1,720,967 research outputs found
Dissipative Engineering of Gaussian Entangled States in Harmonic Lattices with a Single-Site Squeezed Reservoir
No full textWe study the dissipative preparation of many-body entangled Gaussian states in bosonic lattice models which could be relevant for quantum technology applications. We assume minimal resources, represented by systems described by particle-conserving quadratic Hamiltonians, with a single localized squeezed reservoir.We show that in this way it is possible to prepare, in the steady state, the wide class of pure states which can be generated by applying a generic passive Gaussian transformation on a set of equally squeezed modes. This includes nontrivial multipartite entangled states such as cluster states suitable for measurement-based quantum computation
Possibility to generate any Gaussian cluster state by a multimode squeezing transformation
Full text linkGaussian cluster states are ideal infinitely squeezed states. In practice it is possible to construct only approximated version of them with finite squeezing. Here we show how to determine the specific multimode squeezing transformation, which generates a faithful approximation of any given Gaussian cluster state
Optomechanical Stirling heat engine driven by feedback-controlled light
Full text linkWe propose and analyze a microscopic Stirling heat engine based on an optomechanical system. The working fluid is a single vibrational mode of a mechanical resonator, which interacts by radiation pressure with a feedback-controlled optical cavity. The cavity light is used to engineer the thermal reservoirs and to steer the resonator through a thermodynamic cycle. In particular, the feedback is used to properly modulate the light fluctuations inside the cavity and hence to realize efficient thermodynamic transformations with realistic optomechanical devices
Optics-assisted enhanced sensing at radio frequencies in an optoelectromechanical system
Full text linkWe investigate a scheme to enhance the sensitivity in detecting weak variations in a parameter of an optoelectromechanical system by detecting the system response at radio frequencies. We consider a setup where either one or two mechanical modes mediate the interaction between an optical cavity and an rf resonator. This system can be operated in a regime of impedance matching where thermal fluctuations are redistributed among the system elements and, in particular, rf output noise can be reduced to the quantum vacuum noise level. We show that this effect can be used to boost the sensitivity in detecting parameter variations also in regimes of high thermal noise. We characterize the performance of this protocol in detecting variations in the capacitance of the rf resonator
Feedback-enabled Microwave Quantum Illumination
Full text linkA simple feedback scheme can be used to operate efficiently a
microwave-quantum-illumination device based on electro-optomechanical systems
also in regimes in which excess dissipation would, otherwise, prevent to
outperform the optimal classical illumination protocol with the same
transmitted energy
Nonreciprocal conversion between radio-frequency and optical photons with an optoelectromechanical system
Full text linkNonreciprocal systems breaking time-reversal symmetry are essential tools in
modern quantum technologies enabling the suppression of unwanted reflected
signals or extraneous noise entering through detection ports. Here we propose a
scheme enabling nonreciprocal conversion between optical and radio-frequency
(rf) photons using exclusively optomechanical and electromechanical
interactions. The nonreciprocal transmission is obtained by interference of two
dissipative pathways of transmission between the two electromagnetic modes
established through two distinct intermediate mechanical modes. In our
protocol, we apply a bichromatic drive to the cavity mode and a single-tone
drive to the rf resonator, and use the relative phase between the drive tones
to obtain nonreciprocity. We show that perfect nonreciprocal transduction can
be obtained in the limit of large cooperativity in both directions, from
optical to rf and vice versa. We also study the transducer noise and show that
mechanical thermal noise is always reflected back onto the isolated port. In
the limit of large cooperativity, the input noise is instead transmitted in an
unaltered way in the allowed direction; in particular one has only vacuum noise
in the output rf port in the case of optical-to-rf conversion
Dissipative stabilization of entangled qubit pairs in quantum arrays with a single localized dissipative channel
Full text linkWe study the dissipative stabilization of entangled states in arrays of
quantum systems. Specifically, we are interested in the states of qubits
(spin-1/2) which may or may not interact with one or more cavities (bosonic
modes). In all cases only one element, either a cavity or a qubit, is lossy and
irreversibly coupled to a reservoir. When the lossy element is a cavity, we
consider a squeezed reservoir and only interactions which conserve the number
of cavity excitations. Instead, when the lossy element is a qubit, pure decay
and a properly selected structure of XY-interactions are taken into account. We
show that in all cases, in the steady state, many pairs of distant,
non-directly interacting qubits, which cover the whole array, can get entangled
in a stationary way, by means of the interplay of dissipation and local
interactions
Enhancing strength and range of atom-atom interaction in a coupled-cavity array via parametric drives
No full textCoherent long-range interactions between atoms are a prerequisite for numerous applications in the field of quantum information science. Here we present an appealing method to dramatically enhance the long-range atom-atom interaction mediated by a coupled-cavity array that is subjected to two-photon (parametric) drives. Our method allows one to greatly amplify both the localization length of the single-photon bound-state wave function and the effective atom-photon coupling strength, resulting in a significant improvement of photon-mediated coherent interaction between two distant atoms. Additionally, we illustrate this effect by analyzing how it facilitates the transfer of information and the creation of entanglement between the atoms
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