The classical equation of motion for a particle moving in the new double-well potential V(x) = ½ V_{0}(A cosh ax - 1)^{2} is solved exactly for different values of the parameter A and the energy constant E. The solutions in various special cases are discussed.
Motivated by the properties of one-dimensional lattice systems with asymmetric on-site potential, one can formulate a hypothesis of an asymmetry driven phase transformation. Characteristic feature of one-dimensional systems exhibiting asymmetry driven phase transformation is a sequence of the two phase conversions. In particular class of such systems with a triple-well potential, phase conversions of one-dimensional systems would evolve into a sequence of two phase transitions in three-dimensional models. We propose here a model of three-dimensional system exhibiting a sequence of two first order asymmetry driven phase transitions.
One of the possible ways of formulation of an information loss paradox refers to an entanglement of the two particles created in a vicinity of an event horizon. Evolution of the entangled particles and an interaction with their own environments should lead to a decay of the entanglement. However obvious, such a perspective appears to be too naive in this case.
We theoretically study possible domain-type collective dimerizations of graphite induced by inter-layer charge transfer excitations in the visible region. Using the semiempirical Brenner theory, we have calculated the adiabatic energy along the path that starts from original two distant graphite layers, but finally reaches the dimerized domain which consists of about 100 carbons with inter-layer σ-bonds. The energy barrier between this new domain and the starting graphite is shown to be of the order of 1 eV, being easily overcome by applying a few visible photons. We have also shown the optimal path of transformation via step by step increase of the domain size.
Recent experiments indicate that a photostimulated graphite with a femtosecond laser pulse results in the formation of a stable domain with sp^3 like interlayer bonds. By means of the energy barrier minimization and molecular dynamics using the empirical Brenner potential we study a geometrical structure of the new phase. We clarify proliferation of the initial domain and prove that the overall process is a multiphoton one. Furthermore, we present a model describing the initial transformation - an interlayer charge transfer resulting in the localization of an exciton-like state. The local density approximation electronic structure analysis reveals that the electronic state of the new phase is an insulator immersed in semimetal. We study by means of the long-range carbon bond order potential the effect of the existence of the new phase on the surrounding graphite and propose a new mid step structure on the path of a photoinduced graphite-diamond conversion.
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