We investigate magnon–photon pair antibunching in a cavity optomagnonic system, in which a yttrium iron garnet sphere simultaneously supports two optical modes and a magnon mode and is driven by squeezed light and coherent light. The results illustrate that by applying squeezed light, the conventional magnon–photon pair blockade (CMPPB) originating from anharmonic energy levels and the unconventional magnon–photon pair blockade (UMPPB) induced by destructive quantum interference can coexist in the same platform. Both blockade effects can be flexibly tuned by the driving detuning and the optomagnonic coupling strength. Within the explored parameter regime, the UMPPB exhibits a nontrivial dependence on the driving strengths of coherent light and squeezed light, and bunching regions may also appear. These results provide a tunable framework for controlling magnon–photon pair antibunching, which may be useful for the generation and manipulation of hybrid nonclassical states in cavity optomagnonic systems.
We investigate magnon–photon pair antibunching in a cavity optomagnonic system, in which a yttrium iron garnet sphere simultaneously supports two optical modes and a magnon mode and is driven by squeezed light and coherent light. The results illustrate that by applying squeezed light, the conventional magnon–photon pair blockade (CMPPB) originating from anharmonic energy levels and the unconventional magnon–photon pair blockade (UMPPB) induced by destructive quantum interference can coexist in the same platform. Both blockade effects can be flexibly tuned by the driving detuning and the optomagnonic coupling strength. Within the explored parameter regime, the UMPPB exhibits a nontrivial dependence on the driving strengths of coherent light and squeezed light, and bunching regions may also appear. These results provide a tunable framework for controlling magnon–photon pair antibunching, which may be useful for the generation and manipulation of hybrid nonclassical states in cavity optomagnonic systems.
In this work, we study the phenomena of quantum-interference-assisted magnon blockade and magnon antibunching in a weakly interacting hybrid ferromagnet-superconductor system. The magnon excitations in two yttrium iron garnet spheres are indirectly coupled to a superconducting qubit through microwave cavity modes of two mutually perpendicular cavities. We find that when one of the magnon modes is driven by a weak microwave field, the destructive interference between more than two distinct transition pathways restricts the simultaneous excitation of two magnons. We analyze the magnon correlations in the driven magnon mode for the case of zero detunings as well as finite detunings of the magnon modes and the qubit. We show that the magnon antibunching can be tuned by changing the magnon-qubit coupling strength ratio and the driving detuning. Our work proposes a possible scheme that has a significant role in the construction of single magnon generating devices.
We propose a feasible experimental model to investigate the generation and characterization of nonclassical states in a cavity optomagnonic system consisting of a ferromagnetic YIG sphere that simultaneously supports both the magnon mode and two whispering gallery modes of optical photons. The photons undergo the magnon-induced Brillouin light scattering, which is a well-established tool for the cavity-assisted manipulations of magnons as well as magnon spintronics. At first, we derive the desired interaction Hamiltonian under the influence of the anti-Stokes scattering process and then proceed to analyze the dynamical evolution of quantum statistics of photons and magnons as well as their intermodal entanglement. The results show that both photons and magnons generally acquire some nonclassical features, e.g., the strong antibunching and anti-correlation. Interestingly, the system may experience the perfect photon and magnon blockade phenomena, simultaneously. Besides, the nonclassical features may be protected against the unwanted environmental effects for a relatively long time, especially, in the weak driving field regime and when the system is initiated with a small number of particles. However, it should be noted that some fast quantum-classical transitions may occur in-between. Although the unwanted dissipative effects plague the nonclassical features, we show that this system can be adopted to prepare optomagnonic entangled states. The generation of entangled states depends on the initial state of the system and the interaction regime. The intermodal photon-magnon entanglement may be generated and pronounced, especially, if the system is initialized with low intensity even Schrödinger cat state in the strong coupling regime. The cavity-assisted manipulation of magnons is a unique and flexible mechanism that allows an interesting test bed for investigating the interdisciplinary contexts involving quantum optics and spintronics. Moreover, such a hybrid optomagnonic system may be used to design both on-demand single-photon and single-magnon sources and may find potential applications in quantum information processing.
