Multi-quantum States Research Articles

Study on unified expression of event occurrence flexible logic based on superposition quantum states

To determine the multi logical relationship in the process of cause event leading to result event, a unified expression of flexible logic of event occurrence based on the superposition of multi quantum states is proposed. According to the premise that the logical relationship between any numbers of events can be simplified to the logical relationship between the two events, 20 kinds of flexible logical relationships are studied, and 16 of them are selected to establish the unified expression of flexible logic of event occurrence. By studying those 16 kinds of logical relationships, 8 kinds of logical relationships without obvious correlation are further determined, and finally the unified expression of event occurrence flexible logic of superposition of three quantum states is formed. The result shows that the expression can express 8 kinds of superposition states of logical relationships at the same time, and the different logical forms in the probability of occurrence of result events can be obtained. Finally, the characteristics of the expression and the problems that may be encountered in the process of solving are analyzed. And through the example analysis, the usage process and function of the present method were explained. It can be used to express the logical relationship between the cause event and the result event in the system fault evolution and determine the probability of fault occurrence.

Understanding of the C-H stretch region of infra-red spectroscopy: an analysis of the final state wavefunctions.

The nature of the wavefunctions associated with the final states in the CH stretching region of several medium sized molecules is analysed. The number of optically bright transitions is much larger than the number of CH oscillators present in the molecule, and they are spread over a range of about 300 cm-1. Several of them are clustered together within about 5 cm-1 with near equal intensities. The final states of all these transitions are superpositions of multiple zeroth order states. In almost all of such superpositions, no single zeroth order state has more than 50% weight. Several multiquantum states, with three to four quanta of excitation dominate the final states, with the CH chromophore contributing only a small weightage. Thus the band structure of the CH stretch region is due to several optically bright transitions whose final states are superpositions of low frequency multiquantum states with the CH chromophore contributing only a small weight to make them spectroscopically active.

Stochastic scattering theory for excitation-induced dephasing: Time-dependent nonlinear coherent exciton lineshapes.

We develop a stochastic theory that treats time-dependent exciton-exciton s-wave scattering and that accounts for dynamic Coulomb screening, which we describe within a mean-field limit. With this theory, we model excitation-induced dephasing effects on time-resolved two-dimensional coherent optical lineshapes and we identify a number of features that can be attributed to the many-body dynamics occurring in the background of the exciton, including dynamic line narrowing, mixing of real and imaginary spectral components, and multi-quantum states. We test the model by means of multidimensional coherent spectroscopy on a two-dimensional metal-halide semiconductor that hosts tightly bound excitons and biexcitons that feature strong polaronic character. We find that the exciton nonlinear coherent lineshape reflects many-body correlations that give rise to excitation-induced dephasing. Furthermore, we observe that the exciton lineshape evolves with the population time over time windows in which the population itself is static in a manner that reveals the evolution of the multi-exciton many-body couplings. Specifically, the dephasing dynamics slow down with time, at a rate that is governed by the strength of exciton many-body interactions and on the dynamic Coulomb screening potential. The real part of the coherent optical lineshape displays strong dispersive character at zero time, which transforms to an absorptive lineshape on the dissipation timescale of excitation-induced dephasing effects, while the imaginary part displays converse behavior. Our microscopic theoretical approach is sufficiently flexible to allow for a wide exploration of how system-bath dynamics contribute to linear and non-linear time-resolved spectral behavior.

Quantum states sharing in the relay system with teleportation of non-maximally entanglement

A novel scheme for multi-quantum-state sharing is proposed based on the relay system with teleportation in the non-maximally-entangled channel in order to improve the efficiency of secure distribution of quantum states for communications. Multi quantum states are encoded as quantum packets and teleported from the source to the destination with assistance of the relay. It demonstrates that secure multi quantum states sharing can be achieved and meanwhile the range of quantum communication can be increased and approximately doubled. It provides a valuable application prospect in long distance reliable communications and a wide application to quantum networks.

