Quasienergy operators and generalized squeezed states for systems of trapped ions

TL;DR

This paper explores the quantum dynamics of trapped ions using quasienergy operators, introduces symplectic coherent states via Lie algebra generators, and demonstrates how to engineer squeezed states of the electromagnetic field through group-theoretic methods.

Contribution

It introduces a novel group-theoretic framework for constructing quasienergy and squeezed states in trapped ion systems, linking Lie algebra generators to quantum stability and state engineering.

Findings

Quantum stability characterized by discrete quasienergy spectrum.

Construction of symplectic coherent states using Lie algebra generators.

Method to engineer squeezed electromagnetic states via ion-laser interactions.

Abstract

Collective many-body dynamics for time-dependent quantum Hamiltonian functions is investigated for a dynamical system that exhibits multiple degrees of freedom, in this case a combined (Paul and Penning) trap. Quantum stability is characterized by a discrete quasienergy spectrum, while the quasienergy states are symplectic coherent states. We introduce the generators of the Lie algebra of the symplectic group ${\cal {SL}}(2, \mathbb R)$, which we use to build the coherent states (CS) associated to the system under investigation. The trapped ion is treated as a harmonic oscillator (HO) to which we associate the quantum Hamilton function. We obtain the kinetic and potential energy operators as functions of the Lie algebra generators and supply the expressions for the classical coordinate, momentum, kinetic and potential energy, as well as the total energy. In addition, we also infer the dispersions for the coordinate and momentum, together with the asymmetry and the flatness parameter for the distribution. The system interaction with laser radiation is also examined for a system of identical two-level atoms. The Hamilton function for the Dicke model is derived. The optical system is modelled as a HO (trapped ion) that undergoes interaction with an external laser field and we use it to engineer a squeezed state of the electromagnetic (EM) field. We consider coherent and squeezed states associated to both ion dynamics and to the EM field. Such an approach enables one to build CS in a compact and smart manner by use of the group theory.