Non-Markovianity and Coherence of a Moving Qubit inside a Leaky Cavity

Mortezapour, Ali; Borji, Mahdi Ahmadi; Park, DaeKil; Franco, Rosario Lo

doi:10.1142/s1230161217400066

Cited by 29 publications

(19 citation statements)

References 107 publications

(105 reference statements)

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“…(1), a † k (a k ) denotes the creation (annihilation) operator for the k-th cavity mode with frequency ω k and g k is the coupling constant between the qubit and the k-th mode. The parameter f k (z) describes the shape function of qubit motion along the z-axis, and it is given by [50][51][52] (2) where β = v/c, c being the speed of light. It is evident that the coupling function will be nonzero for z = 0 and zero for z = l (perfect boundary).…”

Section: Description Of the Modelmentioning

confidence: 99%

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Validating and controlling quantum enhancement against noise by the motion of a qubit

2020

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Experimental validation and control of quantum traits for an open quantum system are important for any quantum information purpose. We consider a traveling atom qubit as a quantum memory with adjustable velocity inside a leaky cavity, adopting a quantum witness as a figure of merit for quantumness assessment. We show that this model constitutes an inherent physical instance where the quantum witness does not work properly if not suitably optimized. We then supply the optimal intermediate blind measurements which make the quantum witness a faithful tester of quantum coherence. We thus find that larger velocities protect quantumness against noise, leading to lifetime extension of hybrid qubit-photon entanglement and to higher phase estimation precision. Control of qubit motion thus reveals itself as a quantum enhancer. arXiv:1911.07146v1 [quant-ph]

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Section: Description Of the Modelmentioning

confidence: 99%

“…The larger the cavity quality factor, the smaller the spectral width λ. We now recall for convenience the analytical calculation of the time-dependent coefficient A(t) [52]. In the continuum limit (τ → ∞) and t > t , analytic solution of Eq.…”

Section: Description Of the Modelmentioning

confidence: 99%

Validating and controlling quantum enhancement against noise by the motion of a qubit

2020

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“…In order to analyse the pairwise entanglement between qubit l and another generic qubit m, it is enough to set s = −1 in Eqs. (37) or (39). The dynamical behaviour of C l,m (τ ) is shown in Fig.…”

Section: B One Initial Excitationmentioning

confidence: 99%

Entanglement dynamics of moving qubits in a common environment

2020

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In this paper we provide an analytical investigation of the entanglement dynamics of moving qubits dissipating into a common and (in general) non-Markovian environment for both weak and strong coupling regimes. We first consider the case of two moving qubits in a common environment and then generalize it to an arbitrary number of moving qubits. We show that for an initially entangled state, the environment washes out the initial entanglement after a finite interval of time. We also show that the movement of the qubits can play a constructive role in protecting of the initial entanglement. In this case, we observe a Zeno-like effect due to the velocity of the qubits. On the other hand, by limiting the number of qubits initially in a superposition of single excitation, a stationary entanglement can be achieved between the qubits initially in the excited and ground states. Surprisingly, we illustrate that when the velocity of all qubits are the same, the stationary state of the qubits does not depend on this velocity as well as the environmental properties. This allows us to determine the stationary distribution of the entanglement versus the total number of qubits in the system.

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“…Since the genesis of many quantum phenomena traces back to coherence, nowadays this feature is considered as a key concept which enables tremendous possibilities in a wide spectrum of quantum technologies, quantum metrology [4][5][6][7], and quantum thermodynamics [8,9]. Several strategies have been then devised to protect coherence from being lost in quantum systems [7,[10][11][12][13][14][15][16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Quantum enhancement of qutrit dynamics through driving field and photonic band-gap crystal

Yousefi,

Mortezapour,

Naeimi

et al. 2022

Preprint

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A comparative study of a qutrit (three-level atomic system) coupled to a classical field in a typical Markovian reservoir (free space) and in a photonic band-gap (PBG) crystal is carried out. The aim of the study is to assess the collective impact of structured environment and classical control of the system on the dynamics of quantum coherence, non-Markovianity, and estimation of parameters which are initially encoded in the atomic state. We show that the constructive interplay of PBG material as a medium and classical driving field as a part of system results in a significant enhancement of all the quantum traits of interest, compared to the case when the driven qutrit is in a Markovian environment. Our results supply insights for preserving and enhancing quantum features in qutrit systems which are promising alternative candidates to be used in quantum processors instead of qubits.

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Non-Markovianity and Coherence of a Moving Qubit inside a Leaky Cavity

Cited by 29 publications

References 107 publications

Validating and controlling quantum enhancement against noise by the motion of a qubit

Validating and controlling quantum enhancement against noise by the motion of a qubit

Entanglement dynamics of moving qubits in a common environment

Quantum enhancement of qutrit dynamics through driving field and photonic band-gap crystal

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