Multipulse control of decoherence—nonlinear spin-boson model

Volker Bach, Alexander Hach

Marcus Motzkus

Chikako Uchiyama, Masaki Aihara

We present a general formulation to suppress pure dephasing by multipulse control. The formula is free from a specific form of interaction and is expressed in terms of the correlation function of an arbitrary system-reservoir interaction. We first apply the formula to a phenomenological two-level model where the correlation function of the interaction decays exponentially. In this case, we show analytically that the pure dephasing time is effectively lengthened by the multipulse control. Secondly, we apply the formula to the spin-boson model where a spin interacts nonlinearly with a boson reservoir. We find the multipulse control works well when the pulse interval is sufficiently shorter than the correlation time of the system-reservoir interaction. Moreover, in this case, the pure dephasing can also be suppressed by adjusting the pulse interval to the period of dynamical motion of the reservoir.

Chikako Uchiyama

Chikako Uchiyama, Masaki Aihara

We show that the multipulse application can suppress the degradation of the quantum entanglement with focusing on the concurrence, the degree of entanglement. By evaluating the time evolution of concurrence with a linearly interacting spin-boson model under pulse application, we find that the effectiveness of the multipulse control depends on the non-Markovian nature of the reservoir.

V. V. Dobrovitski