Quantum Squeezing

Suhail Zubairy

Yanbo Lou, Shengshuai Liu, Jietai Jing

Abstract Quantum squeezing, which makes measurement sensitivity beyond classical limit by reducing system noise, is an essential non-classical resource for quantum metrology. It is of great importance to enhance quantum squeezing since the squeezing degree directly determines the extent to which measurement sensitivity beats the classical limit. Recently, a two-mode phase-sensitive amplifier has been utilized to enhance the quantum squeezing of phase-insensitive amplifier. However, such enhancement has an intrinsic limit of 3 dB. Here we show that such limit of 3 dB can be overcome by utilizing multi-beam interference. Specifically, a quantum squeezing enhancement of about 3.67 dB is observed by direct measurement. Moreover, we find that the amount of quantum squeezing enhancement increases as the number of multi-beam interference increases, which clearly shows that beating the quantum squeezing enhancement limit of 3 dB is induced by multi-beam interference. Our results here provide an efficient way to enhance the quantum squeezing.

Jian Ma, Xiaoguang Wang, C. P. Sun +1 more

Zhucheng Zhang, Yi‐Ping Wang, Ya‐Fei Yu +1 more

Quantum squeezing, as a typical quantum effect, is an important resource for many applications in quantum technologies. Here we propose a scheme for generating quantum squeezing, including the ponderomotive squeezing and the mechanical squeezing, in an optomechanical system, in which the radiation-pressure coupling and the mechanical spring constant are modulated periodically. In this system, the radiation-pressure interaction can be enhanced remarkably by the modulation-induced mechanical parametric amplification. Moreover, the effective phonon noise can be suppressed completely by introducing a squeezed vacuum reservoir. This ultimately leads to that our scheme can achieve a controllable quantum squeezing. Numerical calculations show that our scheme is experimentally realizable with current technologies.

Chuan Xu, Lidan Zhang, Songtao Huang +5 more

Quantum sensing, along with quantum communications and quantum computing, is commonly considered as the most important application of quantum optics. Among the quantum-sensing experiments, schemes based on squeezed states of light are popular choices due to their natural quadrature components. Since the first experimental demonstration of quantum-squeezing-enhanced phase measurement beyond the shot-noise limit in 1987, quantum-squeezing techniques toward practical sensing and tracking have been extensively investigated. In this paper, we briefly review the recent developments of quantum squeezing and its applications in several advanced systems for measurements of position, rotation, dynamic motion, magnetic fields, and gravitational waves. We also introduce the recent experimental efforts to combine the quantum-squeezing lights into fiber sensing systems.

Zi-Wei Jiang, Yan-Zi Jing, Zhen-Sen Lin +4 more

We investigate higher-order exceptional points and quantum squeezing of exciton polaritons in a pseudo-Hermitian semiconductor optomechanical system. We show that a third-order exceptional point (EP3) can emerge from the tripartite coupling among photons, excitons, and phonons under pseudo-Hermitian conditions. A pronounced two-mode quantum squeezing of exciton polaritons is revealed, and we demonstrate that this squeezing is significantly enhanced in the vicinity of the EP3. Furthermore, we find that in the PT-symmetric phase, the squeezing dynamics produce a frequency comb of exciton polaritons, whereas the squeezing remains constant over time in the PT-symmetry broken phase and exactly at the EP3. The sudden change in quantum squeezing dynamics can be used to probe the phase transition and the EP3. Our work opens a pathway to manipulate quantum squeezing in semiconductor optomechanical platforms, offering potential advantages for quantum sensing and metrology.