作者机构：
[Hu, Xiangming; Gou, Chengdeng] Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Peoples R China.
通讯机构：
[Hu, XM ] C;Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Peoples R China.
摘要：
In this paper we propose a scheme for achieving simultaneous nonreciprocal photon blockade for two coupled spinning resonators, one of which contains an optical parametric amplifier (OPA). Rotating two resonators gives rise to opposite Sagnac-Fizeau shifts for input from different ends. Depending on the opposite shifts, quantum destructive interference emerges and disappears in two-photon excitation. The emergence of destructive interference results in photon blockade in two resonators simultaneously for one end input, while the lack of complete destructive interference makes the blockade disappear for the other end input. The simultaneous nonreciprocal blockade is tunable by controlling the amplitude of the probe field and the driving field applied on the OPA. Our work paves the way to develop simultaneous nonreciprocal single-photon devices in multiple modes, which have potential applications in multichannel topological and chiral quantum technologies.
期刊：
Results in Physics,2023年52:106818 ISSN：2211-3797
通讯作者：
Hu, XM;Wang, Fei;Kong, DY
作者机构：
[Xu, Jun; Hu, Xiangming] Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Peoples R China.;[Kong, Deyi; Wang, Fei; Wang, F] Hubei Univ Technol, Sch Sci, Wuhan 430068, Peoples R China.
通讯机构：
[Kong, DY ; Wang, F] H;[Hu, XM ] C;Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Peoples R China.;Hubei Univ Technol, Sch Sci, Wuhan 430068, Peoples R China.
关键词：
Higher-order squeezing;Magnon;Superconducting artificial atom
摘要：
We propose an efficient scheme to realize almost perfect higher-order squeezing of two YIG spheres via microwave-mediated magnon–atom interactions. It is assumed that two microwave cavity modes are coupled to two YIG spheres by the magnetic dipole interaction and a superconducting artificial atom by the electric dipole interaction, respectively. When the microwave cavity fields are tuned to be far detuned from the dressed atomic Rabi sidebands and the magnon frequencies, the coherent coupling between two magnons and the artificial atom can be established via virtual photon exchange. We find that a pair of Bogoliubov modes composed of two magnon modes are cooled to the vacuum state through the atomic engineered dissipation, resulting in an ideal two-mode higher-order squeezing state of the YIG spheres. The solid-state device may find realistic applications in high-precision measurement and quantum sensing technology.
期刊：
New Journal of Physics,2023年25(6):063016 ISSN：1367-2630
通讯作者：
Hu, XM
作者机构：
[Hu, Xiangming; Chen, Junyu; Xu, Jun; Hu, Liang; Kong, Deyi] Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Peoples R China.
通讯机构：
[Hu, XM ] C;Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Peoples R China.
关键词：
spin two-axis-twisting;coherent population trapping;cavity QED
摘要：
We present a spin two-axis-twisting mechanism via coherent population trapping (CPT) based atom–photon interactions. CPT happens and the atoms are trapped in the dark state (coherent superposition of two ground states) when the ground states are resonantly coupled to a common excited state. Close to CPT, the atoms behave as two dark-state based spins, which interact with the common cavity vacuum fields. The otherwise nonexistent interaction is created between them and is identified to be responsible for the two-axis-twisting of the ground state spin. The essential difference from the previous schemes is the compatibility of the twisting spin squeezing with the resonant atom-light interaction. The CPT resonant unit serves as a kind of new ingredients for the quantum networks.
作者机构：
[Wang, Fei] Hubei Univ Technol, Sch Sci, Wuhan 430068, Hubei, Peoples R China.;[Wang, Chaowen; Hu, Xiangming; Shen, Kang] Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Hubei, Peoples R China.;[Wang, Chaowen] China Three Gorges Univ, Coll Sci, Yichang 443002, Hubei, Peoples R China.
