We propose and study a new kind of superposition states: even- and odd-displaced squeezed states, defined as and , which are characteristic of possessing even and odd photon numbers respectively. We find that the even-displaced squeezed state may exhibit stronger squeezing than that of the ordinary squeezed state .
We study even- and odd-displaced squeezed states, which were proposed by us as 1/N e (D(z)+D(-z))S(r) mod 0) and 1/N 0 (D(z)-D(-z))S(r) mod 0). We find: (i) when z is real, the 2Nth moments in both states are larger than in the ordinary squeezed state; (ii) for the same z= mod z mod , the two states can not exhibit stronger squeezing than the squeezed state in the same order; (iii) under the condition mod z mod e -r square root 2>>1, the even (odd)-displaced squeezed state can respectively exhibit stronger (4k-2) (4k)-order (k=1,2,3,...) squeezing than the squeezed state.
Based on the quantum superposition principle,we construct a new type of superposition composed of coherent state and squeezed state |φ=N(|α+eiφ|βg);and study its squeezing effect and photon anti-bunching effect.The results show that this kind of superposition exhibits fluent quantum properties.When superposed as even/odd coherent states,the superposition exhibits some properties of both even/odd coherent states and squeezed even/odd coherent states.The even/odd coherent and coherent state can be obtained as a special case when the squeezed factor r is zero.
We mainly examine the nonclassical statistical properties of both squeezed even and Squeezed odd coherent states defined by the superposed states involving two squeezed coherent states with a phase difference n between their displacement parameters. We demonstrate that the fields in squeezed even coherent state can exhibit remarkably enhanced squeezing level and mean photon number in comparison with the input squeezed coherent state. We also point out the examples of the physical processes leading to such a superpotition.
We define and study the properties of ``squeezed quantum multiplets''. Ordinary multiplets are sets of D-orthonormal quantum states formed by superpositions of states squeezed along D equally spaced directions in quadrature space. More generally, we also discuss superpositions of ``higher-order squeezed states'', including tri-squeezed and quad-squeezed states. All these states involve superpositions of multiples of p photons. We compare states in ordinary (p=2) multiplets and higher-order ones (p>2) in the most relevant cases, showing that ordinary squeezed multiplets and higher-order ones share some important similarities, as well as some differences. Finally, we present analytical expressions for phase-space distributions (Wigner and characteristic functions) representing ordinary squeezed multiplets. We use this to show that some squeezed multiplets are highly sensitive to perturbations in all phase-space directions, making them interesting for metrological applications.
In this paper, first, we introduce special types of entangled quantum states named “entangled displaced even and odd squeezed states” by using displaced even and odd squeezed states which are constructed via the action of displacement operator on the even and odd squeezed states, respectively. Next, we present a theoretical scheme to generate the introduced entangled states. This scheme is based on the interaction between a [Formula: see text]-type three-level atom and a two-mode quantized field in the presence of two strong classical fields. In the continuation, we consider the entanglement feature of the introduced entangled states by evaluating concurrence. Moreover, we study the influence of the displacement parameter on the entanglement degree of the introduced entangled states and compare the results. It will be observed that the concurrence of the “entangled displaced odd squeezed states” has less decrement with respect to the “entangled displaced even squeezed states” by increasing the displacement parameter.