The quantum blockade effect is one of the important control methods for various quantum states. Recently, magnon has gradually become the focus of quantum device research due to its excellent properties such as stability, high spin density, and tunability. This study investigates the generation of conventional and unconventional single and double magnon blockades, as well as magnon-induced tunneling effects, in strongly nonlinearly coupled cavity–magnon systems. By adjusting the coupling strength and the driving field, we achieved single and double magnon blockades, along with magnon-induced tunneling effects. Interestingly, we found that the transition from a magnon blockade to magnon-induced tunneling can be controlled by modulating the driving field. To validate the feasibility of our model, we examined the impact of thermal noise at an experimental temperature of 20 mK. Our proposed scheme may offer a method to manipulate few-magnon states and holds potential applications in quantum communication and quantum information processing.
The quantum blockade effect is one of the important control methods for various quantum states. Recently, magnon has gradually become the focus of quantum device research due to its excellent properties such as stability, high spin density, and tunability. This study investigates the generation of conventional and unconventional single and double magnon blockades, as well as magnon-induced tunneling effects, in strongly nonlinearly coupled cavity–magnon systems. By adjusting the coupling strength and the driving field, we achieved single and double magnon blockades, along with magnon-induced tunneling effects. Interestingly, we found that the transition from a magnon blockade to magnon-induced tunneling can be controlled by modulating the driving field. To validate the feasibility of our model, we examined the impact of thermal noise at an experimental temperature of 20 mK. Our proposed scheme may offer a method to manipulate few-magnon states and holds potential applications in quantum communication and quantum information processing.
Magnon blockade is an effective physical mechanism to generate a single magnon, which is of great importance in quantum information processing. We present a scheme to realize the unconventional magnon blockade effect by using Kerr nonlinearity in a cavity electromagnonic system. Under weak driving conditions, we give the optimal parameter conditions for magnon antibunching through analytical calculations, which are in good agreement with numerical results. Furthermore, we find that Kerr nonlinearity is necessary to create magnon blockade. In particular, unconventional magnon blockade can be achieved in both weak nonlinearity and weak coupling regimes. The present scheme indicates a method for generating unconventional magnon blockade effect and provides a feasible and flexible platform for the realization of a single-magnon source with high purity.
Abstract Magnon blockade (MB) is a fundamental quantum phenomenon for generating single-magnon states, and has gradually become one of the candidates for quantum information processing. We extend existing blockade optimization schemes to a hybrid system consisting of a YIG micromagnet and a skyrmion, and propose a theoretical scheme for achieving MB on this platform. Under weak magnon probing and external driving of the skyrmion qubit, the second-order correlation function is analytically derived, and the optimal parameter conditions for both conventional and unconventional MB are identified. By appropriately adjusting the intensities of the driving and probing fields, the MB effect is significantly enhanced, multi-magnon excitations are effectively suppressed, and strong antibunching is achieved. Further analysis reveals that MB originates from two distinct physical mechanisms: conventional blockade induced by anharmonicity of the energy level structure, and unconventional blockade arising from quantum interference between different transition paths. On this platform, the two mechanisms coexist and can be synergistically controlled, and their cooperation yields a blockade effect superior to that of either mechanism alone. This work thus provides a feasible theoretical scheme for the effective manipulation of MB effects.
Manipulating the cavity-magnon polariton blockade is significant for achieving precise, on-demand control of individual photons (magnons) and has particular applications in realizing multifunctional quantum technologies, quantum information processing, and hybrid quantum networks. In this paper, we theoretically propose a scheme to realize an n-cavity-magnon polariton blockade in a cavity-magnon system by utilizing Kerr nonlinearity. We demonstrate that the Kerr nonlinearity introduces anharmonicity into the polariton energy spectrum, which in turn enables the blockade effect. When the external driving frequency is resonant with the transition to the nth polariton excited state, a perfect n-polariton blockade is achieved. Moreover, increasing the driving strength can enhance the higher-order blockade while maintaining high fidelity in a dissipative environment. Our work pioneers the field of cavity-magnon polariton blockade, opens a new avenue for the preparation of controllable quantum resources, and holds significant potential for applications in quantum communication and quantum information processing.
