Enhanced force sensitivity based on Duffing nonlinearity in a dissipatively coupled optomechanical system.

The study of force sensitivity based on a cavity optomechanical system plays a prominent role in quantum precision measurement and provides an ideal platform for precision sensing technology. Here, we propose a scheme to enhance the force sensitivity of a dissipatively coupled optomechanical system by inducing Duffing nonlinearity. The numerical analysis shows that inducing Duffing nonlinearity significantly improves the force sensitivity compared to the system without Duffing nonlinearity, even surpassing the standard quantum limit (SQL) by more than five orders of magnitude.

Manipulating one-way quantum steering in a mechanical gain-loss optomechanical system.

Based on the phenomenon of exceptional points (EPs) in the optomechanically induced mechanical -symmetric binary and ternary systems, we propose a mechanism to generate the perfect one-way quantum steering between two totally symmetric modes, respectively. By investigating the quantum steering behavior in the close vicinity of EP, we find that the optimal one-way quantum steering can be successfully generated at the EP in the -symmetric binary mechanical system. When pushing the system towards the EP, we show that not only is the broadest region of the one-way quantum steering achieved, but the robustness against the thermal noise can be significantly enhanced.

Enhancement of optomechanical cooling via synthetic magnetism and frequency modulation.

We propose a scheme to enhance optomechanical cooling via synthetic magnetism and frequency modulation (FM) in a three-mode loop-coupled optomechanical system. By introducing synthetic magnetism, the dark-mode effect can be broken, ensuring the simultaneous cooling of the two mechanical resonators. We find that the cooling of the two mechanical resonators is destroyed in the dark-mode-unbreaking (DMU) regime but can be achieved in the dark-mode-breaking (DMB) regime.

Topological phases and non-Hermitian topology in tunable nonreciprocal cyclic three-mode optical systems.

We propose a method for simulating a 1D non-Hermitian Su-Schrieffer-Heeger model with modulated nonreciprocal hopping using a cyclic three-mode optical system. The current system exhibits different localization of topologically nontrivial phases, which can be characterized by the winding number. We find that the eigenenergies of such a system undergo a real-complex transition as the nonreciprocal hopping changes, accompanied by a non-Bloch parity-time symmetry breaking.

Nonreciprocal -symmetric magnon laser in spinning cavity optomagnonics.

We propose a scheme to achieve nonreciprocal parity-time ( )-symmetric magnon laser in a -symmetric cavity optomagnonical system. The system consists of active and passive optical spinning resonators. We demonstrate that the Fizeau light-dragging effect induced by the spinning of a resonator results in significant variations in magnon gain and stimulated emitted magnon numbers for different driving directions.

Parametrically amplified nonreciprocal magnon laser in a hybrid cavity optomagnonical system.

We propose a scheme to achieve a tunable nonreciprocal magnon laser with parametric amplification in a hybrid cavity optomagnonical system, which consists a yttrium iron garnet (YIG) sphere and a spinning resonator. We demonstrate the control of magnon laser can be enhanced via parametric amplification, which make easier and more convenient to control the magnon laser. Moreover, we analyze and evaluate the effects of pump light input direction and amplification amplitude on the magnon gain and laser threshold power.

Squeezing-induced nonreciprocal photon blockade in an optomechanical microresonator.

We propose a scheme to generate nonreciprocal photon blockade in a stationary whispering gallery microresonator system based on two physical mechanisms. One of the two mechanisms is inspired by recent work [Phys. Rev.

Conventional photon blockade in the dispersive limit for Tavis-Cummings model.

In the dispersive limit, the conventional photon blockade effect cannot be realized due to the absence of photon nonlinearity. We propose a scheme to recover the photon blockade effect of the dispersive Tavis-Cummings model, which makes it possible to realize the conventional photon blockade effect in the dispersive limit. It is shown that both single-photon and two-photon blockade effects can be recovered at appropriate qubit driving strength.

Nonreciprocal photon blockade in a spinning optomechanical system with nonreciprocal coupling.

A scheme is presented to achieve quantum nonreciprocity by manipulating the statistical properties of the photons in a composite device consisting of a double-cavity optomechanical system with a spinning resonator and nonreciprocal coupling. It can be found that the photon blockade can emerge when the spinning device is driven from one side but not from the other side with the same driving amplitude. Under the weak driving limit, to achieve the perfect nonreciprocal photon blockade, two sets of optimal nonreciprocal coupling strengths are analytically obtained under different optical detunings based on the destructive quantum interference between different paths, which are in good agreement with the results obtained from numerical simulations.

