Journal of Optics B Quantum and Semiclassical Optics

On Schrödinger cat states and classical distinguishability

K. Kong Wan, R Green, Colin Trueman

Published Apr 1, 2000• 0 citations

Abstract

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.

DOI: 10.1088/1464-4266/2/2/318

Related papers

Generation of Glauber Coherent State Superpositions via Unitary Transformations

ANTONINO MESSINA, Benedetto Militello, Anna Napoli

Since their introduction by Glauber in 1963 [1], coherent states have been deeply studied [2] due to the fact that, in some sense, the statistical properties related to the first momenta of their Fock distribution exhibit features interpretable in the realm of classical probability theory. Of course the quantum nature of a coherent state, and ultimately the granularity of the energy of a quantum harmonic oscillator, becomes more and more evident when higher momenta of the Fock distribution are considered. It is of relevance that coherent states of both a mechanical quantum oscillator or a quantized mode of an electromagnetic resonator may be currently proposed in accordance with well-defined protocols. Even more interesting is the fact that they provide the effective possibility of realizing interesting experiments able to bring to the light peculiarities of quantum mechanics. In particular, the very famous gedanken Schrodinger Cat State (SCS) experiment [3] consisting in entangling a microscopic quantum object (an atom) with a macroscopic one (a cat) has been realized. No unfortunate feline has been tortured! Trapped ions have been indeed exploited. In fact, such systems provide the possibility of testing fundamental quantum physics aspects giving at experimentalist’s disposal compound quantum systems consisting of a few-level atomic part and a tri-dimensional harmonic oscillator describing the center of mass motion of an ion confined into a Paul trap. Suitably acting upon the system with Raman lasers it is possible to engineer the Schrodinger Cat-like state [4, 5]

Jan 1, 20042 citations

Classical Behavior of a Macroscopic Schrödinger Cat

Carlo Presilla A

We study the dynamics of classical and quantum systems linearly interacting with a classical environment represented by an infinite set of harmonic oscillators. The environment induces a dynamical localization of the quantum state into a generalized coherent state for which the ħ → 0 limit always exists and reproduces the classical motion. We describe the consequences of this localization on the behavior of a macroscopic system by considering the example of a Schrödinger cat.

Kluwer Academic Publishers eBooksDec 19, 20050 citations

Quantum superpositions and Schrödinger cat states in quantum optics

Christopher C. Gerry, P. L. Knight

We describe the properties of a quantum system prepared in superpositions of classically distinguishable states. These states, often called Schrödinger cat states, are of great interest at present. We discuss how they may be realized in quantum optics using nonlinear interactions and cavity quantum electrodynamics. We first describe the quantum properties of field states in a cavity, and demonstrate the interference properties which characterize superposition states and discuss how fragile they are in dissipative environments. Finally, we review current experimental approaches which may realize these states.

American Journal of PhysicsOct 1, 1997152 citations

Generation and Detection of Linear Superpositions of Classically Distinguishable States of a Radiation Mode

David Vitali, P. Tombesi

A full comprehension of the fuzzy boundary between the classical and the quantum world is still lacking. A deeper understanding of the problem can be obtained form the study of the so-called "Schrödinger cat states", i.e. the paradoxical states arising when the superposition principle of quantum mechanics is extended to the macroscopic world. Quantum optics is, up to now, the most studied field for the experimental realization of these states. A survey of all the proposals made for generating and detecting linear superpositions of classically distinguishable states in quantum optical systems is presented. Then, one of the most recent proposals [P. Tombesi and D. Vitali, Phys. Rev. Lett.77, 411 (1996)] is presented in detail and its experimental feasibility discussed.

International Journal of Modern Physics BJul 20, 19973 citations

Two-mode photon added Schrödinger cat states: nonclassicality and entanglement

S. Nibedita Swain, Yashovardhan Jha, Prasanta Kumar Panigrahi

The concept of a photon added two-mode Schrödinger cat state in which both modes are independent is introduced, and their nonclassical properties and entanglement are studied. The introduced states emerge as eigenstates of f 1 f 2 a 1 a 2 , where f 1 , f 2 are nonlinear functions of the number operator, and a 1 , a 2 are annihilation operators. We study the evolution of these states under canonical transformation using the parity operator for the case of standard coherent states of the harmonic oscillator. The nonclassical properties of these states are evaluated especially by considering sub-Poissonian photon statistics and photon number distribution. Interestingly, the addition of photons leads to shifting the region in which photon number distribution shows oscillatory behavior. In addition, the entanglement of introduced states is quantitatively analyzed using concurrence. We observe that the state approaches maximum entanglement more rapidly after the addition of photons.

arXiv:2202.00518Journal of the Optical Society of America BSep 27, 20225 citations

Sensitive Schrödinger Cat States

Shahab Ramezanpour

Strong laser-atom interactions can produce highly non-classical states of light by using the process of high-harmonic generation in atoms. When the high-harmonic generation is present, the quantum state of the fundamental mode following the interaction is known as the Schrödinger cat state, which is a superposition of the laser’s initial coherent state and the coherent state with a smaller amplitude that results from its interaction with atoms. Here, we demonstrate that new light states with significantly different Wigner function distributions can be produced by combining two separate Schrödinger cat states. Through the engineering of Schrödinger cat states’ parameters, we are able to produce Wigner functions that exhibit high sensitivity in relation to the system parameter. Our research paves the way for the creation of non-classical light by superposing Schrödinger cat states with application in such as quantum sensing.

Nov 20, 20230 citations