4,560 research outputs found

    Power-law expansion cosmology in Schr\"odinger-type formulation

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    We investigate non-linear Schr\"{o}dinger-type formulation of cosmology of which our cosmological system is a general relativistic FRLW universe containing canonical scalar field under arbitrary potential and a barotropic fluid with arbitrary spatial curvatures. We extend the formulation to include phantom field case and we have found that Schr\"{o}dinger wave function in this formulation is generally non-normalizable. Assuming power-law expansion, atqa \sim t^q, we obtain scalar field potential as function of time. The corresponding quantities in Schr\"{o}dinger-type formulation such as Schr\"{o}dinger total energy, Schr\"{o}dinger potential and wave function are also presented.Comment: 9 pages, 5 figures, Revtex 4, accepted by Astroparticle Physics, more Ref. adde

    Universal dielectric loss in amorphous solids from simultaneous bias and microwave field

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    We derive the ac dielectric loss in glasses due to resonant processes created by two-level systems and a swept electric field bias. It is shown that at sufficiently large ac fields and bias sweep rates the nonequilibrium loss tangent created by the two fields approaches a universal maximum determined by the bare linear dielectric permittivity. In addition this nonequilibrium loss tangent is derived for a range of bias sweep rates and ac amplitudes and show that the loss tangent creates a predicted loss function that can be understood in a Landau-Zener theory and which can be used to extract the TLS density, dipole moment, and relaxation rate.Comment: To appear in Physical Review Letters, 4 pages, 3 figure
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