Quantum entanglement and one-way steering in a cavity magnomechanical system via a squeezed vacuum field.

We propose a simple scheme to generate quantum entanglement and one-way steering between distinct mode pairs in a generic cavity magnomechanical system, which is composed of a microwave cavity and a yttrium iron garnet sphere supporting magnon and phonon modes. The microwave cavity is pumped by a weak squeezed vacuum field, which plays an important role for establishing quantum entanglement and steering. It is found that when the magnon mode is driven by the red-detuned laser, the maximum entanglement between cavity mode and phonon mode and the maximum phonon-to-photon one-way steering can be effectively generated via adjusting the ratio of two coupling rates.

Observing two-particle Anderson localization in linear disordered photonic lattices.

We theoretically and systematically investigate Anderson localization of two bosons with nearest-neighbor interaction in one dimension under short- and long-time scales, two types of disorders, and three types of initial states, which can be directly observed in linear disordered photonic lattices via two experimentally measurable physical quantities, participation ratio and spatial correlation. We find that the behavior of localization characterized by the participation ratio depends on the strength of interaction and the type of disorder and initial condition. Two-boson spatial correlation reveals more novel and unique features.

Generation and transfer of squeezed states in a cavity magnomechanical system by two-tone microwave fields.

We propose a scheme to generate squeezed states of magnon and phonon modes and verify squeezing transfer between different modes of distinct frequencies in a cavity magnomechanical system which is composed of a microwave cavity and a yttrium iron garnet sphere. We present that by activating the magnetostrictive force in the ferrimagnet, realized by driving the magnon mode with red-detuned and blue-detuned microwave fields, the driven magnon mode can be prepared in a squeezed state. Moreover, the squeezing can be transferred to the cavity mode via the cavity-magnon beamsplitter interaction with strong magnomechanical coupling.

Localized photonic states and dynamic process in nonreciprocal coupled Su-Schrieffer-Heeger chain.

We investigate the localized photonic states and dynamic process in one-dimensional nonreciprocal coupled Su-Schrieffer-Heeger chain. Through numerical calculation of energy eigenvalue spectrum and state distributions of the system, we find that different localized photonic states with special energy eigenvalues can be induced by the nonreciprocal coupling, such as zero-energy edge states, interface states and bound states with pure imaginary energy eigenvalues. Moreover, we analyze the dynamic process of photonic states in such non-Hermitian system.

Dissipative bosonic squeezing via frequency modulation and its application in optomechanics.

The dissipative squeezing mechanism is an effective method to generate the strong squeezing, which is important in the precision metrology. Here, we propose a practical method to achieve arbitrary bosonic squeezing via introducing frequency modulation into the coupled harmonic resonator model. We analyze the effect of frequency modulation and give the analytical and numerical squeezing results, respectively.

Quantum walks in periodically kicked circuit QED lattice.

We investigate the quantum walks of a single particle in a one-dimensional periodically kicked circuit quantum electrodynamics lattice. It is found that the dynamic process of the quantum walker is affected by the strength of incommensurate potentials and the driven periods of the system. We calculate the mean square displacement to illustrate the dynamic properties of the quantum walks, which shows that the localized process of the quantum walker presents the zero power-law index distribution.

Enhanced photon blockade in an optomechanical system with parametric amplification.

We propose a scheme to enhance the single- and two-photon blockade effects significantly in a nonlinear hybrid optomechanical system with optical parametric amplification (OPA). The scheme does not rely on strong single-photon optomechanical coupling and can eliminate the disadvantages of suppressing multi-photon excitation incompletely. Through analyzing the single-photon blockade (1PB) mechanism and optimizing the system parameters, we obtain a perfect 1PB with a high occupancy probability of single-photon excitation, which means that a high-quality and efficient single-photon source can be generated.

Controllable photonic and phononic topological state transfers in a small optomechanical lattice.

