  In this paper, the higher energy levels of the transmon qubit are taken into
consideration to investigate the continuous variable entanglement generation
between the transmon qubit and the single-mode cavity. Based on the framework
of cavity quantum electrodynamics, we show the entanglement generation depends
on the the driving field intensity, coupling strength, cavity field frequency,
and qubit frequency. The numerical results show that strong entanglement can be
generated by properly tuning these parameters. It is our hope that the results
presented in this paper may lead to a better understanding of quantum
entanglement generation in cavity QED system and provide new perspectives for
further research in quantum information processing.
