as minimal models for chaotic quantum many-body systems in which the dynamics of correlations and entanglement remains tractable. The building blocks of these circuits are gates that are unitary in both time and space. After an introduction to these circuits I will extend the notion of dual-unitarity to biunitarity, which allows for a richer variety of building blocks and circuit dynamics, as well as unifying different notions of 'dual-unitarity'. The resulting interactions are…
Find out more »April 2023
Giuseppe Policastro: Matrix Quantum Mechanics and quantum averaging of JT gravity
I will discuss the matrix quantum mechanics with potential corresponding to an arbitrary spectral curve. This can be seen as a generalization of the duality between JT gravity and a particular matrix integral. Using the recently developed techniques of quantum generalised hydrodynamics, the effective theory of the eigenvalue density fluctuations is a simple 2D free-boson BCFT on a curved background. The ensemble average over random matrices then corresponds to a quantum expectation value. Using this formalism we reproduce non-perturbative results…
Find out more »Oleg Lisovyi: Semiclassical approach to form factors in the sinh-Gordon model
I will discuss a semiclassical approach to form factors in the sinh-Gordon field theory in the background of a radial classical solution that describes a heavy exponential operator placed at the origin. I will introduce and study new special functions which generalize the Bessel functions and have a nice interpretation in the Tracy–Widom theory of the Fredholm determinant solutions of the classical sinh-Gordon model. Unusual venue: F1 room, 1st floor
Find out more »Shane Kelly: Coherence and Scrambling in Quantum Circuits Coupled to a Monitored Environment
I will present our recent work on information transitions induced by coupling to an environmental. The first transition I will discuss occurs in a monitored random circuit where previously it was shown that a competition between unitaries and measurements can generate an entanglement transition. Instead here, we will show that an entanglement transition can instead be tuned by a competition between coherence generating and coherence destroying circuit elements. The second transition I will present occurs in a circuit that exchanges…
Find out more »May 2023
Kevin Kavanagh: Topological fingerprints in Liouvillian gaps
In quantum physics, topological properties usually emerge as a feature of equilibrium quantum states. We show that topological fingerprints can also manifest in the relaxation rates of open quantum systems. To demonstrate this we consider one of the simplest models that has two distinct topological phases in its ground state: the Kitaev model for the p-wave superconductor. After introducing dissipation to this model we estimate the Liouvillian gap in both strong and weak dissipative regimes. Our results show that a…
Find out more »Wilke van der Schee: A dynamical inflaton coupled to strongly interacting matter
In talk I will show how to self-consistently couple the Einstein-inflaton equations to a strongly coupled quantum field theory (QFT) as described by holography. We show that this can lead to an inflating universe, a reheating phase and finally a universe dominated by the QFT in thermal equilibrium. Special attention will be given to technical details that could be of relevance for modelling of more general holographic set-ups that for instance include charge.
Find out more »Scientific symposium in memory of Marko Medenjak (1990-2022)
On 12th and 13th 2023 will be held the symposium on Nonequilibrium many-body dynamics in memory of our colleague and friend Marko Medenjak who passed away last year. All talks will be given in the F1 room on the ground floor of the Faculty of Physics building, Jadranska 19. The symposium is open to all interested. Please find the program here.
Find out more »Marcello Porta: Edge transport in interacting quantum Hall systems
The bulk-edge correspondence is a remarkable duality in condensed matter physics, relating the value of bulk topological invariants to the emergence of gapless edge modes. In the case of the integer quantum Hall effect, the value of the Hall conductivity is equal to the sum of signed edge modes, taking into account their chirality. For noninteracting systems, this fact is by now understood in full mathematical rigor. For interacting models, in the last years there has been progress in the…
Find out more »July 2023
Nitin Gupta: Quantum Chaos and Quantum Phase Transitions
Quantum Complexity has emerged in the past few years as a candidate for quantum chaos diagnostic. This talk is based on a work that appeared last year, in which we show that a notion of quantum complexity (spread complexity / Krylov state complexity) is sensitive to Topological Phase Transitions - at least for the prototypical Kitaev chain. I'll give a brief overview of what we mean when we say "quantum” chaos, make connections with classical chaos and proceed to discuss…
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