5,691 research outputs found

    The rate of synthesis and decomposition of tissue proteins in hypokinesia and increased muscular activity

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    During hypokinesia and physical loading (swimming) of rats, the radioactivity of skeletal muscle, liver, kidney, heart, and blood proteins was determined after administration of radioactive amino acids. Tissue protein synthesis decreased during hypokinesia, and decomposition increased. Both synthesis and decomposition increased during physical loading, but anabolic processes predominated in the total tissue balance. The weights of the animals decreased in hypokinesia and increased during increased muscle activity

    Two-color interference stabilization of atoms

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    The effect of interference stabilization is shown to exist in a system of two atomic levels coupled by a strong two-color laser field, the two frequencies of which are close to a two-photon Raman-type resonance between the chosen levels, with open channels of one-photon ionization from both of them. We suggest an experiment, in which a rather significant (up to 90%) suppression of ionization can take place and which demonstrates explicitly the interference origin of stabilization. Specific calculations are made for H and He atoms and optimal parameters of a two-color field are found. The physics of the effect and its relation with such well-known phenomena as LICS and population trapping in a three-level system are discussed.Comment: the paper includes 1 TeX file and 16 picture

    Classification of three-body quantum halos

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    The different kinds of behaviour of three-body systems in the weak binding limit are classified with specific attention to the transition from a true three-body system to an effective two-body system. For weakly bound Borromean systems approaching the limit of binding we show that the size-binding energy relation is an almost universal function of the three s-wave scattering lengths measured in units of a hyperradial scaling parameter defined as a mass weighted average of two-body equivalent square well radii. We explain why three-body halos follow this curve and why systems appearing above reveal two-body substructures. Three-body quantum halos 2-3 times larger than the limit set by zero hypermoment are possible

    The Continuum Structure of the Borromean Halo Nucleus 11Li

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    We solve the Faddeev equations for 11Li (n+n+9Li) using hyperspherical coordinates and analytical expressions for distances much larger than the effective ranges of the interactions. The lowest resonances are found at 0.65 MeV (1/2+, 3/2+, 5/2+) and 0.89 MeV (3/2+, 3/2-) with widths of about 0.35 MeV. A number of higher-lying broader resonances are also obtained and related to the Efimov effect. The dipole strength function and the Coulomb dissociation cross section are also calculated. PACS numbers: 21.45.+v, 11.80.Jy, 21.60.GxComment: 10 pages, LaTeX, 3 postscript figures, psfig.st

    Superfluidity of identical fermions in an optical lattice: atoms and polar molecules

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    In this work, we discuss the emergence of pp-wave superfluids of identical fermions in 2D lattices. The optical lattice potential manifests itself in an interplay between an increase in the density of states on the Fermi surface and the modification of the fermion-fermion interaction (scattering) amplitude. The density of states is enhanced due to an increase of the effective mass of atoms. In deep lattices, for short-range interacting atoms, the scattering amplitude is strongly reduced compared to free space due to a small overlap of wavefunctions of fermions sitting in the neighboring lattice sites, which suppresses the pp-wave superfluidity. However, we show that for a moderate lattice depth there is still a possibility to create atomic pp-wave superfluids with sizable transition temperatures. The situation is drastically different for fermionic polar molecules. Being dressed with a microwave field, they acquire a dipole-dipole attractive tail in the interaction potential. Then, due to a long-range character of the dipole-dipole interaction, the effect of the suppression of the scattering amplitude in 2D lattices is absent. This leads to the emergence of a stable topological px+ipyp_x+ip_y superfluid of identical microwave-dressed polar molecules.Comment: 14 pages, 4 figures; prepared for proceedings of the IV International Conference on Quantum Technologies (Moscow, July 12-16, 2017); the present paper summarizes the results of our studies arXiv:1601.03026 and arXiv:1701.0852
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