Search

We propose a scheme for achieving magnon antibunching in a hybrid ferromagnet–superconductor system, where the magnons excited in two yttrium iron garnet (YIG) spheres couple the different levels of a cyclic three-level superconducting qubit by eliminating two perpendicular microwave cavity modes. With the aid of the three-level system, we find that the magnon antibunching can be achieved in a weak coupling regime via the degenerate three-wave mixing process. Moreover, it is found that the magnon antibunching inside a YIG2 sphere can be effectively regulated by manipulating the YIG1 sphere, for instance, the coupling strength of the YIG1 sphere and qubit and the driving strengths of the system. This work provides an alternative scheme for constructing the single magnon source based on the ferromagnet–superconductor technology and is conducive to studying the quantum properties of magnons.

The sign of quantum interference (constructive or destructive) based on cavity optomechanics is crucial for observing quantum phenomena and designing high-sensitivity sensors with an integrable structure. Here, we propose an efficient scheme to generate constructive interference and optomechanically induced absorption (OMIA) in a hybrid atom–cavity optomechanical system. Using experimentally achievable parameters, we theoretically demonstrate that a gain-type OMIA dip with the extremely narrow linewidth and the enhanced spectral intensity can be modulated by an assisted atom that is excited by an external control field. More importantly, we report that a precise mass sensor is achieved by employing an observable correlation between the OMIA dip and the added mass deposited on the mechanical object. With the help of the back-action cooling of the mechanical object, we identify that the detection sensitivity and minimum resolution of the mass sensor can reach 3.14 MHz / ng and 1 fg, respectively.

We investigate the coherent control of the transmission spectrum in a cavity magnetomechanical system consisting of microwave photon, magnon, and phonon modes, where the microwave cavity is driven by a strong pump field and a weak probe field, and the magnon is driven by a weak microwave source. Different from a single transparency window in the absence of the phonon–magnon interaction, two transparency windows and three absorption dips can be observed in the presence of the phonon–magnon interaction, which originates from the joint interaction of phonon–magnon and photon–magnon. In addition, two absorption dips located at both sides of the central absorption dip can be modulated asymmetrically into amplification and absorption by varying the magnetic field amplitude of the magnon driving field. Interestingly enough, the relative phase of applied fields could have profound effects on both the transmission spectrum and the group delay of the output field by choosing the appropriate magnetic field amplitude of the magnon driving field. The transmission group delay can be switched between positive to negative and vice versa by adjusting the relative phase between the applied fields. The present results illustrate the potential to utilize the relative phase for controlling the microwave signal in the cavity magnomechanical system, as well as guidance in the design of information transduction and quantum sensing.

A scheme of enhanced Goos-Hanchen (GH) shifts in reflected and transmitted light beams is exploited in a cavity, where an asymmetric double AlGaAs/GaAs quantum well structure with resonant tunneling to a common continuum is employed as the intracavity medium. With the help of Fano-type interference induced by resonant tunneling, the generated GH shifts that contain a negative lateral shift in reflected light beam and a positive lateral shift in transmitted light beam are found to be significantly enhanced. More interestingly, these GH shifts in reflected and transmitted light beams are modulated by means of a control beam and external bias voltage, in which maximum negative shift of 1.86 mm and positive shift of 0.37 mm are achievable.

We investigate the light propagation and dynamical control of a weak pulsed probe field in asymmetric double quantum wells via Fano interference, which is caused by tunneling from the excited subbands to the same continuum. Our results show that the system can produce anomalous and normal dispersion regions with negligible absorption by choosing appropriate coupling strength of the tunneling and the Fano interference. Interesting enough, the dispersion can be switched between normal and anomalous by adjusting the relative phase between the pulsed probe and coherent control fields owing to the existence of the perfectly Fano interference. Thus, the relative phase can be regarded as a switch to manipulate light propagation with subluminal or superluminal. The temporal and spatial dynamics of the pulsed probe field with hyperbolic secant envelope are analyzed.

We theoretically study the ultrafast transfer of a single electron between the ground states of a coupled double quantum dot (QD) structure driven by a nonlinear chirped few-cycle laser pulse. A time-dependent Schrodinger equation without the rotating wave approximation is solved numerically. We demonstrate numerically the possibility to have a complete transfer of a single electron by choosing appropriate values of chirped rate parameters and the intensity of the pulse. Even in the presence of the spontaneous emission and dephasing processes of the QD system, high-efficiency coherent transfer of a single electron can be obtained in a wide range of the pulse parameters. Our results illustrate the potential to utilize few-cycle pulses for the excitation in coupled quantum dot systems through the nonlinear chirp parameter control, as well as a guidance in the design of experimental implementation.