Transport in the sine-Gordon field theory: from generalized hydrodynamics to semiclassics
ID Bertini, Bruno (Author), ID Piroli, Lorenzo (Author), ID Kormos, Márton (Author)

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The semiclassical approach introduced by Sachdev and collaborators proved to be extremely successful in the study of quantum quenches in massive field theories, both in homogeneous and inhomogeneous settings. While conceptually very simple, this method allows one to obtain analytic predictions for several observables when the density of excitations produced by the quench is small. At the same time, a novel generalized hydrodynamic (GHD) approach, which captures exactly many asymptotic features of the integrable dynamics, has recently been introduced. Interestingly, also this theory has a natural interpretation in terms of semiclassical particles and it is then natural to compare the two approaches. This is the objective of this work: we carry out a systematic comparison between the two methods in the prototypical example of the sine-Gordon field theory. In particular, we study the “bipartitioning protocol” where the two halves of a system initially prepared at different temperatures are joined together and then left to evolve unitarily with the same Hamiltonian. We identify two different limits in which the semiclassical predictions are analytically recovered from GHD: a particular nonrelativistic limit and the low-temperature regime. Interestingly, the transport of topological charge becomes subballistic in these cases. Away from these limits we find that the semiclassical predictions are only approximate and, in contrast to the latter, the transport is always ballistic. This statement seems to hold true even for the so-called “hybrid” semiclassical approach, where finite time DMRG simulations are used to describe the evolution in the internal space.

Keywords:statistical physics
Typology:1.01 - Original Scientific Article
Organization:FMF - Faculty of Mathematics and Physics
Publication status:Published
Publication version:Author Accepted Manuscript
Number of pages:Str. 035108-1-035108-25
Numbering:Vol. 100, iss. 3
PID:20.500.12556/RUL-113038 This link opens in a new window
ISSN on article:2469-9950
DOI:10.1103/PhysRevB.100.035108 This link opens in a new window
COBISS.SI-ID:3389540 This link opens in a new window
Publication date in RUL:29.11.2019
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Record is a part of a journal

Title:Physical review
Publisher:American Physical Society
COBISS.SI-ID:2997348 This link opens in a new window

Secondary language

Keywords:statistična fizika


Funder:EC - European Commission
Funding programme:H2020
Project number:694544
Name:Open many-body non-equilibrium systems

Funder:ARRS - Slovenian Research Agency
Project number:P1-0402
Name:Matematična fizika

Funder:ARRS - Slovenian Research Agency
Project number:N1-0055
Name:Termalizacija v neravnovesnih kvantnih sistemih

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