Abstract We study the magnon antibunching effect in the magnon-qubit coupling system under the joint action of coherent and parametric drives. The analysis and numerical results reveal the conventional magnon blockade (CMB) caused by the anharmonic level splitting induced by strong magnon–qubit coupling and the unconventional magnon blockade (UMB) induced by multipath destructive interference. Notably, in the strong-coupling regime, substituting the CMB condition into the optimal UMB condition yields a phase-tuned CMB-constrained UMB condition, which simultaneously realizes strong magnon antibunching and a high single-magnon occupation probability. This combines the high brightness afforded by CMB with the high purity provided by UMB. Furthermore, in the weak-coupling regime, coordinated tuning of the phase, detuning, parametric drive, and coupling strength induces destructive interference among distinct excitation pathways, thereby yielding the UMB effect. Importantly, even in the zero-coupling limit, the additional channel provided by the parametric drive can sustain this blockade. This flexibility removes the reliance on stringent strong-coupling constraints, offering a viable route toward tunable strong magnon antibunching.
We explore a scheme to investigate the tunable magnon antibunching characteristics of the conventional magnon blockade (CMB) and the unconventional magnon blockade (UMB) in a hybrid ferromagnet-superconductor system. The magnon excited in the yttrium iron garnet is indirectly coupled to two qubits by eliminating two mutually perpendicular microwave cavity modes. In our paper, we relax the magnon-qubits detuning constraint. In two cases with and without magnon-qubits detuning, it is found that in the strong coupling regime CMB and UMB coexist in our system, and they can be regulated simultaneously by varying the magnon-qubits coupling strength ratio and the qubits detuning ratio. In the weak coupling regime, there exists only the UMB in the system. Without magnon-qubits detuning, the UMB shows a nonmonotonic dependence on the magnon-qubits coupling strength ratio. With magnon-qubits detuning, for the UMB, the magnon bunching effect and antibunching effect can be converted mutually by adjusting the magnon-qubits coupling strength ratio and the qubits detuning ratio. Moreover, changing the magnon-qubits coupling strength ratio and the qubits detuning ratio has a significant impact on the antibunching effect against the thermal magnon excitation. Our research results provide a theoretical scheme for the manipulation of magnon antibunching characteristics, and have important practical significance for the construction of a single magnon source.
We investigate unconventional magnon blockade (UMB) in a dissipative photon–magnon coupling cavity, where the coherent and dissipative coupling between photon and magnon can be adjusted by the position of the yttrium iron garnet sphere in the cavity. An approximate analytical solution for the statistical property of magnon is provided, which is in good agreement with the results obtained by numerically solving the Lindblad master equation. Our results indicate that UMB can be achieved in the case of dissipative photon–magnon coupling, but not in the case of coherent photon–magnon coupling. Secondly, by adjusting the amplitude of the external laser field, dynamic control of UMB can be achieved. Finally, by solving the Lindblad master equation containing the occupation number of thermal magnon and photon, the statistical properties of magnons will transition from nonclassical to classical. It is shown that the above phenomena originate from the interference between different quantum paths. Our research may provide theoretical possibilities for quantum manipulation schemes at the single-magnon level and open up a new avenue for designing single-magnon sources in a dissipative photon–magnon coupling system. • UMB can be generated by dissipative photon–magnon coupling, not coherent coupling. • The analytical optimal parameter for UMB is in agreement with the numerical result. • Dynamic-controlled UMB can be achieved by adjusting the external laser fields.
We propose a hybrid cavity-magnon system scheme that integrates a yttrium iron garnet sphere with a microwave cavity filled with Kerr medium, aiming to achieve both conventional and unconventional photon blockade simultaneously. Our research demonstrates that by tuning the strength of the Kerr nonlinearity and adjusting the two-photon driving intensity, we can realize quantum effects associated with both types of photon blockade. Furthermore, through careful selection of system parameters, we have obtained optimal results for photon blockade under ideal conditions. This scheme fully exploits the advantages offered by both conventional and unconventional photon blockade mechanisms, effectively reducing the equal-time second-order photon correlation function while also achieving a higher mean photon number. It provides an alternative and experimentally feasible platform for preparing single-photon sources characterized by enhanced purity and brightness.