Entropy squeezing for three-level atom interacting with a single-mode field*

Abstract

The entropy squeezing for a three-level atom interacting with a single-model field is studied. A general definition of entropy squeezing for three-level atom is given according to entropic uncertainty relation of three-level system, and the calculation formalism of entropy is derived for a cascade three-level atom. By using numerical calculation, the entropy squeezing properties of a cascade three-level atom are examined. Our results show that, three-level atom can generate obvious entropy squeezing effect via choosing appropriate superposition state of three-level atom. Our results are meaningful for preparing three-level system information resources with ultra-low quantum noise.

Entropy squeezing for a V-type three-level atom interacting with a single-mode field and passing through the amplitude damping channel with weak measurement*

“…Before analyzing the entropy squeezing properties of the atom in our systems, we firstly review the general definition of the entropy squeezing of a three-level atom given by Ref. [14]. As is well known, a three-level atom can be described by dipole operators S α (α = x, y, z), which satisfy the commutation relationship [S x , S y ] = iS z .…”

“…In other words, when the atom is prepared in this optimal entropy squeezing state initially, the field can keep the atom in this optimal entropy squeezing state, which is a great advantage over the Ξ-type three-level atom in Ref. [14]. 3.2.…”

“…Via the non-Hermitian operation, Wang et al [13] have provided a scheme for generating sustained optimal entropy squeezing of a two-level atom. However, all of the researches mentioned above are aimed at twolevel atom while there is little attention devoted to the entropy squeezing of three-level atom until Liu et al [14] made a general definition of entropy squeezing for a Ξ-type three-level atom recently.…”

“…[20] Motivated by the above-mentioned advantages and considering one of the author in Refs. [14] has present the entropy squeezing of the Ξ-type atom only, we focus our attention on the squeezing properties of a V-type threelevel atom in this paper. Firstly, we conduct a review of the definition of the entropy squeezing of three-level atom.…”

Steady and optimal entropy squeezing for three types of moving three-level atoms coupled with a single-mode coherent field*

“…[19][20][21] For example, it provides higher channel ca-pacities, more secure cryptography as well as superior quantum gates. Liu [22] proposed the entropy squeezing of a threelevel atom interacting with a single-mode field by using the quantum information entropy theory, but no one studied the entropy squeezing properties of a moving three-level atom. In this paper, we investigate the entropy squeezing properties of three types of moving three-level atoms coupled with a singlemode coherent field, and explore the possibility of achieving steady and optimal entropy squeezing of three-level atom by using atomic motion and without additional any complex techniques.…”