Narrow Results

We investigate the influence of superposition of coherent states of light on population inversion and the evolution of the field entropy for two-level atoms in the framework of the Jaynes–Cummings model. We compare the behavior of the system in the case of having a coherent superposition state and a statistical mixture of coherent states as an initial field. Our results show that the superposition of coherent states plays an important role in the evolution of the field entropy in the intensity-dependent Jaynes–Cummings model (JCM).

In this paper we will study the statistical properties of a generalized superposition of two displaced number states of the form, with a phase difference of φ between them. A particular case of this state is obtained when we consider n₁=n₂=n and α₁=-α₂=α, which we will call even and odd displaced number state. It will be shown that they are the generalization of the even and odd coherent states. The generation of this states, based on the dispersive interaction with a two-level atom, will also be discussed.

We extend the approach in Ref. 5 [Y.-X. Liu, L. F. Wei and F. Nori, Phys. Rev. A71 (2005) 063820] for preparing superposition states of a cavity field interacting with a superconducting charge qubit. We study effects of the nonlinearity on the creation of such states. We show that the main contribution of nonlinear effects is to shorten the time necessary to build the superposition.

The superposition of pure quantum states explicitly expressed in terms of a nonlinear addition rule of state density operators is reviewed. The probability representation of density matrices of qudit states is used to formulate the interference of the states as a combination of the probability distributions describing pure states. The formalism of quantizer–dequantizer operators is developed. Examples of spin-1/2 states and f-oscillator systems are considered.

There are many routing problems belong to NP type, traditional methods will lose efficiency by ordinary because of large computation. So, in order to reduce the communication complexity, a high-speed and efficient algorithm using quantum superposition states technology has been proposed which can be used in routing choice. In this paper, we reported on the latest routing technology and constructed a general mathematical model of quantum routing algorithm according to the principle of quantum superposition states. Simulating results show that the routing through the algorithm gains an advantage over conventional algorithm. Furthermore, it has stronger practicality and robustness.