Field purification in the intensity-dependent Jaynes-Cummings model

Abstract

We have found that, in the intensity-dependent Jaynes-Cummings model, a field initially prepared in a statistical mixture of two coherent states, |α and | − α , evolves toward a pure state. We have also shown that an even-coherent state turns periodically a into rotated odd-coherent state during the evolution.

Non-conditioned generation of Schrödinger cat states in a cavity

“…This is the case, e.g. for the intensitydependent JCM [14,32]. We show that it also may be the case for the JCM with a Kerr-like medium: from the second order derivative of the Rabi frequency,…”

“…We have found that, the JCM with a nonlinear Kerr-like medium, under suitable combinations of the atom-field detuning δ and the nonlinear parameter χ (3) and for an initial field prepared either in a coherent state or in a statistical mixture of two coherent states, makes possible a Schrödinger cat state generation with higher fidelity than the JCM without a nonlinear medium. We would like to remark that in the ordinary JCM, the initial field in a coherent state evolves to a state close to a Schrödinger cat state at a specific time, as reported in [13], and if we start with a statistical mixture of two coherent states, the field basically remains in a mixed state [14,20]. The possibility of generating superpositions of coherent states in the JCM with a nonlinear Kerr-like medium with an atom-field detuning has not been yet addressed in the literature.…”

“…Several schemes using coherent states have been proposed [5,6,7,8,9], and a few experimental realizations have been already accomplished in cavity QED as well as in trapped ions systems [10,11,12]. In cavity QED models, states close to those superpositions arise at specific times, for the cavity field initially in a coherent state [13] or even in a statistical mixture of two coherent states [14]. Propositions such as the Yurke-Stoler generation scheme [5], and those based on quantum non-demolition processes (QND), depend on very large values of Kerr nonlinearities, which is probably the main obstacle for their implementation [10].…”

Interplay of information quantifiers and the modified Jaynes-Cummings model

“…We review below the main details for the treatment of a two-level atom interacting with a single-mode of the cavity field [5]. The Hamiltonian, in the rotating wave approximation, can be written as [5] …”

“…Because of the commensurability of the Rabi frequencies arising from the model's couplings, periodic revivals emerge, absent in the original JCM, with a time-dependent state-vector that is periodic itself. As a consequence, any expectation value will share such feature, which leads to an enhancement of certain effects that would otherwise be ignored by JCM-practitioners [4,5]. We wish here to revisit the Buck-Sukumar model using information-theory tools (ITT) so as to be in a position to, hopefully, display interesting details of the concomitant dynamics.…”