Production of entanglement in Raman three-level systems using feedback

Stevenson, Robin; Carvalho, André; Hope, Joseph

doi:10.1140/epjd/e2010-10442-2

Cited by 16 publications

(13 citation statements)

References 33 publications

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“…It turns out that Markovian quantum feedback can be used to increase the steady-state entanglement of the atoms [138][139][140][141][142][143][144][145][146][147][148][149][150][151]. It has been shown that this is possible using both feedback based on photon detections (quantum jumps) [145][146][147][148][149][150][151], and feedback using homodyne detection (trajectories driven by Gaussian noise) [138][139][140][141][142].…”

Section: Entanglement Creation and Controlmentioning

confidence: 99%

Quantum feedback: Theory, experiments, and applications

et al. 2017

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The control of individual quantum systems is now a reality in a variety of physical settings. Feedback control is an important class of control methods because of its ability to reduce the effects of noise. In this review we give an introductory overview of the various ways in which feedback may be implemented in quantum systems, the theoretical methods that are currently used to treat it, the experiments in which it has been demonstrated to-date, and its applications. In the last few years there has been rapid experimental progress in the ability to realize quantum measurement and control of mesoscopic systems. We expect that the next few years will see further rapid advances in the precision and sophistication of feedback control protocols realized in the laboratory.

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Section: Entanglement Creation and Controlmentioning

confidence: 99%

Quantum feedback: Theory, experiments, and applications

et al. 2017

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“…We enhance our scheme by combining the dissipative state preparation with the detection of photons. Improvement in state generation through conditional dynamics has been explored in schemes relying on feedback [20][21][22] and also used recently in [16]. Here we show that by conditioning the system dynamics to the detection of photons spontaneously emitted into the environment, we obtain a significant fidelity enhancement with detection efficiencies of 10%.…”

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confidence: 76%

Detection-Enhanced Steady State Entanglement with Ions

et al. 2014

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Driven dissipative steady state entanglement schemes take advantage of coupling to the environment to robustly prepare highly entangled states. We present a scheme for two trapped ions to generate a maximally entangled steady state with fidelity above 0.99, appropriate for use in quantum protocols. Furthermore, we extend the scheme by introducing detection of our dissipation process, significantly enhancing the fidelity. Our scheme is robust to anomalous heating and requires no sympathetic cooling.Decoherence is notorious for being a major obstacle to the development of quantum technologies that require sustained quantum coherence. Typically, the interaction of a quantum system with its surrounding environment drives the system towards states with no traces of quantum behaviour. However, it has long been recognised that this does not have to be the case: by combining the irreversible decoherence dynamics with suitably chosen Hamiltonian evolution, one can design artificial reservoirs to steer the system to the desired stationary states. This quantum reservoir engineering method [1] has been used to investigate decoherence [2,3] and to design robust non-classical states [4] in the motional degrees of freedom of trapped ions.More recently, the interest in designing dissipative processes has been renewed with proposals to engineer manybody quantum states [5,6] and even perform quantum computation [6]. Engineered reservoirs are robust to preexisting natural decoherence sources [4] and also to variations of parameters and initial conditions. This has led to a number of proposals to prepare and stabilise quantum steady-states in a variety of systems [7,8], including cavity quantum electrodynamics [9,10], optomechanical systems [11,12], and superconducting qubits [13]. Although experimentally challenging, engineered dissipation has been used to generate entanglement in atomic ensembles [14], to implement quantum operations in ion traps [15], and more recently to prepare Bell states in superconducting qubits [16] and in ion traps [17].Despite the intrinsic robustness of dissipative driven dynamics, the steady-state fidelities achieved in recent trapped ion experiments are far below the high fidelities achieved with more traditional time-dependent entangling gates [18] and, therefore, still much lower than the fidelities required for a quantum information processing (QIP) system [18,19]. In [15], for example, the entangling mechanism relies on successive applications of quantum gates to generate a quantum operation. Even though a fidelity of 0.91 has been achieved for a single cycle, fidelity decreases as the dynamics approach the continuous dissipative master equation limit. In contrast, Lin et al. [17] used continuous, time-independent fields and achieved fidelities of up to 0.75 that could be boosted to 0.89 using stepwise application of laser fields. In this case, the fidelity is limited by the intrinsic loss mechanisms present in the particular continuous driving scheme adopted.In this paper we propose a steady-stat...

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“…The difference is that

and

are the ground states and mode A is non-local. It should be noted that Stevenson et al have also derived a similar model with two Raman three-level systems in the same cavity [ 36 ], but we will see below that the coupled-cavity array system is much useful for stabilizing different Bell states. The dissipative dynamics of the whole system is characterized by the Markovian master equation

where the terms characterizing the spontaneous emission of atom has been neglected, since the atom is restricted in the subspace spanned by

.…”

Section: Effective Master Equation Of the Coupled-cavity Array Sysmentioning

confidence: 90%

Stabilization of All Bell States in a Lossy Coupled-Cavity Array

Shao

2019

Entropy

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A scheme is proposed to generate maximally entangled states of two Λ -type atoms trapped in separate overdamped optical cavities using quantum-jump-based feedback. This proposal can stabilize not only the singlet state, but also the other three triplet states by alternating the detuning parameter and relative phase of the classical fields. Meanwhile it is convenient to manipulate atoms, and much more robust against spontaneous emission of atoms. The parameters related to the potential experiment are analyzed comprehensively and it is confirmed that the quantum feedback technology is a significant tool for entanglement production with a high fidelity.

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Production of entanglement in Raman three-level systems using feedback

Cited by 16 publications

References 33 publications

Quantum feedback: Theory, experiments, and applications

Quantum feedback: Theory, experiments, and applications

Detection-Enhanced Steady State Entanglement with Ions

Stabilization of All Bell States in a Lossy Coupled-Cavity Array

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