Multi-quantum states quantum-inspired evolutionary algorithm for layout optimization problem and its application

To solve the prematurity of evolutionary algorithm on the equilibrium constrained circles packing problem,the Multi-Quantum States Quantum-Inspired Evolutionary Algorithm(MQSQIEA) proposed in this paper was beneficial to keeping the population diversity,which combined the heuristics based on the order-based positioning technique.The layout sequence was optimized efficiently by MQSQIEA.The solving speed was improved by the multi-quantum states coding and the convergence criterion based on the average convergence probability.The observation method based on the taboo strategy and heuristic information was introduced to obtain the n-ary solution with different integers and ensure the priority to place circles with large mass and long radius.The dynamic quantum evolutionary strategy was applied to guide the population to evolve towards the best individual.The positioning probability function introduced to the positioning rule was employed to improve the solution quality.The numerical experimental results show that the proposed method can effectively solve the circular packing problem with equilibrium constraints.

Extended hydrodynamic approach to quantum-classical nonequilibrium evolution. II. Application to nonpolar solvation

The mixed quantum-classical formulation derived in our companion paper [D. Bousquet, K. H. Hughes, D. Micha, and I. Burghardt, J. Chem. Phys. 134, 064116 (2011)], which is based upon a hydrodynamic representation of the classical sector, is applied to nonequilibrium nonpolar solvation dynamics as exemplified by the solvation of the electronically excited NO molecule in a rare gas environment. Derived from a partition of the Hamiltonian into a primary (quantum) part and a secondary (classical) part the hydrodynamic equations are formulated for multi-quantum states and result in explicit equations of motion for populations and coherences. The hierarchy of hydrodynamic equations is truncated by the following approximate closure schemes: Gauss-Hermite closure, dynamical density functional theory approximation, and a generalized Maxwellian closure. A comparison of the dynamics using these three closure methods showed that the suitability of a particular closure scheme was dependent on the initial conditions and the nonequilibrium character of the dynamics.

Multiquantum states derived from Davydov's ansatz: II. An exact special case solution for the Su-Schrieffer-Heeger Hamiltonian and its relation to the state

We present the derivation of an exact special case solution (for a classical lattice) for the Su-Schrieffer-Heeger model for the calculation of soliton dynamics in trans-polyacetylene. Our solution is exact, in the sense that the ansatz state yields an exact solution provided that the equations of motion for its parameters are obeyed. However, these equations can be solved only numerically (in principle to any desired accuracy), not analytically. The model is applied to time simulations of neutral solitons as a function of temperature. We find agreement of the results of our time simulations with experimental data on the mobility of neutral solitons in the system. Comparative calculations using the completely adiabatic model indicate that the results of this model are at variance both with experiment and with those of our model. A simple consideration of the potential barriers for soliton displacement leads to an overestimation of the soliton mobility for low temperatures and an underestimation for higher ones. In an appendix we discuss in some detail the relationship of this exact solution with the state ansatz as presented in our previous paper. We find that the ansatz state and the exact solution yield identical results for lattice momenta, displacements and site occupancies, but differ in a time dependent phase factor. Thus spectra computed with the dynamics resulting from the exact solution for the classical lattice on one hand and from the ansatz state on the other would differ from each other.

Multiquantum systems and point processes I. Generating functionals and nonlinear semigroups

An algebraic approach to representation theory and the description of multicomponent quantum systems is considered. A generating multiquantum state functional and nonlinear completely positive map are introduced and a dilation theorem giving a nonlinear extension of GNS and Stinenspring theorem is proved. A number particle operator-valued weight and an empirical weight operator generating a macroscopic inductive algebra are defined, and asymptotic commutativity of this algebra is proved. A canonical multiquantum stochastic process called quasi-Poissonian is constructed and the general structure ofthe generator for infinite divisible multi-quantum states as well as multiquantum semigroups is found. An existence theorem extending the Lindblad theorem to unbounded generators as well as nonlinear generators is proved. The class of quasi-free quantum point stochastic processes is introduced to describe Markovian dynamics of non-interacting quantum particles and corresponding birth, branching and current nonlinear semigroups and their generators are studied.