Achieving the Ground State and Enhancing Optomechanical Entanglement

Jindao Tang, Qizhi Cai, Ze-Di Cheng +9 more

Haixing Miao, S. L. Danilishin, H. Müller‐Ebhardt +1 more

For cavity-assisted optomechanical cooling experiments, in order to achieve the quantum ground state of the mechanical oscillator, the cavity bandwidth needs to be smaller than the mechanical frequency. In the literature, this is the so-called resolved-sideband or good-cavity limit, and this is based on an understanding of optomechanical dynamics. We provide a different but physically equivalent explanation of such a limit: that is, information loss due to finite cavity bandwidth. With an optimal feedback control to recover the information in the cavity output, we can surpass the resolved-sideband limit and achieve the quantum ground state. In addition, recovering this information can also significantly enhance the entanglement between the cavity mode and the mechanical oscillator. Especially when the environmental temperature is high, such optomechanical entanglement will either exist or vanish critically depending on whether information is recovered or not. This provides a vivid example of a quantum eraser in the optomechanical system.

Zeng‐Xing Liu, Xiao-Jie Zuo, Jia-Xin Peng +1 more

Quantum sensing, leveraging the principles of quantum mechanics, has revolutionized the field of precision measurement by achieving sensitivities beyond the classical limits. Among the various platforms for quantum sensing, cavity optomechanics has emerged as a particularly promising field. It studies the interaction between light and mechanical resonators within high-Q optical cavities, providing unique opportunities for enhancing measurement precision and sensitivity in quantum sensing. With advancements in technology, the range of applications for cavity optomechanics in quantum sensing is expanding rapidly. Particularly, the integration of optoelectronic technologies and miniaturization techniques holds promise for the development of more compact, efficient, and scalable quantum sensors. Quantum sensing with cavity optomechanics has been extensively studied and has progressed enormously over the past decades. This paper provides a systematic review of research on quantum sensing with cavity optomechanics, starting from the fundamental principles of optomechanical coupling, to the achievement of quantum ground-state cooling of mechanical oscillators and the preparation of basic quantum states, and then to the mechanisms of quantum sensing based on cavity optomechanics. Furthermore, we survey recent advancements in quantum sensing utilizing cavity optomechanics, including the enhancement of optomechanical sensing through the use of entanglement, squeezing, and quantum exceptional points. Finally, perspectives and opportunities for future developments of this field are provided.

E. Kongkui Berinyuy, Carolle Tchodimou, Philippe Djorwé +3 more

Guoyao Li, Zhang‐qi Yin

Abstract Limited by the thermal environment, the entanglement of a massive object is extremely difficult to generate. Based on a coherent scattering mechanism, we propose a scheme to generate the entanglement of two optically levitated nanospheres through the Coulomb interaction. Two nanospheres are charged and coupled to each other through the Coulomb interaction. In this manner, the entanglement of two nanospheres is induced either under a weak/strong optomechanical coupling regime or under an ultra-strong optomechanical coupling regime. The charges, radius and distance of the two nanospheres are taken into consideration to enhance the Coulomb interaction, thereby achieving a higher degree of entanglement in the absence of ground-state cooling. The corresponding maximum entanglement can be attained as the dynamics of the system approaches the boundary between the steady and the unsteady regimes. This provides a useful resource for both quantum-enhanced sensing and quantum information processing, as well as a new platform for studying many-body physics.

Amjad Sohail, Mishal Rana, Sana Ikram +4 more