Non-equilibrium critical scaling and universality in a quantum simulator

• URL: http://arxiv.org/abs/2309.10856v1
• Date: Tue, 19 Sep 2023 18:04:25 GMT
• Title: Non-equilibrium critical scaling and universality in a quantum simulator
• Authors: A. De, P. Cook, K. Collins, W. Morong, D. Paz, P. Titum, G. Pagano, A. V. Gorshkov, M. Maghrebi, C. Monroe
• Abstract summary: Universality and scaling laws are hallmarks of equilibrium phase transitions and critical phenomena. We show that the amplitude and timescale of the post-quench fluctuations scale with system size with distinct universal critical exponents. Our results demonstrate the ability of quantum simulators to explore universal scaling beyond the equilibrium paradigm.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: Universality and scaling laws are hallmarks of equilibrium phase transitions and critical phenomena. However, extending these concepts to non-equilibrium systems is an outstanding challenge. Despite recent progress in the study of dynamical phases, the universality classes and scaling laws for non-equilibrium phenomena are far less understood than those in equilibrium. In this work, using a trapped-ion quantum simulator with single-ion resolution, we investigate the non-equilibrium nature of critical fluctuations following a quantum quench to the critical point. We probe the scaling of spin fluctuations after a series of quenches to the critical Hamiltonian of a long-range Ising model. With systems of up to 50 spins, we show that the amplitude and timescale of the post-quench fluctuations scale with system size with distinct universal critical exponents. While a generic quench can lead to thermal critical behaviour, we find that a second quench from one critical state to another (i.e. a double quench) results in critical behaviour that does not have an equilibrium counterpart. Our results demonstrate the ability of quantum simulators to explore universal scaling beyond the equilibrium paradigm.

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