An interaction of electromagnetic field with a nanostructure composed of two quantum dots is studied theoretically. An effect of a resonant electron transfer between the localized low-lying states of quantum dots is predicted. A necessary condition for such an effect is the existence of an excited bound state whose energy lies close to the top of the barrier separating the quantum dots. This effect may be used to realize the reversible quantum logic gate NOT if the superposition of electron states in different quantum dots is viewed as the superposition of bits 0 and 1.

The reasons for the anomalously high thermal stability of cubane C8H8 and the mechanisms of its decomposition are studied by numerically simulating the dynamics of this metastable cluster at T = 1050 - 2000 K using a tight-binding potential. The decomposition activation energy is found from the temperature dependence of the cubane lifetime obtained from the numerical experiment; this energy is fairly high, Ea = 1.8 - 2.0 eV. The decomposition products are, as a rule, either C6H6 and C2H2 molecules or the isomer C8H8 with a lower energy.Comment: 5 figure

The combined effect of both nonmagnetic and magnetic impurities on the superconducting transition temperature is studied theoretically within the BCS model. An expression for the critical temperature as a function of potential and spin-flip scattering rates is derived for a two-dimensional superconductor with arbitrary in-plane anisotropy of the superconducting order parameter, ranging from isotropic s-wave to d-wave (or any pairing state with nonzero angular momentum) and including anisotropic s-wave and mixed (d + s)-wave as particular cases. This expression generalizes the well-known Abrikosov-Gor'kov formula for the critical temperature of impure superconductors. The effect of defects and impurities in high temperature superconductors is discussed.

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