Eur. Phys. J. D (2014) 68: 200
https://doi.org/10.1140/epjd/e2014-50140-5

Regular Article

Anomalous decoherence effects in driven coupled quantum spin systems

¹ College of Physics and Electronic Science, Hubei Normal University, Huangshi 435002, P.R. China
² Institute of Signal Processing and Transmission, Nanjing University of Posts and Telecommunication, Nanjing 210003, P.R. China

^a e-mail: chuanjiashan@hbnu.edu.cn

Received: 23 February 2014
Received in final form: 14 April 2014
Published online: 24 July 2014

Abstract

We discuss anomalous decoherence effects at zero and finite temperatures in driven coupled quantum spin systems. By numerical simulations of the quantum master equation, it is found that entanglement dynamics of two coupled spin qubits is qualitatively affected by the noise strength. The effects of noise strength, the detuning and finite temperature of independent boson reservoirs on the steady state entanglement are addressed in detail. Pumped by an external field drive, non-trivial steady states can be found, the steady state entanglement increases monotonically up to a maximum at certain optimal noise strength and decreases steadily for higher values. Furthermore, increasing the detuning can not only induce but also suppress steady state entanglement, which depends on the value of noise strength. At last, we delimit the border between presence or absence of steady state entanglement in the related finite temperatures.