Transformation of subradiant state to superradiant state in a thick resonant medium

The propagation of a step pulse through a thick resonant absorber with homogeneously broadened absorption line is considered. It is shown that a specific subradiant state is naturally developed in the absorber due to the formation of the spatial domains of the atomic coherence with opposite phases. It is proposed to divide the absorber into slices in accord with these domains and place the phase shifters in front of the first slice and between the other slices. If the phase shifters are switched on simultaneously at a particular moment of time, elapsed from the beginning of the step pulse, a strong sharp pulse is generated at the output of the last slice of the absorber. The effect is explained by the phasing of the atomic coherence along all slices of the absorber, which transforms subradiant state of atom-field system to superradiant state.Comment: 14 pages, 4 figure

Varieties of System Transformations and Their Structural Background Based on the IPS Model

This study is the theoretical chapter of a planned book. This book, aims to contribute to the theoretical foundations of similarities and differences in the transformation of party-state systems. Analytical framework of system transformation is based on the extension of the Interactive Party State model (Csan di, 2006) where specifics of the structure and operation of party-state systems and structural background of their disparities were described and analyzed. Self-similarities and disparities of transformation and path-dependency of the variety of systemic outcomes are assigned to structural characteristics of power distribution of party-state systems interpreted as networks. The empirical part of the book uses the Chinese case to test this theory, measuring the dynamics of system transformation, the consequences of short- and long-term external adaptation pressures on the system transformation and long-term consequences of the short-term reactions to these pressures and their spatial disparities. This research was supported by the National Research Foundation in Hungary.system transformation, economic transformation political transformation, sequence of transformation, disparities of transformation, varieties of system outcomes, party-state network

A testability transformation approach for state-based programs

Search based testing approaches are efficient in test data generation; however they are likely to perform poorly when applied to programs with state variables. The problem arises when the target function includes guards that reference some of the program state variables whose values depend on previous function calls. Thus, merely considering the target function to derive test data is not sufficient. This paper introduces a testability transformation approach based on the analysis of control and data flow dependencies to bypass the state variable problem. It achieves this by eliminating state variables from guards and/ or determining which functions to call in order to satisfy guards with state variables. A number of experiments demonstrate the value of the proposed approach

Vitrification of a monatomic 2D simple liquid

A monatomic simple liquid in two dimensions, where atoms interact isotropically through the Lennard-Jones-Gauss potential [M. Engel and H.-R. Trebin, Phys. Rev. Lett. 98, 225505 (2007)], is vitrified by the use of a rapid cooling technique in a molecular dynamics simulation. Transformation to a crystalline state is investigated at various temperatures and the time-temperature-transformation (TTT) curve is determined. It is found that the transformation time to a crystalline state is the shortest at a temerature 14% below the melting temperature Tm and that at temperatures below Tv = 0.6 Tm the transformation time is much longer than the available CPU time. This indicates that a long-lived glassy state is realized for T < Tv.Comment: 5pages,5figures,accepted for publication in CEJ

Contractor renormalization group theory of the SU(NN) chains and ladders

Contractor renormalization group (CORE) method is applied to the SU($N$) chain and ladders in this paper. In our designed schemes, we show that these two classes of systems can return to their original form of Hamiltonian after CORE transformation. Successive iteration of the transformation leads to a fixed point so that the ground state energy and the energy gap to the ground state can be deduced. The result of SU($N$) chain is compared with the one by Bethe ansatz method. The transformation on spin-1/2 ladders gives a finite gap in the excited energy spectra to the ground state in an intuitive way. The application to SU(3) ladders is also discussed.Comment: 4 pages, 4 figures, submitted to Phys. Rev.

Shear Transformation Zones: State Determined or Protocol Dependent?

The concept of a Shear Transformation Zone (STZ) refers to a region in an amorphous solid that undergoes a plastic event when the material is put under an external mechanical load. An important question that had accompanied the development of the theory of plasticity in amorphous solids for many years now is whether an STZ is a {\em region} existing in the material (which can be predicted by analyzing the unloaded material), or is it an {\em event} that depends on the loading protocol (i.e., the event cannot be predicted without following the protocol itself). In this Letter we present strong evidence that the latter is the case. Infinitesimal changes of protocol result in macroscopically big jumps in the positions of plastic events, meaning that these can never be predicted from considering the unloaded material.Comment: 4 pages, 5 figure