The entanglement generation in a system of two nonlinear quantum oscillators

The creation and manipulation of quantum states are essential in developing quantum information theory and its applications. Such states can be applied in quantum communication, cryptography, and quantum computing. The states, defined in a finite-dimensional Hilbert space (truncated states), are relevant in this context. The physical systems in which finite-dimensional states can be generated, and the system's evolution can, thus, be limited to a certain number of n-photon states, are called quantum scissors [1]. For the cases of linear and nonlinear systems, we refer to them as linear and nonlinear quantum scissors, respectively.

In this communication, we consider a system consisting of two identical nonlinear Kerr-type quantum oscillators excited by a series of ultra-short pulses. The oscillators are coupled to each other, and the interaction between them is of the linear type. We discuss how the excitation influences the system's generation of strongly entangled states. In addition, we demonstrate that the effectiveness of creating maximally or almost maximally entangled states depends strongly on the applied excitation scheme and on the time between two subsequent pulses. In particular, we investigate how entanglement production depends on the frequencies of the excitations and on the fact that both subsystems are excited simultaneously or not [2,3].

1. W. Leoński, A. Kowalewska-Kudłaszyk, Progress in Optics, Ed. E. Wolf, 56 (2011) 131.
2. J. K. Kalaga, A. Kowalewska-Kudłaszyk, M. W. Jarosik, R. Szczęśniak, W. Leoński, Nonlinear Dynamics, 97 (2019), 1619.
3. J. K. Kalaga, A. Kowalewska-Kudłaszyk, J. Opt. Soc. Am. B, 36 (2019), 2140.