Superluminal processes in quantum electrodynamics

B. A. Veklenko

Without using the perturbation theory, the article demonstrates a possibility of superluminal information-carrying signals in standard quantum electrodynamics using the example of scattering of quantum electromagnetic field by an excited atom.

B. A. Veklenko

Using as an example the Fermi problem dealing with nonstationary transformation of optical excitation from one atom to another the reason of superluminal signals appearance in quantum electrodynamics is clearing.It is shown that the calculation using the conventional methods in Heisenberg and Schrödinger representations in nonstationary problems lead to different results.The Schrödinger representation predicts the existents of specified quantum superluminal signals.In Heisenberg representation the superluminal signals are absent.The reason of non-identity of representations is close connected with using of the adiabatic hypothesis.

Jiahua Li, Rong Yu, Jiuyang Liu +2 more

We study the probe-field transmission in cavity quantum electrodynamics (cavity-QED) systems with a partially transmitting element (PTE), where the PTE is used to control and tune the amplitude of the weak probe field propagating along a single waveguide channel in the structure. We derive analytic formulas utilized to determine the transmission coefficient of the probe field within the framework of quantum optics. Using experimentally accessible parameters, it is clearly shown that the asymmetric Fano-resonance line shape can be formed and manipulated by means of the added PTE. Furthermore, we reveal that there exists superluminal light with large intensity transmission in the transport spectrum of the waveguide-coupled cavity-QED system. This superluminal-light propagation effect, which exhibits the anomalous phase shift and is characterized by the negative group delay, can be enhanced by properly choosing the system parameters. The obtained results may be used for designing switching, modulation, and sensing for nanophotonic applications and ultrafast on-chip signal processing in telecom applications.

Andrey G. Grozin