Decoherence and Loschmidt echo for qubit induced by a reservoir of coupled bosons

Shraddha Sharma, Victor Mukherjee, A. Dutta

Zhongjie Wang, Qijia Tai

Henrik Johannesson, Rouhollah Jafari

Zhongjie Wang, Xu Fang, Ren-Gui Zhu

The Loschmidt echo of single qubit coupling to the environment for dimerized anisotropic XY spin chain in transverse field have been analyzed.We have obtained analytical expression for the Loschmidt echo.By numerically computing the Loschmidt echo, we find that the decay of coherence will be enhanced with the increasing of the staggered parameter.

Yong-Cheng Ou, Heng Fan

For a central system uniformly coupled to a XY spin-1/2 bath in a transverse field, we explicitly calculate the Loschmidt echo(LE) to characterize decoherence quantitatively. We find that the anisotropy parameter $γ$ affects decoherence of the central system sensitively when $γ\in [0,1]$% , in particular, the LE becomes unit without varying with time when $γ=0 $, implying that environment-induced decoherence vanishes . Some other cases in which the LE is unit are discussed also.

Sahel Ashhab, J. R. Johansson, Franco Nori