Entanglement purification through Zeno-like measurements

Yuasa, Kazuya; Nakazato, Hiromichi; Unoki, Makoto

doi:10.1080/09500340408233616

Cited by 3 publications

(13 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Since an entangled state of system A+B is one of the pure states, there is a possibility that we apply the purification mechanism described above to distill the initial (generally mixed) state of A+B to a desired entangled state. This possibility has already been pointed out and it has been explicitly demonstrated that one of the Bell states |Ψ − of the two qubit systems A+B can actually be extracted if we repeatedly measure one and the same state of another qubit system X, the interactions of which are symmetrical with respect to A and B, resulting with the maximal yield [5,6]. One of the limitations of this model is that the entanglement can be established only when the two systems A and B locally interact with the same system X at the same time and therefore it does not seem to allow to establish an entanglement between two systems that are spatially separated.…”

Section: Entanglement Distillation In a Two-qubit System A+b By mentioning

confidence: 92%

“…The eigenvalue λ n is complex valued in general, but its absolute value is bounded [5] 0 ≤ |λ n | ≤ 1. (2.8) This reflects the unitarity of the time evolution operator e −iHτ .…”

Section: Purification Via Repeated Measurementsmentioning

confidence: 99%

“…The particular form of interaction (3.3b) is shown to be suitable for this purpose following the procedure (3.2). In this section, another application of the purification mechanism [3,5,6] is explored in a system composed of a two-level system (e.g., an atom) interacting with two single-mode cavities. The two cavities may be located at spatially distant places (or may be near and separated later) and we aim at extracting an entanglement between the two-cavity states by repeatedly bringing the two-level atom into interaction with them and then selecting a particular state of the atom by measurements.…”

Section: Entanglement Distillation Of Cavity Modesmentioning

confidence: 99%

“…It is an elementary task to evaluate in this case the relevant evolution operator V c , analogously to (2.5), 5) and its explicit expression reads…”

Section: Entanglement Distillation Of Cavity Modesmentioning

confidence: 99%

“…Since an entangled state is one of the pure states of two quantum systems, say A and B, one can think of a possibility of extracting the entangled state between A and B by repeatedly performing measurements on X which interacts with both A and B. This possibility has already been pointed out [5,6] and explored to show that one of the Bell states can be extracted when this mechanism is applied to a three-qubit system, where qubits A and B always interact with the other qubit X on which one and the same measurement is repeatedly performed. Notice that in this case the two systems A and B are not spatially separated, because they are supposed to locally interact with X.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Distillation of entanglement between distant systems by repeated measurements on an entanglement mediator

et al. 2004

View full text Add to dashboard Cite

A recently proposed purification method, in which the Zeno-like measurements of a subsystem can bring about a distillation of another subsystem in interaction with the former, is utilized to yield entangled states between distant systems. It is shown that the measurements of a two-level system locally interacting with other two spatially separated not coupled subsystems, can distill entangled states from the latter irrespectively of the initial states of the two subsystems.

show abstract

Section: Entanglement Distillation In a Two-qubit System A+b By mentioning

confidence: 92%

“…The eigenvalue λ n is complex valued in general, but its absolute value is bounded [5] 0 ≤ |λ n | ≤ 1. (2.8) This reflects the unitarity of the time evolution operator e −iHτ .…”

Section: Purification Via Repeated Measurementsmentioning

confidence: 99%

Section: Entanglement Distillation Of Cavity Modesmentioning

confidence: 99%

“…It is an elementary task to evaluate in this case the relevant evolution operator V c , analogously to (2.5), 5) and its explicit expression reads…”

Section: Entanglement Distillation Of Cavity Modesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Distillation of entanglement between distant systems by repeated measurements on an entanglement mediator

et al. 2004

View full text Add to dashboard Cite

show abstract

Preparation of three- and four-qubit decoherence-free states via Zeno-like measurements

Shao¹,

Chen²,

Zhang³

et al. 2010

J. Phys. B: At. Mol. Opt. Phys.

View full text Add to dashboard Cite

Enlightened by the idea of purification through Zeno-like measurements (Nakazato et al 2003 Phys. Rev. Lett. 90 060401), we propose a scheme for generating three- and four-qubit decoherence-free states with respect to collective amplitude damping. The whole system is in a star configuration of a spin network and the outer spin qubits construct the decoherence-free state via measuring the state of central spin qubit at intervals of τ repeatedly. An interesting feature is found: namely, that in order to prepare the three-qubit decoherence-free state successfully, the value of τ for the projected time-evolution operator must be set definitely, while this restrictive condition is relaxed for achieving the four-qubit decoherence-free state. The simulation results reveal that the fidelity approaches one asymptotically, and the corresponding success probability reaches a stable value by increasing the number of measurements N.

show abstract

A Purification Scheme and Entanglement Distillations

Nakazato¹,

Unoki²,

Yuasa³

2006

Quantum Information and Computing

View full text Add to dashboard Cite

A purification scheme which utilizes the action of repeated measurements on a (part of a total) quantum system is briefly reviewed and is applied to a few simple systems to show how it enables us to extract an entangled state as a target pure state. The scheme is rather simple (e.g., we need not prepare a specific initial state) and is shown to have wide applicability and flexibility, and is able to accomplish both the maximal fidelity and non-vanishing yield.

show abstract

Entanglement purification through Zeno-like measurements

Abstract: We present a novel method for purifying quantum states, i.e. purification through Zeno-like measurements, and show an application to entanglement purijication. = 14)x (41 8 Q~' ( N ) , (2) Journal of Modern Optics

Cited by 3 publications

References 4 publications

Distillation of entanglement between distant systems by repeated measurements on an entanglement mediator

Distillation of entanglement between distant systems by repeated measurements on an entanglement mediator

Preparation of three- and four-qubit decoherence-free states via Zeno-like measurements

A Purification Scheme and Entanglement Distillations

Contact Info

Product

Resources

About