Multipulse control of decoherence

Abstract

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 arbitrary system-reservoir interaction. We first apply the formula to a phenomenological twolevel model where the correlation function of the interaction decays exponentially. In this case, we analytically show 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 nonlinearly interacts with a boson reservoir. We find the multipulse control works well when the pulse interval is sufficiently shorter than the correlation time of 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 reservoir.

Optimal control of quantum gates and suppression of decoherence in a system of interacting two-level particles

“…Therefore, it is very important to decrease the errors caused by decoherence. This problem has inspired significant interest in various methods of decoherence management, including the use of decoherence-free subspaces and noiseless subsystems [8,9,10,11,12], quantum dynamical decoupling [13,14,15,16,17,18,19,20], schemes based on stochastic control [21], optimal control techniques [22,23,24,25,26,27], and multilevel encoding of logical states [28].…”

Generation and Suppression of Decoherence in Artificial Environment for Qubit System

“…Firstly, we show that decoherence can be generated by manipulating the artificial environment. Secondly, we verify by NMR experiments that decoherence control methods, such as a bang-bang control, 7,8 actually suppress decoherence. It should be noted that demonstration of the effectiveness of decoherence control methods is rather difficult in other systems due to their extremely short coherence times.…”

“…Several groups 7,8 have proposed and analyzed a useful technique to suppress decoherence, which is called a quantum bang-bang control. We briefly explain the principle of the bang-bang control.…”

Soft-pulse dynamical decoupling with Markovian decoherence

“…Dynamical decoupling [1,2,3] (DD) can be very effective in protecting coherence of a quantum system against low-frequency environment [4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25]. This, combined with low resource requirement, makes it attractive as the first-level coherence protection technique, in combination with quantum error correcting codes [26,27] (QECC).…”