Control of Quantum Echo and Bell State Swapping of Two Atomic Qubits in the Two-Mode Vacuum Field Environment
Abstract
We investigate quantum echo control and Bell state swapping for two atomic qubits (TAQs) coupling to two-mode vacuum cavity field (TMVCF) environment via two-photon resonance. We discuss the effect of initial entanglement factor 𝜃 and relative coupling strength R= g 1/ g 2 on quantum state fidelity of TAQs, and analyze the relation between three kinds of quantum entanglement( C( ρ a ), C( ρ f ), S( ρ a )) and quantum state fidelity, then reveal physical essence of quantum echo of TAQs. It is shown that in the identical coupling case R=1, periodic quantum echo of TAQs with π cycle is always produced, and the value of fidelity can be controlled by choosing appropriate 𝜃 and atom-filed interaction time. In the non-identical coupling case R≠1, quantum echoes with periods of π, 2 π and 4 π can be formed respectively by adjusting R. The characteristics of quantum echo results from the non-Markovianity of TMVCF environment, and then we propose Bell state swapping scheme between TAQs and two-mode cavity field.
- Publication:
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International Journal of Theoretical Physics
- Pub Date:
- November 2016
- DOI:
- 10.1007/s10773-016-3097-5
- Bibcode:
- 2016IJTP...55.4740L
- Keywords:
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- Periodic quantum echo;
- Bell state swapping;
- Non-Markovian environment