Measurement of Motion beyond the Quantum Limit by Transient Amplification

Author
Abstract
Through simultaneous but unequal electromechanical amplification and cooling processes, we create a method for a nearly noiseless pulsed measurement of mechanical motion. We use transient electromechanical amplification (TEA) to monitor a single motional quadrature with a total added noise -8.5 ± 2.0 dB relative to the zero-point motion of the oscillator, or equivalently the quantum limit for simultaneous measurement of both mechanical quadratures. We demonstrate that TEA can be used to resolve fine structure in the phase space of a mechanical oscillator by tomographically reconstructing the density matrix of a squeezed state of motion. Without any inference or subtraction of noise, we directly observe a squeezed variance 2.8 ± 0.3 dB below the oscillator's zero-point motion.
Year of Publication
2019
Journal
Physical Review Letters
Volume
123
Number of Pages
183603
Date Published
2019-10
ISSN Number
0031-9007
URL
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.123.183603
DOI
10.1103/PhysRevLett.123.183603
JILA PI
Associated Institutes
Journal Article