Spectral Evidence of Squeezing of a Weakly Damped Driven Nanomechanical Mode

Year: 2020

Authors: Huber J.S., Rastelli G., Seitner M.J., Ktzlbl J., Belzig W., Dykman M.I., Weig E.M.

Autors Affiliation: Univ Konstanz, Dept Phys, D-78457 Constance, Germany; Michigan State Univ, E Lansing, MI 48824 USA; Univ Basel, Dept Phys, CH-4056 Basel, Switzerland

Abstract: Because of the broken time-translation symmetry, in periodically driven vibrational systems fluctuations of different vibration components have different intensities. Fluctuations of one of the components are often squeezed, whereas fluctuations of the other component, which is shifted in phase by ?/2, are increased. Squeezing is a multifaceted phenomenon; it attracts much attention from the perspective of high-precision measurements. Here we demonstrate a new and hitherto unappreciated side of squeezing: its direct manifestation in the spectra of driven vibrational systems. With a weakly damped nanomechanical resonator, we study the spectrum of thermal fluctuations of a resonantly driven nonlinear mode. In the attained sideband-resolved regime, we show that the asymmetry of the spectrum directly characterizes the squeezing. This opens a way to deduce squeezing of thermal fluctuations in strongly underdamped resonators, for which a direct determination by a standard homodyne measurement is impeded by frequency fluctuations. The experimental and theoretical results are in excellent agreement. We further extend the theory to also describe the spectral manifestation of squeezing of quantum fluctuations.

Journal/Review: PHYSICAL REVIEW X

Volume: 10 (2)      Pages from: 021066  to:

More Information: Financial support by the Deutsche Forschungsgemeinschaft via the collaborative research center SFB 767, the European Union´s Horizon 2020 Research and Innovation Programme under Grant Agreement No. 732894 (FET Proactive HOT), and the German Federal Ministry of Education and Research (Contract No. 13N14777) within the European QuantERA co-fund project QuaSeRT is gratefully acknowledged. M. I. D. also acknowledges support from the Zukunftskolleg Senior Fellowship at the University of Konstanz and from the National Science Foundation (Grant No. DMR-1806473).
KeyWords: Squeezing; PARAMETRIC AMPLIFICATION; NOISE; STATES; SYSTEMS
DOI: 10.1103/PhysRevX.10.021066