Magnons, as quasiparticles arising from spin wave excitations in magnetic materials, have demonstrated significant application potential in quantum information technology, spintronics, and microwave engineering in recent years. The cavity magnon optomechanical system, serving as a key platform for investigating magneto-optical interactions, has advanced the exploration of nonlinear dynamical behaviors and the innovative design of quantum devices through strong coupling between magnons, photons, and phonons. However, traditional single-cavity systems face limitations in terms of tunability, long-range interactions, and nonlinear enhancement, making them insufficient for complex quantum control requirements. In recent years, dual-cavity systems have become a research hotspot due to their multidimensional control capabilities achieved through inter-cavity coupling, such as photon mode splitting and enhanced nonlinear Kerr effects. Meanwhile, semiconductor quantum dots, provide a novel pathway for regulating magnon dynamics due to their tunable nonlinear response characteristics. In this work, we construct a novel coupled quantum system by integrating quantum dots and a dual-cavity architecture, and investigate the bistable phenomena under both forward and backward driving field inputs. By comparing the third-order nonlinear equations governing magnon populations in the two scenarios, we derive the impedance matching condition. When this condition is satisfied, the magnon responses induced by forward driving field and backward driving field are identical. Conversely, under impedance mismatch, the magnon responses exhibit different behaviors. Specifically, when the impedance matching condition is violated, the dual-cavity magnon optomechanical system incorporating three-level quantum dot molecules exhibits a lower bistability threshold than its counterpart without quantum dots. This allows for a transition from low steady state to high steady state while reducing the driving field strength, thereby achieving switching functionality at lower input power. Furthermore, we establish a multiparameter cooperative control model, revealing a three-dimensional parameter space formed by tunneling coupling, cavity-quantum dot coupling, and inter-cavity coupling. By adjusting these coupling strengths, the bistability threshold and hysteresis loop width can be effectively controlled, thereby modulating the driving field intensity required for bistability. This system is expected to experimentally observe the magnonic bistability through the vector network analyzer-based detection of abrupt changes in transmission or absorption windows in reflection spectra. Such capabilities can advance data signal transmission, switching devices, and memory technologies, and has the potential to serve as components of large-scale quantum information processing units. Additionally, this research may find important applications in the field of magnetic spintronics.
We study the multimagnon blockade and magnon-induced tunneling in the hybrid ferromagnet-superconductor system, where a magnon mode representing the collective motion of spins in the yttrium iron garnet (YIG) sphere is coupled with a three-level $\mathrm{\ensuremath{\Delta}}$-type fluxonium qubit via the virtual-photon excitation from the microwave cavity. By appropriately choosing the parameters, the single magnon blockade, multimagnon blockade including two- and three-magnon blockades, and magnon-induced tunneling could be achieved. Fortunately, the switch from magnon blockade to magnon-induced tunneling could be obtained via controlling the overall phase of the loop transition determined by the driving fields. Furthermore, the single-magnon blockade could be transformed into a multimagnon blockade via the phase modulation. The scheme we present may provide an alternative method to manipulate the few-magnon states and have potential applications in quantum communication and quantum information processing.
We investigate magnon statistics in a qubit-magnon hybrid quantum system in which an effective appreciable qubit-magnon coupling can be realized by exchanging virtual cavity photons. A conventional magnon blockade and two types of unconventional magnon blockades are proposed, respectively, based on three different physical mechanisms. We verify theoretically that a magnon blockade can occur in strong, weak, and moderate qubit-magnon coupling regimes. It is interesting that an asymmetry structure for magnon anti-bunching can be observed in the case of the moderate qubit-magnon coupling strength, especially where the quantum interference can significantly relax the requirement of the larger coupling strength between the qubit and magnon mode. All of the approximate analytical results for strong magnon anti-bunching are in good agreement with those obtained by numerical simulations. Our results provide a promising pathway for coherent manipulation in single magnon level, which has potential applications for quantum information processing and preparation of single magnon sources.