3 research outputs found
Theory of bifurcation amplifiers utilizing the nonlinear dynamical response of an optically damped mechanical oscillator
We consider a standard optomechanical system where a mechanical oscillator is
coupled to a cavity mode through the radiation pressure interaction. The
oscillator is coherently driven at its resonance frequency, whereas the cavity
mode is driven below its resonance, providing optical damping of the mechanical
oscillations. We study the nonlinear coherent response of the mechanical
oscillator in this setup. For large mechanical amplitudes, we find that the
system can display dynamical multistability if the optomechanical cooperativity
exceeds a critical value. This analysis relates standard optomechanical damping
to the dynamical attractors known from the theory of optomechanical
self-sustained oscillations. We also investigate the effect of thermal and
quantum noise and estimate the noise-induced switching rate between the stable
states of the system. We then consider applications of this system and
primarily focus on how it can be used as bifurcation amplifiers for the
detection of small mechanical or optical signals. Finally, we show that in a
related but more complicated setup featuring resonant optomechanical
interactions, the same effects can be realized with a relaxed requirement on
the size of the mechanical oscillations.Comment: 20 pages, 12 figure
Scheme for steady-state preparation of a harmonic oscillator in the first excited state
We present a generic quantum master equation whose dissipative dynamics
autonomously stabilizes a harmonic oscillator in the n=1 Fock state. A
multi-mode optomechanical system is analyzed and shown to be an example of a
physical system obeying this model. We show that the optomechanical setup
enables preparation of a mechanical oscillator in a nonclassical steady state,
and that this state indeed approaches a single phonon Fock state in the ideal
parameter regime. The generic model may be useful in other settings, such as
cavity or circuit quantum electrodynamics or trapped ion physics.Comment: 4 pages, 3 figures + supplementary (7 pages, 2 figures) v2: Minor
changes, added a few reference
Detection of qubit-oscillator entanglement in nanoelectromechanical systems
Experiments over the past years have demonstrated that it is possible to
bring nanomechanical resonators and superconducting qubits close to the quantum
regime and to measure their properties with an accuracy close to the Heisenberg
uncertainty limit. Therefore, it is just a question of time before we will
routinely see true quantum effects in nanomechanical systems. One of the
hallmarks of quantum mechanics is the existence of entangled states. We propose
a realistic scenario making it possible to detect entanglement of a mechanical
resonator and a qubit in a nanoelectromechanical setup. The detection scheme
involves only standard current and noise measurements of an atomic point
contact coupled to an oscillator and a qubit. This setup could allow for the
first observation of entanglement between a continuous and a discrete quantum
system in the solid state.Comment: 9 pages, 3 figure