Higher dimensional quantum communication in a curved spacetime: an efficient simulation of the propagation of the wavefront a photon

Abstract

A photon with a modulated wavefront can produce a quantum communication channel in a larger Hilbert space. For example, higher dimensional quantum key distribution (HD-QKD) can encode information in the transverse linear momentum (LM) or orbital angular momentum (OAM) modes of a photon. This is markedly different than using the intrinsic polarization of a photon. HD-QKD has advantages for free space QKD since it can increase the communication channels tolerance to bit error rate (BER) while maintaining or increasing the channels bandwidth. We describe an efficient numerical simulation of the propagation photon with an arbitrary complex wavefront in a material with an isotropic but inhomogeneous index of refraction. We simulate the waveform propagation of an optical vortex in a volume holographic element in the paraxial approximation using an operator splitting method. We use this code to analyze an OAM volume-holographic sorter. Furthermore, there are analogue models of the evolution of a wavefront in the curved spacetime environs of the Earth that can be constructed using an optical medium with a given index of refraction. This can lead to a work-bench realization of a satellite HD-QKD system. arXiv:1812.09644v1 [gr-qc]

How gravitational fluctuations degrade the high-dimensional spatial entanglement

“…, that span an infinite-dimensional Hilbert space [3][4][5][6][7][8][9][10][11][12][13][14]. Due to the fact that information may be encoded in a high-dimensional space, light with OAM is a potential source for future quantum communications [15]. However, OAM entanglements are suffered from the adverse effects from the environment.…”