Rapid mechanical squeezing with pulsed optomechanics

Abstract

Macroscopic mechanical oscillators can be prepared in quantum states and coherently manipulated using the optomechanical interaction. This has recently been used to prepare squeezed mechanical states. However, the scheme used in these experiments relies on slow, dissipative evolution that destroys the system's memory of its initial state. In this paper we propose a protocol based on a sequence of four pulsed optomechanical interactions. In addition to being coherent, our scheme executes in a time much shorter than a mechanical period. We analyse applications in impulsive force sensing and preservation of Schrödinger cat states, which are useful in continuous-variable quantum information protocols.

Stroboscopic quantum optomechanics

“…Over this time (i) the mechanical mode picks up a phase, which determines which quadrature is measured at the next interaction, and (ii) the mechanics exchanges phonons with the thermal environment. In particular, the presence of the latter contribution-neglected in previous studies [15][16][17][18][19]-competes with the measurement, eventually leading to a nonequilibrium steady state.…”

“…Pulsed protocols can also lift the stringent requirement of sideband resolution. By employing pulses much shorter than the mechanical period, quantum state preparation and readout, e.g., of low-entropy and squeezed mechanical states [14][15][16][17][18][19][20], as well as optomechanical and all-mechanical entanglement [21] can in principle be achieved. However, in order to neglect nonunitary processes, coherent operations are restricted to very short times (also less than a single mechanical cycle).…”

“…This however requires including mechanical dissipation in the description of the dynamics, as opposed to Refs. [15][16][17][18][19]. Due to the competition between radiationpressure interaction and mechanical dissipation, the mechanical system eventually settles into a steady state, albeit a periodic one.…”

Echoes of a squeezed oscillator

“…Although the term was originally introduced in quantum electrodynamics [2,3] and, more generally, to describe bosonic systems such as lattice modes [4,5], magnons [6] and localized vibrations [7,8,9], it has also been applied to spin states [10,11] as well as to ensembles of classical oscillators [12]. The reduction of noise below the thermal-or shot-noise limit is the main motivation for numerous proposals and experimental realizations of squeezing [1,2,4,6,7,10,12,13,14,15], including the use of squeezed light in the detection of gravitational waves [16].…”

Enhanced energy transfer to an optomechanical piston from indistinguishable photons

“…While considering an initial thermal state for the photon gases realises a close analogy with classical thermodynamics, including the process of pumping brings the discussion closer to an experimentally realizable situation. If the cavity is driven on resonance in a pulsed fashion [32][33][34][35], with pulses that are shorter than the tunnelling time λ, the driving processes and tunnelling processes occur on different time scales and can be considered independently. Accordingly, driving the left modes of the cavity with a short laser pulse of θ polarised photons and the right modes with a short pulse of vertically polarised photons, will generate the coherent states |α, θ and |α, V in the respective halves of the cavity [36], leading again to an enhanced energy transfer to the membrane for indistinguishable photons as per Eq.…”