Relativistic quantum key distribution system with one-way quantum communication

Abstract

Unambiguous state discrimination (USD) is one of the major obstacles for practical quantum key distribution (QKD). Often overlooked, it allows efficient eavesdropping in majority of practical systems, provided the overall channel loss is above a certain threshold. Thus, to remain secure all such systems must not only monitor the actual loss, but also possess a comprehensive information on the safe ‘loss vs. BER’ levels, which is often well beyond currently known security analyses. The more advanced the protocol the tougher it becomes to find and prove corresponding bounds. To get out of this vicious circle and solve the problem outright, we demonstrate a so called relativistic QKD system, which uses causality to become inherently immune to USD-based attacks. The system proves to be practical in metropolitan line-of-sight arrangements. At the same time it has a very basic structure that allows for a straightforward and comprehensive security analysis.

A Physically-Motivated Quantisation of the Electromagnetic Field on Curved Spacetimes

“…Finally, instead of depending on , the electric and magnetic field observables now depend on , i.e., they depend not only on the position but also on the amount of time the observer has been accelerating in space and on their acceleration. Most importantly, Equation (76) can now be used as the starting point for further investigations into the quantum optics of an accelerating observer [ 5 , 36 , 46 ], and is expected to find immediate applications in relativistic quantum information [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 69 ].…”

“…Recently, relativistic quantum information has received a lot of attention in the literature. Pioneering experiments verify the possibility of quantum communication channels between Earth’s surface and space [ 13 ] and have transmitted photons between the Earth and low-orbit satellites [ 14 ], while quantum information protocols are beginning to extend their scope towards the relativistic arena [ 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. The effects of gravity on satellite-based quantum communication schemes, entanglement experiments and quantum teleportation have already been shown to produce potentially observable effects [ 22 , 23 , 24 , 25 ].…”

Higher-rate relativistic quantum key distribution

“…In this section, we introduce a relativistic quantum key distribution protocol, which could be regarded as a modified version of the scheme in Ref. 42 or that of Ref. 43 .…”

“…As in Refs. 42 , 43 , the instant is regarded as the beginning of the protocol. After passing the beam splitter, the quantum system jumps over into a superpositional state of the interferometer.…”

“…It is based on putting relativistic limitations to an eavesdropper: “... They allow to force Eve make decisions about her actions before she can actually measure the state in the line, thus breaking her only winning strategy due to causality” 42 . In other words, the relativistic model does not give Eve any chance to launch an attack in due time so that she cannot gather information about the transferred data in an unhindered manner.…”