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We report an efficient mechanism to generate mechanical entanglement in a two-cascaded cavity optomechanical system with optical parametric amplifiers (OPAs) inside the two coupled cavities. We use the especially tuned OPAs to squeeze the hybrid mode composed of two mechanical modes, leading to strong macroscopic entanglement between the two movable mirrors. The squeezing parameter as well as the effective mechanical damping are both modulated by the OPA gains. The optimal degree of mechanical entanglement therefore depends on the balanced process between coherent hybrid mode squeezing and dissipation engineering. The mechanical entanglement is robust to strong cavity decay, going beyond simply resolved sideband regime, and is resistant to reasonable high thermal noise. The scheme provides an alternative way for generating strong macroscopic entanglement in cascaded optomechanical systems.
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http://dx.doi.org/10.1364/OE.379058 | DOI Listing |
Int J Womens Health
August 2025
Key Laboratory of Evidence Science (China University of Political Science and Law), Ministry of Education, Beijing, 100088, People's Republic of China.
Background: Umbilical cord hemorrhage (UCH) is a rare but catastrophic obstetric emergency associated with nearly 50% fetal mortality, and its precise pathogenic mechanisms remain elusive in clinical practice. The pathophysiological cascade involves hemorrhagic expansion from ruptured umbilical vessels predominantly the umbilical vein which generates compressive forces on adjacent umbilical arteries within the constrained Wharton's jelly. This acute vascular compromise precipitates the sudden cessation of fetoplacental circulation, culminating in irreversible hypoxic-ischemic injury.
View Article and Find Full Text PDFJ Chem Theory Comput
September 2025
Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States.
Molecular polaritons are hybrid light-matter states that enable the exploration of potential cavity-modified chemistry. The development of dynamical, first-principles approaches for simulating molecular polaritons is important for understanding their origins and properties. Herein, we present a hierarchy of first-principles methods to simulate the real-time dynamics of molecular polaritons in the strong coupling regime.
View Article and Find Full Text PDFWe propose a scheme for generating genuinely tripartite entanglements in microcavity exciton polaritons comprised of an exciton, photon, and phonon modes. We search for robust stationary bipartite and tripartite entanglements by optimizing optomechanical parameters while revealing the mechanism for generating entangled states by non-Hermitian spectrum. Maximum photon-phonon and exciton-phonon bipartite entanglements appear at the cross points of real eigenvalues in the non-Hermitian spectrum, while photon-exciton bipartite entanglements and tripartite entanglements are related to the breaking of parity-time symmetry.
View Article and Find Full Text PDFJ Phys Chem Lett
July 2025
Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States.
Producing and maintaining molecular entanglement at room temperature and detecting multipartite entanglement features of macroscopic molecular systems remain key challenges for understanding intermolecular quantum effects in chemistry. Here, we study the quantum Fisher information, as a multipartite entanglement witness. We generalize the entanglement witness functional related to quantum Fisher information regarding nonidentical local response operators.
View Article and Find Full Text PDFPhys Rev Lett
June 2025
Universität Innsbruck, Institut für Theoretische Physik, Technikerstraße 21a, A-6020 Innsbruck, Austria.
Because of the inherently probabilistic nature of quantum mechanics, each experimental realization of a dynamical quantum system can produce distinct measurement outcomes, particularly when coupled to a dissipative environment. Although quantum trajectories that lead to exotic, highly entangled states are possible in principle, their observation is typically hindered by extremely low probabilities. In this Letter, we present a method to significantly enhance the probability of generating highly entangled states in an ensemble of atoms undergoing collective superradiant decay on timescales much shorter than the individual atomic spontaneous emission rate.
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