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arXiv · 1306.4275

Quantum signalling in cavity QED

Robert H. Jonsson·Eduardo Martin-Martinez·Achim Kempf
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Abstract

We consider quantum signalling between two-level quantum systems in a cavity, in the pertubative regime of the earliest possible arrival times of the signal. We present two main results: First we find that, perhaps surprisingly, the analogue of amplitude modulated signalling (Alice using her energy eigenstates |g>, |e>, as in the Fermi problem) is generally sub-optimal for communication. Namely, e.g., phase modulated signalling (Alice using, e.g., |+>,|e>-states) overcomes the quantum noise already at a lower order in perturbation theory. Second, we study the effect of mode truncations that are commonly used in cavity QED on the modelling of the communication between two-level atoms. We show that, on general grounds, namely for causality to be preserved, the UV cutoff must scale at least polynomially with the desired accuracy of the predictions.

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Robert H. Jonsson, Eduardo Martin-Martinez, Achim Kempf. 2014-02-19. Quantum signalling in cavity QED. https://doi.org/10.1103/physreva.89.022330

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