Unconditional Preparation of Entanglement between Atoms in Cascaded Optical Cavities

Clark, Stephen; Peng, Amy; Gu, Mile; Parkins, Scott

doi:10.1103/physrevlett.91.177901

Cited by 165 publications

(113 citation statements)

References 30 publications

(36 reference statements)

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“…This type of set-up is a part of environmental quantum-state engineering by dissipation, where one aims to drive the system into a desired steady state by using a carefully tailored environment. [25][26][27][28][29][30] Such engineering has already been used in generation of coherent superposition states, [31][32][33] in creation of entanglement, [34][35][36] and in simulations of open quantum systems. 37,38 In this paper, we focus on a ground-state initialization proposal, 39,40 where a superconducting qubit and a lowtemperature resistive bath are coupled indirectly through two resonators as shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

Efficient protocol for qubit initialization with a tunable environment

et al. 2017

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We propose an efficient qubit initialization protocol based on a dissipative environment that can be dynamically adjusted. Here, the qubit is coupled to a thermal bath through a tunable harmonic oscillator. On-demand initialization is achieved by sweeping the oscillator rapidly into resonance with the qubit. This resonant coupling with the engineered environment induces fast relaxation to the ground state of the system, and a consecutive rapid sweep back to off resonance guarantees weak excess dissipation during quantum computations. We solve the corresponding quantum dynamics using a Markovian master equation for the reduced density operator of the qubit-bath system. This allows us to optimize the parameters and the initialization protocol for the qubit. Our analytical calculations show that the ground-state occupation of our system is well protected during the fast sweeps of the environmental coupling and, consequently, we obtain an estimate for the duration of our protocol by solving the transition rates between the low-energy eigenstates with the Jacobian diagonalization method. Our results suggest that the current experimental state of the art for the initialization speed of superconducting qubits at a given fidelity can be considerably improved.

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Section: Introductionmentioning

confidence: 99%

Efficient protocol for qubit initialization with a tunable environment

et al. 2017

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“…In addition, there is a general lack of squeezed light sources coinciding with convenient atomic transitions [51]. It has been proposed that these difficulties could be circumvent by engineering a squeezed-reservoir-type interaction of a quantum system rather than coupling the system to a squeezed field produced by an external source [52,53]. For example, Lütkenhaus et al [54] have studied the dynamics of a four-level system driven by two laser fields and have shown that the system may effectively behave as a two-level system coupled to a squeezed reservoir.…”

Section: Introductionmentioning

confidence: 99%

Engineering a squeezed phonon reservoir with a bichromatic driving of a quantum dot

Gao

Ficek

2016

Phys. Rev. A

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We demonstrate how an acoustic phonon bath when coupled to a quantum dot with the help of a bichromatic laser field may effectively form a quantum squeezed reservoir. This approach allows one to achieve an arbitrary degree of squeezing of the effective reservoir and it incorporates the properties of the reservoir into two parameters, which can be controlled by varying the ratio of the Rabi frequencies of the bichromatic field. It is found that for unequal Rabi frequencies, the effective reservoir may appear as a quantum squeezed field of ordinary or inverted harmonic oscillators. When the Rabi frequencies are equal the effective reservoir appears as a perfectly squeezed field in which the decay of one of the polarization quadratures of the quantum dot dipole moment is inhibited. The decay of the quantum dot to a stationary state which depends on the initial coherence is predicted. This unusual result is shown to be a consequence of a quantum-nondemolition type coupling of the quantum dot to the engineered squeezed reservoir. The effect of the initial coherence on the steady-state dressed-state population distribution and the fluorescence spectrum is discussed in details. The complete polarization of the dressed state population and asymmetric spectra composed of only a single Rabi sideband peak are obtained under strictly resonant excitation.

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“…In the latter case the qubits are atoms and light is used exclusively as a connection bus between them [13,14,15,16,17,18,19]. Promising schemes to produce steady state entanglement between atoms in distinct cavities have also been proposed [19]. In these ground states of atoms have been used in order to circumvent decoherence due to spontaneous emission.…”

Section: Introductionmentioning

confidence: 99%

Steady-state entanglement between hybrid light-matter qubits

2009

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We study the case of two polaritonic qubits localized in two separate cavities coupled by a fiber/additional cavity. We show that surprisingly enough, even a coherent classical pump in the intermediate cavity/fiber can lead to the creation of entanglement between the two ends in the steady state. The stationary nature of this entanglement and its survival under dissipation opens possibilities for its production under realistic laboratory conditions. To facilitate the verification of the entanglement in an experiment we also construct the relevant entanglement witness measurable by accessing only a few local variables of each polaritonic qubit.

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Unconditional Preparation of Entanglement between Atoms in Cascaded Optical Cavities

Cited by 165 publications

References 30 publications

Efficient protocol for qubit initialization with a tunable environment

Efficient protocol for qubit initialization with a tunable environment

Engineering a squeezed phonon reservoir with a bichromatic driving of a quantum dot

Steady-state entanglement between hybrid light-matter qubits

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