Eur. Phys. J. B (2013) 86: 291
https://doi.org/10.1140/epjb/e2013-40330-x

Regular Article

Symmetric excitation and de-excitation of a cavity QED system

¹ Science Institute, University of Iceland, Dunhaga 3, 107 Reykjavik, Iceland
² Reykjavik University, School of Science and Engineering, Menntavegur 1, 101 Reykjavik, Iceland
³ Department of Mechanical Engineering, National United University, 1, Lienda, 36003 Miaoli, Taiwan
⁴ Department of Physics and Center for Theoretical Sciences, National Taiwan University, 10617 Taipei, Taiwan
⁵ Center for Quantum Science and Engineering, National Taiwan University, 10617 Taipei, Taiwan

^a e-mail: vidar@hi.is

Received: 9 April 2013
Received in final form: 8 May 2013
Published online: 24 June 2013

Abstract

We calculate the time evolution of a cavity-QED system subject to a time dependent sinusoidal drive. The drive is modulated by an envelope function with the shape of a pulse. The system consists of electrons embedded in a semiconductor nanostructure which is coupled to a single mode quantized electromagnetic field. The electron-electron as well as photon-electron interaction is treated exactly using “exact numerical diagonalization” and the time evolution is calculated by numerically solving the equation of motion for the system’s density matrix. We find that the drive causes symmetric excitation and de-excitation where the system climbs up the Jaynes-Cummings ladder and descends back down symmetrically into its original state. This effect is known at low electron-photon coupling strengths but our main finding is how robust the effect is even at ultra-strong coupling strength where the JC-model does not give qualitatively correct results. We investigate the robustness of this symmetric behavior with respect to the drive de-tuning and pulse duration.