1,721,005 research outputs found
Reservoir engineering of a mechanical resonator: generating a macroscopic superposition state and monitoring its decoherence
Full text linkA deterministic scheme for generating a macroscopic superposition state of a nanomechanical resonator is proposed. The nonclassical state is generated through a suitably engineered dissipative dynamics exploiting the optomechanical quadratic interaction with a bichromatically driven optical cavity mode. The resulting driven dissipative dynamics can be employed for monitoring and testing the decoherence processes affecting the nanomechanical
resonator under controlled conditions
Quantum phase gate for optical qubit with cavity quantum optomechanics
Full text linkWe show that a cavity optomechanical system formed by a mechanical resonator simultaneously coupled to two modes of an optical cavity can be used for the implementation of a deterministic quantum phase gate between optical qubits associated with the two intracavity modes. The
scheme is realizable for sufficiently strong single-photon optomechanical coupling in the resolved sideband regime, and is robust against cavity losses
Feedback control of two-mode output entanglement and steering in cavity optomechanics
Full text linkWe show that the closed-loop control obtained by feeding back the derivative of the signal from the homodyne measurement of one mode of the light exiting a two-mode optical cavity interacting with a mechanical resonator permits us to control and increase optical output entanglement. In particular, the proposed feedback-enhanced setup allows us to achieve a fidelity of coherent-state teleportation greater than the threshold value of 2/3 for secure teleportation and two-way steering between the two cavities’ output modes down the line in the presence of loss, which otherwise would not be possible without feedback
Suppression of Stokes scattering and improved optomechanical cooling with squeezed light
Full text linkWe develop a theory of optomechanical cooling with a squeezed input light field. We show that Stokes heating transitions can be fully suppressed when the driving field is squeezed below the vacuum noise level at an appropriately selected squeezing phase and for a finite amount of squeezing. The quantum backaction limit to laser cooling can be thereforemoved down to zero and the resulting final temperature is then solely determined by the ratio between the thermal phonon number and the optomechanical cooperativity parameter, independently of the actual values of the cavity linewidth and mechanical frequency. Therefore, driving with a squeezed input field allows us to prepare nanomechanical resonators, even with low resonance frequency, in their quantum ground state with a fidelity very close to one,
Mechanical Einstein-Podolsky-Rosen entanglement with a finite-bandwidth squeezed reservoir
Full text linkWe describe a scheme for entangling mechanical resonators which is efficient beyond the resolved sideband regime. It employs the radiation pressure force of the squeezed light produced by a degenerate optical parametric oscillator, which acts as a reservoir of quantum correlations (squeezed reservoir), and it is effective when the spectral bandwidth of the reservoir and the field frequencies are appropriately selected. It allows for the steady state preparation of mechanical resonators in entangled Einstein-Podolsky-Rosen states and can be extended to the preparation of many entangled pairs of resonators which interact with the same light field, in a situation in which the optomechanical system realizes a starlike harmonic network
Large distance continuous variable communication with concatenated swaps
Full text linkThe radiation–pressure interaction between electromagnetic fields and mechanical resonators can be used to efficiently entangle two light fields coupled to the same mechanical mode. We analyze the performance of this process under realistic conditions, and we determine the effectiveness of the resulting entanglement as a resource for quantum teleportation of continuous-variable light signals over large distances, mediated by concatenated swap operations. We study the sensitiveness of the protocol to the quality factor of the mechanical systems, and its performance in non-ideal situations in which losses and reduced detection efficiencies are taken into account
High-fidelity ground state cooling of a mechanical resonator via squeezed light driving
No full textWe show that preparation of nonclassical states of a mechanical resonator with close-to-one fidelity is possible by driving a cavity optomechanical system with squeezed vacuum light
Enhancing the Entanglement by Negative Feedback
Full text linkUsing a negative feedback in the cold damping approach it will be shown that it is possible to increase the entanglement between two optical modes exiting from a Fabry-Perot cavity with an oscillating end mirror
Robust stationary mechanical squeezing in a kicked quadratic optomechanical system
Full text linkWe propose a scheme for the generation of a robust stationary squeezed state of a mechanical resonator in a quadratically coupled optomechanical system, driven by a pulsed laser. The intracavity photon number presents periodic intense peaks suddenly stiffening the effective harmonic potential felt by the mechanical resonator. These “optical spring kicks” tend to squeeze the resonator position, and due to the interplay with fluctuation-dissipation processes one can generate a stationary state with more than 10 dB of squeezing in a realistic scenario, even starting from moderately “precooled” initial thermal states
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