Interferometric measurements of the position of a macroscopic body: Towards observation of quantum limits

Abstract

An optomechanical sensor suitable for the study of quantum effects has been developed and characterized. The sensor reads out the vibrations of a microfabricated miniature silicon mechanical oscillator which forms one end mirror of a high finesse Fabry-Pérot cavity. The mechanical quality factor is up to Qϭ300 000 at 300 K and rises up to Qϭ4ϫ10 6 at 4 K. The thermal noise of the oscillator has been measured in the time and frequency domains at room temperature and at 4.5 K. The prospects for observing the standard quantum limit are discussed.

Phase-noise measurement in a cavity with a movable mirror undergoing quantum Brownian motion

“…of internal acoustic modes) thermal noise. Therefore it is very important to establish the experimental limitations determined by thermal noise and recent experiments [8,9] have obtained interesting results. With this respect it is also important to establish which is the most appropriate formal description of quantum Brownian motion.…”

Resolved-sideband cooling and position measurement of a micromechanical oscillator close to the Heisenberg uncertainty limit

“…It may provide insights into the quantum-classical boundary, experimental investigation of the theory of quantum measurements [1,3,4], the origin of mechanical decoherence [5] and generation of non-classical states of motion.…”

“…It may provide insights into the quantum-classical boundary, experimental investigation of the theory of quantum measurements [1,3,4], the origin of mechanical decoherence [5] and generation of non-classical states of motion.Prerequisite to this regime are both preparation of the mechanical oscillator at low phonon occupancy and a measurement sensitivity at the scale of the spread ∆x of the oscillator's ground state wavefunction. Over the past decade, it has been widely perceived that the most promising approach to address these two challenges are electro nanomechanical systems [2,6,7,8,9,10], which can be cooled with milli-Kelvin scale dilution refrigerators, and feature large ∆x ∼ 10 −14 m resolvable with electronic transducers such as a superconducting single-electron transistor [7,8,11], a microwave stripline cavity [9] or a quantum interference device [12].…”

“…The total optical loss through the cryogenic environment can reach values below 25%. Low pressure (0.1-50 mbar) Helium exchange gas is admitted into the sample chamber, thermalizing the sample with a heat exchanger through which 4 He is pumped from a reservoir of liquid 4 He. An exchange gas temperature of 1.65 K is achieved.…”

Cooling-by-measurement and mechanical state tomography via pulsed optomechanics

“…Such cavity-optomechanics experiments [4][5][6][7][8] have thus far largely concentrated on high sensitivity continuous monitoring of the mechanical position [9][10][11][12][13][14]. Because of the back-action imparted by the probe onto the measured object, the precision of such a measurement is fundamentally constrained by the standard quantum limit (SQL) [15,16], and therefore only allows for classical phase-space reconstruction [9,17,18]. In order to observe quantum mechanical features that are smaller than the mechanical zero-point motion, backaction-evading measurement techniques that can surpass the SQL [19,20] are required.…”