Squeezed Coherent States

M. Satyanarayana

Willi-Hans Steeb

Koushik Mandal, Pooja Jethwani, Satyanarayana, M. Venkata

Coherent signal containing squeezed noise in a mixed state of radiation field is considered here as a non-Gaussian mixture of a coherent state density operator and a squeezed state density operator, as opposed to the usual well known squeezed coherent state. Both these states are `quantum' noise-included signal states. Effects of these two distinct ways of adding squeezing to a coherent state are compared and contrasted. The main objective of this work is to study the mixed state version of the Jaynes-Cummings model in the context of a two-level atom interacting with a mixed field state of a squeezed vacuum and a coherent state. The pure squeezed coherent state (PSCS) and the mixed squeezed coherent state (MSCS) are used as the states of the radiation field. The photon-counting distribution (PCD), the atomic inversion and the entanglement dynamics of atom-field interaction for both the radiation fields are investigated and compared with each other. We observe that depending on the state of the field, squeezing has very different effects on coherent photons. Mild squeezing on the coherent photons strongly localizes the PCD for PSCS; however, for MSCS there is no such localization observed - instead squeezing manifests for MSCS as oscillations in the PCD. The effects of squeezing on the atomic inversion and the entanglement dynamics for MSCS are contrasting in comparison with the corresponding quantities associated with PSCS. It is well known in the literature that for PSCS, increasing the squeezing increases the well-known ringing revivals in the atomic inversion, and also increases irregularity in the entanglement dynamics. However, increasing the squeezing in MSCS very significantly alters the collapse-revival pattern in the atomic inversion and the entanglement dynamics of the Jaynes-Cummings model.

V. Chithiika Ruby, S Karthiga, Murugaian Senthilvelan

We explore squeezed coherent states of a three-dimensional generalized isotonic oscillator whose radial part is the newly introduced generalized isotonic oscillator whose bound state solutions have been shown to admit the recently discovered X 1 -Laguerre polynomials. We construct a complete set of squeezed coherent states of this oscillator by exploring the squeezed coherent states of the radial part and combining the latter with the squeezed coherent states of the angular part. We also prove that the three-mode squeezed coherent states resolve the identity operator. We evaluate Mandel’s Q -parameter of the obtained states and demonstrate that these states exhibit sub-Possionian and super-Possionian photon statistics. Furthermore, we illustrate the squeezing properties of these states, both in the radial and angular parts, by choosing appropriate observables in the respective parts. We also evaluate the Wigner function of these three-mode squeezed coherent states and demonstrate the squeezing property explicitly.

Baoquan Wang

We study the position and momentum entropic squeezing for squeezed coherent states in this paper.The relations between the two entropic squeezings and the two quadrature components squeezings are also discssed.It is shown there is a one-to-one correspondence between the two entropic squeezings and the two quadrature components squeezings of squeezed coherent states.