Abstract
We present a paradigm in the field of cavity QED by bringing out remarkable features associated with the avoided crossing of the dressed-state levels of the Jaynes-Cummings model. We demonstrate how the parametric couplings, realized by a second order nonlinearity in the cavity, can turn the crossing of dressed states into avoided crossings. We show how one can generate coherence between the avoided crossing of dressed states. Such coherences result, for example, in quantum beats in the excitation probability of the qubit. The quality of quantum beats can be considerably improved by adiabatically turning on the parametric interaction. We show how these avoided crossings can be used to generate superpositions of even or odd Fock states with the remarkable property of equal weights for the states in superposition. The fidelity of generation is more than 95%. In addition, we show strong entanglement between the cavity field and the qubit with the concurrence parameter exceeding 90%.
Highlights
Avoided level crossing [1,2] is the phenomenon where two energy levels cannot be pushed through each other and has been an important branch of physics
We have brought out many important consequences of the JC model when the cavity is incorporated by a parametric nonlinearity
The parametric nonlinearity produces avoided crossings between the dressed states of the JC model which otherwise cross at certain values of the detuning and the coupling of the qubit to the cavity field
Summary
Avoided level crossing [1,2] is the phenomenon where two energy levels cannot be pushed through each other and has been an important branch of physics. We present a paradigm in the field of cavity QED by bringing out effects associated with the avoided crossing of the dressed-state levels of the Jaynes-Cummings (JC) model. We demonstrate how the parametric couplings can turn the crossing of dressed states into avoided crossings. Such coherences can be monitored via the quantum beats in the excitation probability of the qubit These avoided crossings can be used to generate superpositions of even or odd Fock states with the remarkable property. In the presence of the perturbation, i.e., the pump field, avoided level crossing between dressed states will occur, yielding quantum beats, entanglement, and the superposition state of even or odd Fock states. This example demonstrates in a simple way how the parametric drive can produce avoided crossing of the dressed states |+, 0 and |−, 2. Crossings involving dressed states |+, 0 and |−, 2 (|+, 0 and |−, 4 )
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
