2009/09/17 by P. Pérez-Fernández, P. Perez-Fernandez, A. Relano +5 · 3 citations
Computer Science · Physics and Astronomy · #Boson #Excited state #Phase transition #Physics #Quantum #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum critical point #Quantum decoherence #Quantum dissipation #Quantum electrodynamics #Quantum mechanics #Quantum phase transition #Qubit #Spectroscopy and Quantum Chemical Studies #Statistical physics #nucl-th #quant-ph
paper · pdf · doi:10.1103/physreva.80.032111
published as Phys.Rev.A80:032111,2009
openalex publication_date 2009/09/17 · arxiv created 2010/01/03 · arxiv updated 2015/05/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The decoherence induced on a single qubit by its interaction with the environment is studied. The environment is modeled as a scalar two-level boson system that can go through either first-order or continuous-excited-state quantum phase transitions, depending on the values of the control parameters. A mean-field method based on the Tamm-Damkoff approximation is worked out in order to understand the observed behavior of the decoherence. Only the continuous-excited-state phase transition produces a noticeable effect in the decoherence of the qubit. This is maximal when the system-environment coupling brings the environment to the critical point for the continuous phase transition. In this situation, the decoherence factor (or the fidelity) goes to zero with a finite-size scaling power law.