Freiburg 2024 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 16: Bosonic Quantum Gases III (joint session Q/A)
Q 16.5: Talk
Tuesday, March 12, 2024, 12:00–12:15, Aula
Emergence of fluctuating hydrodynamics in chaotic quantum systems — •Julian Wienand1,2,3, Simon Karch1,2,3, Alexander Impertro1,2,3, Christian Schweizer1,2,3, Ewan McCulloch4, Romain Vasseur4, Sarang Gopalakrishnan5, Monika Aidelsburger1,2,3, and Immanuel Bloch1,2,3 — 1Fakultät für Physik, Ludwig-Maximilians-Universität, 80799 Munich, Germany — 2Max-Planck-Institut für Quantenoptik, 85748 Garching, Germany — 3Munich Center for Quantum Science and Technology (MCQST), 80799 Munich, Germany — 4Department of Physics, University of Massachusetts, Amherst, MA 01003, USA — 5Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ 08544, USA
A fundamental principle of chaotic quantum dynamics is that local subsystems eventually approach a thermal equilibrium state. Large subsystems thermalise slower: their approach to equilibrium is limited by the hydrodynamic build-up of fluctuations on extended length scales. We perform large-scale quantum simulations that monitor particle-number fluctuations in tunable ladders of hard-core bosons and explore how the build-up of fluctuations changes as the system crosses over from ballistic to chaotic dynamics. Our results indicate that the growth of large-scale fluctuations in chaotic far-from-equilibrium systems is even quantitatively determined by equilibrium transport coefficients, in agreement with the predictions of fluctuating hydrodynamics. This emergent hydrodynamic behaviour of fluctuations provides a novel test of fluctuation-dissipation relations far from equilibrium.
Keywords: chaos; fluctuations; correlations; crossover; diffusion