Searcharxiv⌕ Search

arXiv subjects

Shao-Xiong Wu

Publications and source records attributed to Shao-Xiong Wu.

8 recordsLinked to original sources
arXiv2026

Nonreciprocal Photon Blockade in an Asymmetric Cavity

We propose a scheme to realize tunable and strong nonreciprocal photon blockade (PB) in an asymmetric Fabry-Pérot cavity. The setup consists of a single-mode optical cavity trapping a two-level atom, with the cavity coherently driven by a laser and the atom pumped by an auxiliary control field of the same frequency. By engineering quantum interference between multiple excitation pathways by adjusting the amplitude and relative phase of the control laser, we identify two distinct optimal control conditions that enable directional suppression of two-photon states. Under optimal control conditions, strong nonreciprocal PB is achieved, with a nonreciprocal ratio exceeding 30 dB over a broad operational bandwidth. The proposed protocol requires only standard coherent laser sources and is compatible with current cavity QED experimental setups, offering a practical and scalable platform for nonreciprocal quantum photonics.

quant-ph↗
arXiv2025

Generating strong mechanical squeezing via combined squeezed vacuum field and two-tone driving

We propose a novel scheme for generating mechanical squeezed states based on the combined mechanism of a two-tone driving and a squeezed vacuum field. This innovative approach achieves a remarkable improvement in mechanical squeezing performance across the entire range of red/blue detuning ratios. Our study reveals that the squeezed vacuum field not only induces position squeezing of the mechanical oscillator but also facilitates momentum squeezing through phase matching. Moreover, the total squeezing degree exhibits nonlinear enhancement with the increasing of squeezing parameter $r$. The mechanical squeezed state exhibits a $2π$-periodic dependence in relation to the squeezing phase $θ$, offering experimental implementation with a high degree of operational flexibility. Notably, the scheme exhibits strong robustness against cavity dissipation and environmental thermal noise, substantially relaxing the strict parameter-matching requirements inherent in conventional approaches.

quant-ph↗
arXiv2025

Nonreciprocal photon blockade induced by parametric amplification in an asymmetrical cavity

We propose a scheme to generate and manipulate nonreciprocal photon blockade effect in an asymmetrical Fabry-Pérot cavity, which consists of a single two-level atom and a second-order nonlinear medium. By utilizing the intrinsic spatial asymmetry of cavity and applying a parametric amplification pumping laser to the nonlinear medium, we can realize direction-dependent single-photon and two-photon blockade effects. For nonreciprocal single-photon blockade, our proposal is robust across a wide range of parameters, such as the cavity or atomic detuning, coupling strength, and atomic decay. Within similar parameter ranges, nonreciprocal two-photon blockade can be achieved and modulated by finely adjusting the parametric amplification pumping. Our project offers a feasible access to generating high-quality and tunable nonreciprocal single/two-photon source and paves a new avenue for investigating the nonreciprocity of photon quantum statistical properties.

quant-ph↗
arXiv2024

Generation of strong mechanical squeezing through the joint effect of two-tone driving and parametric pumping

We propose an innovative scheme to efficiently prepare strong mechanical squeezing through utilizing the synergistic mechanism of two-tone driving and parametric pumping in an optomechanical system. By reasonable choosing the system parameters, the proposal highlights the following prominent advantages: the squeezing effect of the cavity field induced by the optical parametric amplifier can be transferred to the mechanical oscillator, which has been squeezed by the two-tone driving, and the degree of squeezing of the mechanical oscillator will surpass that obtained by any single mechanism; the joint mechanism can enhance the degree of squeezing significantly and break the 3 dB mechanical squeezing limit, which is particularly evident in range where the red/blue-detuned ratio is sub-optimal; the mechanical squeezing achieved through this distinctive joint mechanism exhibits notable robustness against both thermal noise and decay of mechanical oscillator. Our project offers a versatile and efficient approach for generating strong mechanical squeezing across a wide range of conditions.

quant-ph↗
arXiv2023

Quantum squeezing induced quantum entanglement and EPR steering in coupled optomechanical system

We propose a theoretical project in which quantum squeezing induces quantum entanglement and Einstein-Podolsky-Rosen steering in a coupled whispering-gallery-mode optomechanical system. Through pumping the $χ^{(2)}$-nonlinear resonator with the phase matching condition, the generated squeezed resonator mode and the mechanical mode of the optomechanical resonator can generate strong quantum entanglement and EPR steering, where the squeezing of the nonlinear resonator plays the vital role. The transitions from zero entanglement to strong entanglement and one-way steering to two-way steering can be realized by adjusting the system parameters appropriately. The photon-photon entanglement and steering between the two resonators can also be obtained by deducing the amplitude of the driving laser. Our project does not need an extraordinarily squeezed field, and it is convenient to manipulate and provides a novel and flexible avenue for diverse applications in quantum technology dependent on both optomechanical and photon-photon entanglement and steering.

quant-ph↗
arXiv2023

Quantum speed limit of a single atom in a squeezed optical cavity mode

We theoretically study the quantum speed limit of a single atom trapped in a Fabry-Perot microresonator. The cavity mode will be squeezed when a driving laser is applied to the second-order nonlinear medium, and the effective Hamiltonian can be obtained under the Bogoliubov squeezing transformation. The analytical expression of evolved atom state can be obtained by using the non-Hermitian Schrödinger equation for the initial excited state, and the quantum speed limit time coincides very well for both the analytical expression and the master equation method. From the perspective of quantum speed limit, it is more conducive to accelerate the evolution of the quantum state for the large detuning, strong driving and coupling strength. For the initial superposition state case, the form of initial state has more influence on the evolution speed. The quantum speed limit time is not only dependent on the system parameters but also determined by the initial state.

quant-ph↗
arXiv2023

Enhancing the quantum entanglement and EPR steering of a coupled optomechanical system with a squeezed vacuum field

Quantum entanglement and Einstein-Podolsky-Rosen (EPR) steering are valuable resources in quantum information processing. How to enhance the quantum entanglement and EPR steering of coupled optomechanical systems with a weak squeezed vacuum field are studied when the displacement of detuning induced by the mechanical mode is considered. Compared with the condition that the system interacts with a vacuum environment, the quantum entanglement and EPR steering are stronger when the squeezed vacuum field is applied. A squeezed vacuum field with a large degree is not beneficial to enhance the quantum entanglement and EPR steering. Rather than the squeezing parameter of the squeezed vacuum field, the reference phase plays a vital role in this model.

quant-ph↗
arXiv2023

Photon blockade with a trapped $Λ$-type three-level atom in asymmetrical cavity

We propose a scheme to manipulate strong and nonreciprocal photon blockades in asymmetrical Fabry-Perot cavity with a $Λ$-type three-level atom. Utilizing the mechanisms of both conventional and unconventional blockade, the strong photon blockade is achieved by the anharmonic eigenenergy spectrum brought by $Λ$-type atom and the destructive quantum interference effect induced by a microwave field. By optimizing the system parameters, the manipulation of strong photon blockade over a wide range of cavity detuning can be realized. Using spatial symmetry breaking introduced by the asymmetry of cavity, the direction-dependent nonreciprocal photon blockade can be achieved, and the nonreciprocity can reach the maximum at optimal cavity detuning. In particular, manipulating the occurring position of nonreciprocal photon blockade can be implemented by simply adjusting the cavity detuning. Our scheme provides feasible access for generating high-quality nonreciprocal single-photon sources.

quant-ph↗