Conservation of Gaussian distributions of coherent states

Jean-Pierre Antoine, Bagarello, Fabio, Jean‐Pierre Gazeau

John C. Webber

A certain general P-distribution, which corresponds to a Gaussian distribution as a special case, is found to be conserved, with respect to time, for that general class of Hamiltonians which leave coherent states coherent.

Heng Wang, Yaodi Pi, Wei Huang +3 more

In this paper, a novel experimental preparation scheme of Gaussian modulated coherent state (GMCS) in continuous variable quantum key distribution (CVQKD) system is proposed based on dual-drive Mach-Zehnder modulator (DDMZM). The experimental implementation of the proposed GMCS preparation scheme only depends on a DDMZM instead of an AM and a PM in conventional CVQKD, which simplifies the experimental setup and reduces the costs of the CVQKD system. Moreover, the sum-difference signals of the Rayleigh distribution and uniform distribution are applied on two parallel electrodes of the DDMZM, respectively, getting rid of the accurate time-delay alignment between the AM and the PM in conventional Gaussian modulation scheme. Besides, the measurement method of the prepared GMCS is experimentally demonstrated based on heterodyne detection, and both quadrature (X and P) are simultaneously measured to verify the proposed GMCS preparation scheme.

G. M. D’Ariano, M. Vadacchino, Mario Rasetti

Thomas Alexander Meyer

We present a generalized account of how one might achieve energy conservation violation with quantum coherence effects. The general setup involves a violation of energy conservation by means of a change to the preparation of a coherent quantum mechanical effect which causes a change to the probability distribution of the measurable statistics of an observable. We also present a simple theoretical account of why there is a violation of conservation occurring in this setup.

V. V. Dodonov, E.V. Kurmyshev, Vladimir I. Man’ko