Joint generation of identical squeezed states

Graham P. Greve, Kevin C. Cox, Baochen Wu +1 more

Paula B. Monteiro, Adriano Aragão, Ardiley Torres Avelar +1 more

Thomas Gerrits, Martin J. Stevens, Burm Baek +13 more

We characterize a periodically poled KTP crystal that produces an entangled, two-mode, squeezed state with orthogonal polarizations, nearly identical, factorizable frequency modes, and few photons in unwanted frequency modes. We focus the pump beam to create a nearly circular joint spectral probability distribution between the two modes. After disentangling the two modes, we observe Hong-Ou-Mandel interference with a raw (background corrected) visibility of 86% (95%) when an 8.6 nm bandwidth spectral filter is applied. We measure second order photon correlations of the entangled and disentangled squeezed states with both superconducting nanowire single-photon detectors and photon-number-resolving transition-edge sensors. Both methods agree and verify that the detected modes contain the desired photon number distributions.

Chen-Rui Yang, Huan-Huan Cheng, Shao‐Xiong Wu +1 more

We propose a proposal to achieve strong mechanical squeezing in an optomechanical system through the joint effect of a weak squeezed vacuum field and Duffing nonlinearity. The squeezing of the cavity field induced by the squeezed vacuum field is transferred to the mechanical oscillator, which has already been squeezed via Duffing nonlinearity. This joint effect significantly enhances the degree of mechanical squeezing, enabling it to exceed the 3 dB strong mechanical squeezing limit. Moreover, the resulting mechanical squeezing exhibits remarkable robustness against thermal noise. The joint effect proposed in this scheme can be directly observed through homodyne detection of the cavity output field. This novel approach opens up a new avenue for generating a strong mechanical squeezed state and provides a promising pathway for the applications of macroscopic quantum control in quantum sensing and quantum information processing.

Gunnar G. Bjork, Olle Nilsson, Y. Yamamoto +1 more

M.‐A. Dupertuis, Alexey N. Kireev

Multiatom quasi-intelligent and squeezed states with more than two atoms are constructed. A new general criterion for the squeezing of quasi-intelligent states and a method adapted to find maximally squeezed states are proposed. Multiatom quasi-intelligent states related to the collective dipole moment of an arbitrary number of non-identical two-level atoms are constructed. Squeezed states of the system of identical two-level atoms are investigated on the basis of symmetric multiatom states. The authors show in particular that there are no stationary squeezed states for which the expectation value of the collective dipole rising and lowering operators vanish for an odd number of atoms, whilst arbitrary large squeezing is realisable with an even number of atoms. A constructive procedure to generate squeezed light from the ground state by a squeezed multiatom system is proposed. These properties do not depend on whether the multiatom system consists of identical or non-identical atoms.