Schrödinger cats escape confinement

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Schrödinger cats escape confinement
2024. 03. 01. 10:15
BME building F, seminar room of the Dept. of Theoretical Physics
Anna Krasznai (BME)
In this talk, I discuss 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[1]. Contrary to global quenches, where the light-cone behaviour is strongly suppressed, after local quenches a significant light-cone signal propagating with a nonzero velocity emerges 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 Schrödinger cats of left and right-moving mesons escaping confinement. In contrast, for anti-confining quenches built upon the false vacuum, it is composed of Schrödinger cats of left and right-moving bubbles which escape Wannier-Stark localisation. 
[1] A. Krasznai, G. Takács, arXiv:2401.04193