Probing many-body systems near spectral degeneracies

• URL: http://arxiv.org/abs/2108.13143v1
• Date: Mon, 30 Aug 2021 12:02:33 GMT
• Title: Probing many-body systems near spectral degeneracies
• Authors: Klaus Ziegler
• Abstract summary: diagonal elements of the time correlation matrix are used to probe closed quantum systems that are measured at random times. This separation is strongly affected when spectral degeneracies occur, for instance, in the presence of spontaneous symmetry breaking. Probing the quantum evolution with the diagonal elements of the time correlation matrix is discussed as a general concept and tested in the case of a bosonic Josephson junction.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: The diagonal elements of the time correlation matrix are used to probe closed quantum systems that are measured at random times. This enables us to extract two distinct parts of the quantum evolution, a recurrent part and an exponentially decaying part. This separation is strongly affected when spectral degeneracies occur, for instance, in the presence of spontaneous symmetry breaking. Moreover, the slowest decay rate is determined by the smallest energy level spacing, and this decay rate diverges at the spectral degeneracies. Probing the quantum evolution with the diagonal elements of the time correlation matrix is discussed as a general concept and tested in the case of a bosonic Josephson junction. It reveals for the latter characteristic properties at the transition to Hilbert-space localization.

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