On Transmission Efficiency of Quantum Modulations

Enhanced transmission capacity for laser communication at the single-photon level using the multi-channel frequency coding scheme

The statistical properties of a radiation sources are commonly characterized by second-order-correlation or Mandel parameter. Our research found that the single photons modulation spectrum provides us another optional way which is more sensitive to the high frequency information contained in the photon sequence. In this paper, we present direct laser communication by using a multi-channel frequency coding scheme based on the single photons modulation spectrum in which the multi-frequency modulation makes the transmission capacity efficiently enhanced. The modulation frequencies could be operat…

Adaptive Multicarrier Quadrature Division Modulation for Continuous-Variable Quantum Key Distribution

In a continuous-variable quantum key distribution (CVQKD) system, the information is conveyed by coherent state carriers. The quantum continuous variables are sent through a quantum channel, where the presence of the eavesdropper adds a white Gaussian noise to the transmission. The amount of tolerable noise and loss is a crucial point in CVQKD, since it determines the overall performance of the protocol, including the secure key rates and transmission distances. In this work, we propose the adaptive multicarrier quadrature division (AMQD) modulation technique for CVQKD. The method granulates t…

连续变量MIMO太赫兹量子秘密共享：高斯调制与被动调制

Continuous-Variable MIMO THz Quantum Secret Sharing: Gaussian-modulation and Passive-modulation

本文针对量子密钥分发无法支持多用户协作场景的局限，提出基于太赫兹频段MIMO架构的连续变量量子秘密共享协议，通过收发波束成形提高密钥生成率和传输距离，推导相关表达式并给出仿真结果，为评估该技术在无线网络中的性能提供理论基准。

Superconducting qubit in a nonstationary transmission line cavity: parametric excitation, periodic pumping, and energy dissipation

We consider a superconducting qubit coupled to the nonstationary transmission line cavity with modulated frequency taking into account energy dissipation. Previously, it was demonstrated that in the case of a single nonadiabatical modulation of a cavity frequency there are two channels of a two-level system excitation which are due to the absorption of Casimir photons and due to the counterrotating wave processes responsible for the dynamical Lamb effect. We show that the parametric periodical modulation of the resonator frequency can increase dramatically the excitation probability. Remarkabl…