The laws of thermodynamics require any initial macroscopic inhomogeneity in extended many-body systems to be smoothed out by the time evolution through the activation of transport processes. In generic quantum systems, transport is expected to be governed by a diffusion law, whereas a sufficiently strong quenched disorder can suppress it completely due to many-body localization of quantum excitations. Here, we show that the confinement of quasiparticles can also suppress transport even if the dynamics are generated by nondisordered Hamiltonians. We demonstrate this in the quantum Ising chain with transverse and longitudinal magnetic fields, prepared in a paradigmatic state with a domain wall and thus with a spatially varying energy density. We perform extensive numerical simulations of the dynamics which turn out to be in excellent agreement with an effective analytical description valid within both weak and strong confinement regimes. Our results show that the energy flow from ``hot'' to ``cold'' regions of the chain is suppressed for all accessible times. We argue that this phenomenon is general, as it relies solely on the emergence of confinement of excitations.

Suppression of transport in nondisordered quantum spin chains due to confined excitations / Mazza, Paolo Pietro; Perfetto, Gabriele; Lerose, Alessio; Collura, Mario; Gambassi, Andrea. - In: PHYSICAL REVIEW. B. - ISSN 2469-9950. - 99:18(2019), pp. 1-6. [10.1103/PhysRevB.99.180302]

Suppression of transport in nondisordered quantum spin chains due to confined excitations

Mazza, Paolo Pietro;Perfetto Gabriele;Lerose Alessio;Collura Mario;Gambassi Andrea
2019

Abstract

The laws of thermodynamics require any initial macroscopic inhomogeneity in extended many-body systems to be smoothed out by the time evolution through the activation of transport processes. In generic quantum systems, transport is expected to be governed by a diffusion law, whereas a sufficiently strong quenched disorder can suppress it completely due to many-body localization of quantum excitations. Here, we show that the confinement of quasiparticles can also suppress transport even if the dynamics are generated by nondisordered Hamiltonians. We demonstrate this in the quantum Ising chain with transverse and longitudinal magnetic fields, prepared in a paradigmatic state with a domain wall and thus with a spatially varying energy density. We perform extensive numerical simulations of the dynamics which turn out to be in excellent agreement with an effective analytical description valid within both weak and strong confinement regimes. Our results show that the energy flow from ``hot'' to ``cold'' regions of the chain is suppressed for all accessible times. We argue that this phenomenon is general, as it relies solely on the emergence of confinement of excitations.
99
18
1
6
180302
https://arxiv.org/abs/1806.09674
Mazza, Paolo Pietro; Perfetto, Gabriele; Lerose, Alessio; Collura, Mario; Gambassi, Andrea
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.11767/98111
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