Nonlinearity Induced Entanglement Stability in a Qubit-Oscillator System

Víctor Montenegro, Alessandro Ferraro, Sougato Bose

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10 Citations (Scopus)
222 Downloads (Pure)


We consider a system composed of a qubit interacting with a quartic (undriven) nonlinear oscillator (NLO) through a conditional displacement Hamiltonian. We show that even a modest nonlinearity can enhance and stabilize the quantum entanglement dynamically generated between the qubit and the NLO. In contrast to the linear case, in which the entanglement is known to oscillate periodically between zero and its maximal value, the nonlinearity suppresses the dynamical decay of the entanglement once it is established. While the entanglement generation is due to the conditional displacements, as noted in several works before, the suppression of its decay is related to the presence of squeezing and other complex processes induced by two- and four-phonon interactions. Finally, we solve the respective Markovian master equation, showing that the previous features are preserved also when the system is open.
Original languageEnglish
Article number 013829
Number of pages10
JournalPhysical Review A (Atomic, Molecular, and Optical Physics)
Publication statusPublished - 23 Jul 2014


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