We study the post-quench unitary dynamics of a quantum sunburst spin model, composed of a transverse-field quantum Ising ring which is suddenly coupled to a set of independent external qubits along the longitudinal direction, in a way to respect a residual translation invariance and the Ising Z_2 symmetry. Starting from the different equilibrium quantum phases of the system, we characterize the decoherence and the energy storage in the external qubits, which may be interpreted as a probing apparatus for the inner Ising ring. Our results show that, in proximity of the quantum transitions of the Ising ring, either first-order or continuous, it is possible to put forward dynamic finite-size scaling frameworks which unveil peculiar scaling regimes, depending on the way in which the large-size limit is taken: either by fixing the number n of probing qubits, or their interspace distance b. In any case, the dependence of the various observables on n can be reabsorbed into a redefinition of the quench parameter by a \sqrt{n} prefactor. We also address the role of a nearest-neighbor coupling between the external qubits.

Decoherence and energy flow in the sunburst quantum Ising model

Alessio Franchi;Davide Rossini;Ettore Vicari
2022-01-01

Abstract

We study the post-quench unitary dynamics of a quantum sunburst spin model, composed of a transverse-field quantum Ising ring which is suddenly coupled to a set of independent external qubits along the longitudinal direction, in a way to respect a residual translation invariance and the Ising Z_2 symmetry. Starting from the different equilibrium quantum phases of the system, we characterize the decoherence and the energy storage in the external qubits, which may be interpreted as a probing apparatus for the inner Ising ring. Our results show that, in proximity of the quantum transitions of the Ising ring, either first-order or continuous, it is possible to put forward dynamic finite-size scaling frameworks which unveil peculiar scaling regimes, depending on the way in which the large-size limit is taken: either by fixing the number n of probing qubits, or their interspace distance b. In any case, the dependence of the various observables on n can be reabsorbed into a redefinition of the quench parameter by a \sqrt{n} prefactor. We also address the role of a nearest-neighbor coupling between the external qubits.
2022
Franchi, Alessio; Rossini, Davide; Vicari, Ettore
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/1164715
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