Escaping fronts in local quenches of a confining spin chain

Autor: Anna Krasznai, Gábor Takács
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: SciPost Physics, Vol 16, Iss 5, p 138 (2024)
Druh dokumentu: article
ISSN: 2542-4653
DOI: 10.21468/SciPostPhys.16.5.138
Popis: We consider local quenches from initial states generated by a single spin-flip in either the true or the false vacuum state of the confining quantum Ising spin chain in the ferromagnetic regime. Contrary to global quenches, where the light-cone behaviour is strongly suppressed, we find a significant light-cone signal propagating with a nonzero velocity besides the expected localised oscillating component. Combining an analytic representation of the initial state with a numerical description of the relevant excitations using the two-fermion approximation, we can construct the spectrum of post-quench excitations and their overlaps with the initial state, identifying the underlying mechanism. For confining quenches built upon the true vacuum, the propagating signal consists of superpositions of left and right-moving mesons escaping confinement. In contrast, for anti-confining quenches built upon the false vacuum it is composed of superpositions of left and right-moving bubbles which escape Wannier-Stark localisation.
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