We propose a theoretical scheme for realizing a tunable nonreciprocal Goos-Hänchen shift (GHS) in a hybrid cavity magnomechanical system. The setup consists of a rotating yttrium iron garnet sphere embedded in a microwave cavity, with magnetic-dipole and magnetostrictive interactions mediating magnon-photon and magnon-phonon couplings, respectively. Owing to the Barnett effect, the magnon frequency acquires a rotation-induced shift whose sign can be reversed by changing the direction of the bias magnetic field. We show that the output probe spectrum exhibits a Fano resonance, while the associated GHS responds asymmetrically to opposite field directions, providing a controllable mechanism for nonreciprocal beam shifts. The magnon-photon and magnon-phonon interactions are found to affect the GHS in opposite ways, while the cavity length offers an additional degree of tunability. These results provide a route toward magnetically reconfigurable microwave photonic devices and sensitive detection of Barnett-induced effective fields.
We propose a scheme to manipulate the Goos-Hänchen shift (GHS) of a reflected probe field in a non-Hermitian cavity magnomechanical system. The platform consists of a yttrium-iron-garnet sphere coupled to a microwave cavity, where a strong microwave drive pumps the magnon mode and a weak field probes the cavity. The traveling field's interaction with the magnon induces gain, yielding non-Hermitian dynamics. When the traveling field is oriented at
π/2 relative to the cavity's
x-axis, the system realizes
PT symmetry; eigenvalue analysis reveals a third-order exceptional point (
EP3) at a tunable effective magnon-photon coupling. Under balanced gain-loss and finite effective magnomechanical coupling, we demonstrate coherent control of the GHS by steering the system across the
PT-symmetric transition and through
EP3 via the effective magnon-photon coupling, enabling pronounced enhancement or suppression of the lateral shift. Furthermore, we show that without effective magnomechanical coupling, the system exhibits a second-order exceptional point (
EP2) with a distinct GHS phase transition. This phase transition vanishes when the effective magnomechanical coupling exceeds a parametric threshold, where strong absorption at resonance suppresses the GHS. We also identify the intracavity length as an additional control parameter for precise shift tuning. Notably, the
PT-symmetric configuration yields substantially larger GHS than its Hermitian counterpart. These results advance non-Hermitian magnomechanics and open a route to GHS-based microwave components for quantum switching and precision sensing.
We theoretically propose a scheme for achieving nonreciprocal bipartite and tripartite entanglement among magnons, photons, and phonons utilizing the Barnett effect in a cavity magnomechanical (CMM) system where a rotating yttrium iron garnet sphere is placed in a microwave cavity. The Barnett effect induces a Barnett frequency shift that can be effectively controlled to be either positive or negative by adjusting the direction of the magnetic field. As a result, nonreciprocal bipartite and tripartite entanglement can be achieved, exhibiting robustness against the bath temperature. Our work provides a very accessible way to manipulate photon-magnon-phonon quantum resources based on CMM devices with the Barnett effect.
We propose a scheme for realizing nonreciprocal bipartite and tripartite entanglement in a hybrid cavity optomagnonic system. The system consists of a tunable Fabry-Perot (FP) cavity and a microwave cavity, an yttrium iron garnet slab (YIG1) and a rotating yttrium iron garnet sphere (YIG2). The magnon modes in both YIG1 and YIG2 are strongly coupled to the microwave cavity mode, and the magnon mode in YIG1 also has a three-mode resonant interaction with the optical modes in the FP cavity. The Barnett effect causes a frequency shift of the magnon mode in YIG2. By reversing the external bias magnetic field of YIG2 to control the sign of the Barnett frequency shift, one can not only switch the entanglement partner of the optical mode between the magnon and microwave modes, but also achieve perfect on-off control of bipartite optical-microwave entanglement and tripartite optical-magnon-microwave entanglement. The study presents a flexible control scheme to realize nonreciprocal bipartite and tripartite entanglement in quantum nodes that integrate diverse physical systems such as optics, magnons, and microwaves, and may have potential applications in entanglement-based quantum networks.
We theoretically investigate the quantum coherence ans its nonreciprocity in a cavity magnomechanical (CMM) syetem, which consists of a rotating yittrium iron garnet (YIG) sphere and a microwave cavity. By adjusting the direction of the magnetic field, the frequency shift of a magnon mode can be tuned from positive to negative due to the Barnett effect. This effect leads to a significant difference in the system stability and is responsible for the nonreciprocal quantum coherence. We examine how the input power, magnomechanical and magnon-photon coupling rates, decay rates of both the cavity photon modes and the magnon modes influence the quantum coherence. Through careful tuning of system parameters, nearly perfect nonreciprocity can be achieved. Our results provide a controllable mechanism for direction-dependent quantum coherence, with potential applications in nonreciprocal quantum devices and information processing.
Nonreciprocal phenomena are currently a major focus of research within the fields of classical and quantum technology. In this work, we theoretically investigate the interplay among multiple magnomechanically induced transparency (MMIT) windows, Fano resonances, slow/fast light, and nonreciprocal absorption and group delay in a hybrid cavity magnomechanical system. This system is composed of two yttrium iron garnet (YIG) spheres and a membrane positioned at the center of the cavity. By analyzing the absorption spectrum of a weak probe field in the presence of a strong control field, we demonstrate the emergence of five transparency windows resulting from combined photon-phonon, photon-magnon, and phonon-magnon interactions. The photon-phonon coupling associated with the membrane plays a crucial role in enhancing and tailoring these transparency features. We further examine the impact of the Barnett effect on the absorption and dispersion characteristics, showing that it enables the controllable manipulation of transparency windows and the generation of tunable Fano resonance profiles. The influence of cavity decay and magnon dissipation rates on the spectral response is also analyzed. In addition, we demonstrate that the group delay of the transmitted probe field can be effectively tuned via the photon-phonon coupling strength and the Barnett effect, allowing for a controllable transition between slow and fast light regimes. Finally, nonreciprocal absorption and group delay are achieved through appropriate adjustment of the coupling parameters. These findings highlight the potential of the proposed hybrid system for applications in optical signal processing and quantum information technologies.
ABSTRACT We propose a scheme for realizing nonreciprocal photon–phonon entanglement in a hybrid cavity magnomechanical system, where the Barnett effect and the Sagnac effect are used. By changing the rotation direction of the cavity field and the direction of the bias magnetic field or the direction of rotation of the YIG sphere, we can induce an opposite Sagnac–Fizeau frequency shift on the cavity and a Barnett frequency shift of the magnon mode, which lead to nonreciprocity. Our results indicate that through selecting appropriate parameters, such as frequency detuning or magnomechanical coupling strength or bath temperature, the nonreciprocity of photon–phonon entanglements in this system can be correspondingly manipulated (such as switched off or on). And through combining the Barnett effect with the Sagnac effect, the entanglement nonreciprocity can be significantly enhanced. We find that nonreciprocal entanglement exhibits excellent tolerance to elevated bath temperature. Our paper provides a promising approach for engineering various nonreciprocal devices with the Barnett and the Sagnac effects.