Environment-assisted quantum state restoration via weak measurements

Abstract

In this paper, a new quantum state restoration scheme is proposed based on the environmentassisted error correction (EAEC) scheme. By introducing a weak measurement reversal (WMR) operation, we shall show how to recover an initial state of a quantum open system without invoking random unitary decompositions which are known to be absent in many important physical systems. We illustrate our new scheme and compare it with a scheme purely based on the WMR operation in the case of dissipative channel. In the proposed new scheme, the successful probability of recovering an unknown initial state can be significantly improved when the information obtained from an environment measurement is taken into account. Moreover, we show that the applicable range of our proposed scheme is wider than the EAEC scheme. Finally, the optimization of the successful probability for possible Kraus decompositions is discussed.

Universal scheme for finite-probability perfect transfer of arbitrary multispin states through spin chains

“…In the context of open system dynamics, a number of controlling schemes have been developed to fight against the environmental noises (cf. [32] and references therein). Aiming at the suppression of decoherence of a single qubit in the amplitude damping channel, a scheme using prior weak measurement [33] followed by posterior quantum reversal measurement has been proposed [34] and experimentally demonstrated [35].…”

“…Unfortunately, the evolution of the spin chain in terms of the Kraus operators K 0 and K 1 does not satisfy this 'unitary random decomposition' condition. Nevertheless, still motivated by this idea [32,38], we develop an efficient strategy to restore the transferred state along the spin chains.…”

Enhanced Superdense Coding over Correlated Amplitude Damping Channel

“…In this paper, we focus on how to improve the capacity of superdense coding under CAD channel. With the help of two recent techniques named weak measurement (WM) [37][38][39][40][41][42] and environment-assisted measurement (EAM) [43][44][45] and combining with a appropriate quantum measurement reversal (QMR), we propose two probabilistic schemes called as WM+CAD+QMR and CAD+EAM+QMR, respectively, to further enhance the capacity over the CAD channel. Interestingly, the latter scheme is comprehensively superior to the former one in the improvements of capacity as well as successful probability.…”

Decoherence suppression of tripartite entanglement in non-Markovian environments by using weak measurements

“…In recent years, many applications via weak measurements for protecting entanglement from decoherence have been proposed [24][25][26][27][28][29][30][31][32]. For example, Kim et al [26] have proved that quantum weak measurements can actively resist decoherence experimentally.…”