We explore the equivalence between paraxial optical beam propagation and the dynamics of a 2D quantum harmonic oscillator. We demonstrate simulation of time evolution for coherent, squeezed, and Schrödinger cat states with superposed Hermite-Gaussian modes.
Different families of states, which are solutions of the time-dependent free Schrödinger equation, are imported from the harmonic oscillator using the quantum Arnold transformation introduced in Aldaya et al (2011 J. Phys. A: Math. Theor. 44 065302). Among them, infinite series of states are given that are normalizable, expand the whole space of solutions, are spatially multi-localized and are eigenstates of a suitably defined number operator. Associated with these states new sets of coherent and squeezed states for the free particle are defined representing traveling, squeezed, multi-localized wave packets. These states are also constructed in higher dimensions, leading to the quantum mechanical version of the Hermite–Gauss and Laguerre–Gauss states of paraxial wave optics. Some applications of these new families of states and procedures to experimentally realize and manipulate them are outlined.
There has been a lot of interest recently in what are referred to as Schrodinger cat states. No precise formulation of the concepts of Schrodinger cat states and classical distinguishability appears to exist. This paper aims to explore these concepts. A number of illustrative examples are presented, including a perturbed harmonic oscillator admitting coherent states with time-dependent amplitude modulation. One can convert the results on harmonic oscillators to single-mode optical systems in the standard manner. It would be interesting to see an experimental realization of these amplitude-modulated coherent states.