Searching for decoherence-free subspaces in cavity quantum electrodynamics

Abstract

We construct a model which describes a recently performed experiment (Phys. Rev. A 64, 050301(R) (2001)) in which an entangled state between two modes of a single cavity is built.Environmental effects are taken into account and the results agree with the experimental findings.Moreover the model predicts, for different conditions of the same experiment, a decoherence-free subspace. These conditions are analyzed and slightly different experiments suggested in order to test its viability.

Quantum Zeno effect in cavity quantum electrodynamics: Experimental proposal with nonideal cavities and detectors

“…Let us start by modeling the environment as a large set of harmonic oscillators linearly coupled to the system of interest (modes M A and M B ) [19]. This model has been used to calculate the time evolution of two microwave modes constructed in a single cavity, and the theoretical results showed good agreement with experimental ones [20]. In Ref.…”

Quantum state stability against decoherence

“…S. Bose et al [8] studied the enforcer of entanglement between a two-level system and a quantized mode in a thermal state. Decoherence-free subspaces in cavity QED have been found [9]. Also a method has been developed which achieves the slowing down of decoherence and relaxation by fast frequency modulation of the system-heat-bath coupling [10].…”

Two cavity modes in a dissipative environment: Cross decay rates and robust states

“…The experimental findings were compared to theoretical results in [8], with satisfactory agreement. However, due to the large detuning of the modes, the experiment is not sensitive to the cross decay rates: the parameters related to the their communication through the environment.…”

“…Some results related to them are population trapping [5,10] and decoherence free subspaces (DFS) [11,12]. The extension of the Caldeira-Legget model for two oscillators predicts the possibility of DFS if the cross decay rates are large enough [8]. Given the growing interest in DFS, the knowledge about this topic is accordingly important.…”

“…In the experiment with two cavities, we can maximize the effects of the parameter r by choosing the state built by the first atom; in this experiment with a single cavity, the first atom always constructs the state (8), and the effects of r will be maximized for γ = π/2 only. This is the condition that makes D more easy to detect, and it was used in Fig.…”