Purification and redistribution of entanglement via single local filtering

Abstract

The effect of filtering operation with respect to purification and concentration of entanglement in quantum states are discussed in this paper. It is shown, through examples, that the local action of the filtering operator on a part of the composite quantum state allows for purification of the remaining part of the state. The redistribution of entanglement in the subsystems of a noise affected state is shown to be due to the action of local filtering on the non-decohering part of the system. The varying effects of the filtering parameter, on the entanglement transfer between the subsystems, depending on the choice of the initial quantum state is illustrated.

Maximizing the encoded information via freezing the estimated parameters of a pulsed driven qubit

“…In Figs. (7) and ( 8), we investigate the behavior of the Fisher information F φ and the encoded information when the phase parameter (φ) is estimated, such that the driven qubit is initially prepared in the state e −iφ 1 , namely, we set the weight parameter θ = π. It is clear that, the larger values of the detuning has a decoherence effect on the Fisher information,F φ , where it decreases as ∆ increases.…”

“…There are different techniques that have been introduced to protect these states' decoherence. Among of these methods are quantum purification [5], weak measurement [6], and quantum filtering [7].…”

Enhancing entanglement, local and non-local information of accelerated two-qubit and two-qutrit systems via weak-reverse measurements

“…where B 1 = 1 4 (1+c 33 ), B 2 = 1 4 (c 11 +c 22 ), B 3 = 1 4 (1−c 33 ), and B 4 = 1 4 (c 11 −c 22 ), and c i , i = 1, 2, 3 are the diagonal elements of 3 × 3 cross dyadic. The state (7) can be described by its Bloch vectors, → s j = 0, j = 1, 2 and a dyadic ↓ −→ C with c ij = 0 for i = j. From this state, one can get maximum entangled classes, MES.…”

“…The possibility of purifying and concentrating entanglement by using local filtering is discussed by Yashodamma et. al, [7]. The immunity and protecting the entanglement of accelerated qubit-qutrit system by using the local filtering technique is investigated by Metwally [8].…”

Immunity, Improving and Retrieving the lost entanglement of accelerated qubit-qutrit system via local Filtering

“…A single local filter operation can be used to retrieve the loss of entanglement of particles passing through noise channels [9]. Moreover local filtering is used to increase the entanglement of subsystem at the expense of the other subsystem [10]. The effect of local filtering on the dynamics of some measures of quantum correlation of a general two qubit state is discusses by Karmakar et.…”