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arXiv · 2107.10432

Ladder of Loschmidt anomalies in the deep strong-coupling regime of a qubit-oscillator system

J. M. Betancourt·F. J. Rodríguez·L. Quiroga·N. F. Johnson
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Abstract

We uncover a remarkably regular array of singularity-like structures within the deep strong-coupling limit of qubit-oscillator (e.g. light-matter) systems described by the quantum Rabi model, as a function of time and coupling strength. These non-analytic anomalies in the Loschmidt amplitude (echoes) suggest the existence of new forms of dynamical phase transition within this deep strong-coupling regime. The key feature whereby the initial state collapses into orthogonal states at select values of the interaction strength and select times, may be used to enhance - or attack - quantum information processing or computation schemes that rely on removing - or retaining - a given quantum state.

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J. M. Betancourt, F. J. Rodríguez, L. Quiroga, N. F. Johnson. 2021-07-22. Ladder of Loschmidt anomalies in the deep strong-coupling regime of a qubit-oscillator system. https://doi.org/10.1103/physreva.104.043712

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