Classical and Quantum Analysis of Phase-Insensitive Systems

D.I Lalović, Dragomir M Davidović, A.R. Tančić

Søren M. M. Friis, Karsten K. Rottwitt, Colin J. McKinstrie

The noise properties of both phase-sensitive and phase-insensitive saturated parametric amplifiers are studied using a semi-classical approach. Vacuum fluctuations as well as spontaneous Raman scattering are included in the analysis.

Yee Kin Tsui

Weiqi Liu, Minghui Zhang, Jin Qi +1 more

The simultaneous classical and continuous variable quantum communication can allow classical communication and continuous variable quantum key distribution with a local local oscillator (LLO CVQKD) to be implemented simultaneously using the same communication architecture. Such scheme enables LLO CVQKD to be integrated with classical communication at the minimum cost, but the existence of reference pulses will bring security loopholes to the simultaneous communication system, allowing eavesdroppers to launch attacks. In this paper, we analyze and simulate the performance of the system by introducing the trusted noise model under the phase reference pulse intensity attack, where Eve can hide her attack by manipulating the intensity of the reference pulse using a phase insensitive amplifier. A reconstructed noise model is proposed to solve this problem. Moreover, we show that the reconstructed noise model can strengthen the security of the practical simultaneous communication system.

Mathematisch-Naturwissenschaftlich-Technischen Fakultät

Bertrand Georgeot, Dima L. Shepelyansky

We show that certain computational algorithms can be simulated on a quantum computer with exponential efficiency and be insensitive to phase errors. Our explicit algorithm simulates accurately the classical chaotic dynamics for exponentially many orbits even when the quantum fidelity drops to zero. Such phase-insensitive algorithms open new possibilities for computation on realistic quantum computers.