Optical switching of electron transport in a waveguide-QED system

TL;DR

This paper investigates how photon energy and polarization influence electron transport in a waveguide-QED system, demonstrating photon-induced charge switching and potential quantum bit applications.

Contribution

It reveals the role of photon energy and polarization in controlling electron switching, introducing a method for quantum logic operations in waveguide systems.

Findings

Charge splits between waveguides in off-resonant fields, acting as a √NOT gate.

Total charge transfer occurs in on-resonant fields via photon replica states.

Photon polarization effectively controls charge motion.

Abstract

Electron switching in waveguides coupled to a photon cavity is found to be strongly influenced by the photon energy and polarization. Therefore, the charge dynamics in the system is investigated in two different regimes, for off- and on-resonant photon fields. In the off-resonant photon field, the photon energy is smaller than the energy spacing between the first two lowest subbands of the waveguide system, the charge splits between the waveguides implementing a $\sqrt{\rm NOT}$-quantum logic gate action. In the on-resonant photon field, the charge is totally switched from one waveguide to the other due to the appearance of photon replica states of the first subband in the second subband region instigating a quantum-NOT transition.In addition, the importance of the photon polarization to control the charge motion in the waveguide system is demonstrated.The idea of charge switching in electronic circuits may serve to built quantum bits.