Quantum mean-field treatment of the dynamics of a two-level atom in a
simple cubic lattice
- URL: http://arxiv.org/abs/2206.14156v3
- Date: Thu, 6 Jul 2023 16:48:43 GMT
- Title: Quantum mean-field treatment of the dynamics of a two-level atom in a
simple cubic lattice
- Authors: Yamen Hamdouni
- Abstract summary: Entanglement sudden death and revival is shown to occur close to the critical temperature.
The dependence on the change of the temperature and the magnitude of spin is also investigated.
- Score: 0.0
- License: http://creativecommons.org/licenses/by/4.0/
- Abstract: The mean field approximation is used to investigate the general features of
the dynamics of a two-level atom in a ferromagnetic lattice close to the Curie
temperature. Various analytical and numerical results are obtained. We first
linearize the lattice Hamiltonian, and we derive the self-consistency equation
for the order parameter of the phase transition for arbitrary direction of the
magnetic field. The reduced dynamics is deduced by tracing out the degrees of
freedom of the lattice, which results in the reduction of the dynamics to that
of an atom in an effective spin bath whose size is equal to the size of a unit
cell of the lattice. It is found that the dephasing and the excited state
occupation probability may be enhanced by applying the magnetic field along
some specific directions. The dependence on the change of the temperature and
the magnitude of spin is also investigated. It turns out that the increase of
thermal fluctuations may reduce the occupation probability of the excited
state. The entanglement of two such atoms that occupy non-adjacent cells is
studied and its variation in time is found to be not much sensitive to the
direction of the magnetic field. Entanglement sudden death and revival is shown
to occur close to the critical temperature.
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