Light, matter, and quantum randomness generation: A relativistic quantum information perspective

Abstract

We study how quantum randomness generation based on unbiased measurements on a hydrogenlike atom can get compromised by the unavoidable coupling of the atom with the electromagnetic field. We improve on previous literature by analyzing the light-atom interaction in 3+1 dimensions with no single-mode or rotating-wave approximations and taking into account the non-pointlike nature of the atom, its orbital structure, and the exchanges of angular momentum between atom and field. We show that preparing the atom in the ground state in the presence of no field excitations is not universally the safest state to generate randomness. arXiv:1710.06875v2 [quant-ph]

Casimir forces and quantum friction of finite-size atoms in relativistic trajectories

“…The formalism developed here for general relativistic trajectories is easily generalizable to the electromagnetic field (with the techniques in [57][58][59]), more realistic models of macroscopic objects (See [30,49,52]) and more realistic detectors, such as multilevel atoms. In this appendix, we are going to show explicitly the evaluation of the trace of Eq.…”

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 ].…”

Quantum delocalization, gauge and quantum optics: The light-matter interaction in relativistic quantum information

“…Of course, the spread of this localization will be bounded from below by the atomic orbital wavefunctions support, but we find that it is the center of mass localization what gives the spatial extension to the atom in the dipole approximation. It is convenient to take a momentum representation for the COM degrees of freedom in (50). We note that for all COM states |Ψ com…”

“…For simplicity and also comparison with previous works, we can further assume that the time-dependent coupling is of Gaussian adiabatic nature, i.e. χ(t) = exp −(t/T ) 2 with T being the time scale of interaction (A discussion on the physicality of such a switching function for the light-matter interaction can be found in, e.g, [50]). After a lengthy but simple calculation that parallels the calculation in Appendix A of [50], using Eq.…”