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Nonclassical Properties of Superposition of Two Coherent States Shifted in Phase by 3π/2

Ahmad, Muḥammad Muḥammad, Ashfaq +2 more

Chinese Physics LettersJan 1, 20065 citations

Non-classicalities exhibited by the superposition of Schrödinger’s cat state with the vacuum of the optical field

Karunesh Kumar Mishra, Dhiraj Yadav, Gaurav K. Shukla +1 more

Abstract Superposition of two coherent states, the Schrodinger’s cat state, can exhibit different nonclassical properties having foundational applications in quantum information processing. We consider the ‘superposition of Schrodinger’s cat state with the vacuum state (SCVS)’ of the optical field. We discuss different witness of nonclassicality properties such as lower- and higher-order squeezing (viz., squeezing, Hong & Mandel’s fourth-order squeezing, amplitude-squared squeezing) and sub-Poissonian photon statistics. Further, we discuss the negativity of the Wigner function of SCVS indicating the nonclassicality of the state under investigation. We find that the vacuum state contribution in SCVS exhibits different nonclassicalities under some conditions stronger where the nonclassicalities exhibited by the state without vacuum state contribution are weaker.Abstract Superposition of two coherent states, the Schrodinger’s cat state, can exhibit different nonclassical properties having foundational applications in quantum information processing. We consider the ‘superposition of Schrodinger’s cat state with the vacuum state (SCVS)’ of the optical field. We discuss different witness of nonclassicality properties such as lower- and higher-order squeezing (viz., squeezing, Hong & Mandel’s fourth-order squeezing, amplitude-squared squeezing) and sub-Poissonian photon statistics. Further, we discuss the negativity of the Wigner function of SCVS indicating the nonclassicality of the state under investigation. We find that the vacuum state contribution in SCVS exhibits different nonclassicalities under some conditions stronger where the nonclassicalities exhibited by the state without vacuum state contribution are weaker.

Physica ScriptaJan 26, 202112 citations

Nonclassical properties of coherent states

Lars M. Johansen

arXiv:quant-ph/0309025Physics Letters AJul 22, 200453 citations

Higher-order nonclassicalities of finite dimensional coherent states: A comparative study

Nasir Alam, Amit Verma, Anirban Pathak

arXiv:1712.10135Physics Letters AApr 25, 201817 citations

Lower- versus higher-order nonclassicalities for a coherent superposed quantum state

Deepak Deepak, Arpita Chatterjee

A coherent state is defined conventionally in different ways such as a displaced vacuum state, an eigenket of an annihilation operator, or as an infinite dimensional Poissonian superposition of Fock states. In this work, we describe a superposition ( t a + r a † ) of field annihilation and creation operators acting on a continuous variable coherent state | α ⟩ and specify it by | ψ ⟩ . We analyze the lower- as well as higher-order nonclassical properties of | ψ ⟩ . The comparison is performed by using a set of nonclassicality witnesses (e.g., higher-order photon statistics, higher-order antibunching, higher-order sub-Poissonian statistics, higher-order squeezing, Agarwal–Tara parameter, Klyshko’s condition, and a relatively new concept, matrix of phase-space distribution). It is found that the higher-order criteria are much more efficient to detect the presence of nonclassicality as compared to lower-order conditions except squeezing, where the lower-order one is more competent than its higher-order counterpart.A coherent state is defined conventionally in different ways such as a displaced vacuum state, an eigenket of an annihilation operator, or as an infinite dimensional Poissonian superposition of Fock states. In this work, we describe a superposition ( t a + r a † ) of field annihilation and creation operators acting on a continuous variable coherent state | α ⟩ and specify it by | ψ ⟩ . We analyze the lower- as well as higher-order nonclassical properties of | ψ ⟩ . The comparison is performed by using a set of nonclassicality witnesses (e.g., higher-order photon statistics, higher-order antibunching, higher-order sub-Poissonian statistics, higher-order squeezing, Agarwal–Tara parameter, Klyshko’s condition, and a relatively new concept, matrix of phase-space distribution). It is found that the higher-order criteria are much more efficient to detect the presence of nonclassicality as compared to lower-order conditions except squeezing, where the lower-order one is more competent than its higher-order counterpart.

arXiv:2304.05054Journal of the Optical Society of America BSep 17, 20212 citations

One dimensional representations in quantum optics

József Janszky

As a generalization of the optical Schroedinger cats discrete and continuous sets of coherent states are considered on a circle and on a straight line in the a-plane. The interference fringes between the coherent states of the Schroedinger cats form the characteristic pattern of the nonclassical states in Wigner function picture. Continuos superpositions of coherent states on these one-dimensional manifolds can serve as an orthonormal basis for representation of any states.

16th Congress of the International Commission for Optics: Optics as a Key to High TechnologyJul 26, 19930 citations

Higher-Order Nonclassical Properties of a Shifted Symmetric Cat State and a One-Dimensional Continuous Superposition of Coherent States

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