关键词：
Four wave mixing;Quantum cryptography;Quantum information processing;Raman lasers;Spontaneous emission;Two level systems
摘要：
In this paper, we reexamine the quantum correlations in a four-state single-atom system in the weak coupling regime, aiming at the realization of stable entanglement and one-way steering via dissipation rather than coherent evolution process. Under the near-resonant conditions, we find out that a single atom can act as a reservoir and behave like a two-level system with a single dissipation channel, through which the composite Bogoliubov mode will evolve into a vacuum state, resulting in the appearance of stationary entanglement between two original modes. In addition, the one-way steering is generated when the symmetry is broken by choosing asymmetrical coupling constants. The present scheme may provide convenience tor experimental implement and find applications in quantum information processing. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement
作者机构：
[Gong, Cheng; Xu, Jun; Hu, Xiangming; Kong, Deyi] Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Peoples R China.;[Wang, Fei] Hubei Univ Technol, Sch Sci, Wuhan 430068, Peoples R China.
关键词：
Magnetic fields;Photonic entanglement;Quantum communications;Quantum cryptography;Quantum networks;Whispering gallery modes
摘要：
We show that it is possible to generate magnon-atom-optical photon tripartite entanglement via the microwave photon-mediated Raman interaction. Magnons in a macroscopic ferromagnet and optical photons in a cavity are induced into a Raman interaction with an atomic spin ensemble when a microwave field couples the magnons to one Raman wing. The controllable magnon-atom entanglement, magnon-optical photon entanglement, and even genuine magnon-atom-optical photon tripartite entanglement can be generated simultaneously. In addition, these bipartite and tripartite entanglements are robust against the environment temperature. Our scheme paves the way for exploring a quantum interface bridging the microwave and optical domains, and may provide a promising building block for hybrid quantum networks.
摘要：
In general, ionization-induced free-electron plasma is considered to increase spectral blueshift during femtosecond laser filamentation. Here we theoretically show that the enhancement of plasma density via avalanche ionization decreases the blueshift of supercontinuum (SC) spectra associated with a ultraviolet filament in fused silica. By numerically solving the forward Maxwell equations, our simulations show that the arrest of beam collapse is ascribed to multiphoton absorption rather than plasma defocusing. In addition, SC spectral broadening is mainly dominated by Kerr self-phase modulation (SPM), while the plasma generated by ionization plays a more significant role in absorbing the laser pulse energy, which would suppress the Kerr SPM effect, than in reducing the refractive index. Our work provides a clearer understanding of ultraviolet laser propagation dynamics in condensed media. (c) 2022 Optica Publishing Group
作者机构：
[Hu, Xiangming; Xu, Jun; Hu, Liang; Kong, Deyi] Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Peoples R China.
摘要：
In general, a magnon does not interact directly with an atom. Here we present a scheme to generate coherent coupling between two magnons and a superconducting artificial atom via exchange of virtual photons in dispersive cavities. By probing into the induced magnon-atom interactions, we identify the two-magnon process, which causes almost perfect two-mode squeezing and entanglement of the two magnons for specific conditions. The quantum entanglement of the magnon modes in two massive ferrimagnets survives at the steady state and represents genuinely macroscopic quantum state. Our work offers an interesting alternative in designing experiments for generating the coherent coupling between the magnons and the atom. It finds broad applications in the investigation of macroscopic quantum effects and the preparation of quantum devices.
摘要：
In this paper, we investigate the light-bullet dynamics during femtosecond laser filamenation in an anomalous dispersion regime based on the experimentally observed blueshifted resonant radiation (RR) in fused silica. A numerical simulation is performed and well reproduces the pronounced asymmetric feature of the RR spectra. By applying a time-frequency analysis to the propagating laser field, this specific spectral feature is found to be closely connected to the positively chirped property of RR in the time domain. In the context of the effective three-wave mixing model, this temporal chirp character of the RR is ascribed to the variable phase-matching conditions, which can be traced back to the accelerative propagation of the light bullet during its formation. Our work provides a deep understanding of the spatiotemporal dynamics of femtosecond laser-pulse propagation in condensed media.
