It has been shown that an improved estimation of quantum vacuum energy can yield not only acceptable but also experimentally sensible results. The very idea consists in a straightforward extraction of gravitationally interacting part of the full quantum vacuum energy by means of gauge transformations. The implementation of the idea has been performed in the formalism of effective action, in the language of Schwinger's proper time and the Seeley-DeWitt heat kernel expansion, in the background of the Friedmann-Robertson-Walker geometry.Comment: 11 pages, 2 figures, minor improvements, final preprint version, published version: http://www3.interscience.wiley.com/journal/120847180/abstract, devoted to the memory of professor Ryszard Raczka on the occasion of the 11th anniversary of his deat

An abelian version of standard general relativity in the Cartan-Palatini gauge-like formulation in four dimensions has been introduced. Traditional canonical analysis utilizing similarities to the akin Husain-Kuchar SU(2) version of gravity has been performed. The model has been next quantized in the canonical path-integral Faddeev-Popov formalism yielding abelian BF theory.Comment: Minor changes, additional symmetry discussed. 5 pages, 2 columns, REVTeX

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In this paper, we examine whether a quantum computer can efficiently simulate time evolution of two Schrödinger particles. We consider particles interacting with each other and with an external potential. In order to solve the Schrödinger equation in the quantum register, we use an algorithm based on the quantum Fourier transform.

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