We propose a scheme to achieve the photonic and the phononic state transfers via the topological protected edge channel based on a one-dimensional small optomechanical lattice. We find that the optomechanical lattice can be mapped into a Su-Schrieffer-Heeger model after eliminating the counter rotating wave terms. By dint of the edge channel of the Su-Schrieffer-Heeger model, we show that the quantum state transfer between the photonic left and the right edge states can be achieved with a high fidelity.

Temperature-resistant generation of robust entanglement with blue-detuning driving and mechanical gain.

We present a proposal to generate robust optomechanical entanglement induced by the blue-detuning laser and the mechanical gain in a double-cavity optomechanical system. We show that the stability of the system can be obtained by introducing a cavity mode driven by the red-detuning laser in the blue-detuning regime. In contrast to the red-detuning regime, we find that the entanglement in the blue-detuning regime is extremely robust to temperature.

Ground-state cooling of mechanical oscillator via quadratic optomechanical coupling with two coupled optical cavities.

We present a scheme for the electromagnetically induced transparency (EIT)-like nonlinear ground-state cooling in a double-cavity optomechanical system in which an optical cavity mode is coupled parametrically to the square of the position of a mechanical oscillator, an additional auxiliary cavity is coupled to the optomechanical cavity. The optimum cooling conditions is derived, based on which the heating process can be well suppressed and the mechanical resonator can be cooled with an optimal effect to near its ground state through EIT-like cooling mechanism even in unresolved sideband regime. It is demonstrated by numerical simulations that not only the average phonon number of steady state is lower than that of single-cavity optomechanical system, but also the cooling rate is greatly faster than that of the linear optomechanical coupling due to the two-phonon cooling process in the quadratic coupling.

Counterfactual entanglement swapping enables high-efficiency entanglement distribution.

We propose an alternative entanglement swapping scheme based on the principle of the counterfactual quantum communication, which demonstrates nonlocal entanglement swapping can be achieved by the operations of a third party. During the whole process, it is not needed to transmit any physical particles among the participants. Furthermore, all the entangled particles are not destroyed in the counterfactual entanglement swapping process, which means we can obtain two pairs of nonlocal entanglement at the same time, thus achieve high-efficiency entanglement distribution.

Controllable photonic and phononic edge localization via optomechanically induced Kitaev phase.

Experimental realization of the Kitaev model is a greatly attractive topic due to the potential applications to build robust qubits against decoherence in topological quantum computation. In this work, we investigate the charged whispering-gallery microcavity array model and simulate the normal Kitaev chain under this mechanism in the first time. We find that the system reveals profound connections with the normal Kitaev chain and its some derivatives, and the topological property of the system depends on effective optomechanical coupling strength deeply.

Ground-state cooling of rotating mirror in double-Laguerre-Gaussian-cavity with atomic ensemble.

A scheme is proposed to cool a rotating mirror close to its ground state in a double-Laguerre-Gaussian-cavity optomechanical system, where an auxiliary cavity and a two-level atomic ensemble simultaneously couple to the original optomechanical cavity. By choosing parameters reasonably, we find that the cooling process of the rotating mirror can be strengthened greatly while the heating process can be suppressed effectively. We show that the proposed ground-state cooling scheme can work well no matter whether in the weak or strong coupling regime for the atomic ensemble and original cavity.

Generation of steady entanglement via unilateral qubit driving in bad cavities.

We propose a scheme for generating an entangled state for two atoms trapped in two separate cavities coupled to each other. The scheme is based on the competition between the unitary dynamics induced by the classical fields and the collective decays induced by the dissipation of two non-local bosonic modes. In this scheme, only one qubit is driven by external classical fields, whereas the other need not be manipulated via classical driving.

Spraying Brassinolide improves Sigma Broad tolerance in foxtail millet (Setaria italica L.) through modulation of antioxidant activity and photosynthetic capacity.

To explore the role of Brassinolide (BR) in improving the tolerance of Sigma Broad in foxtail millet (Setaria italica L.), effects of 0.1 mg/L of BR foliar application 24 h before 3.

Simulating Z topological insulators via a one-dimensional cavity optomechanical cells array.

We propose a novel scheme to simulate Z topological insulators via one-dimensional (1D) cavity optomechanical cells array. The direct mapping between 1D cavity optomechanical cells array and 2D quantum spin Hall (QSH) system can be achieved by using diagonalization and dimensional reduction methods. We show that the topological features of the present model can be captured using a 1D generalized Harper equation with an additional SU(2) guage structure.