928 research outputs found

    Calculation of nuclear-spin-dependent parity nonconservation in s-d transitions of Ba+^+, Yb+^+ and Ra+^+ ions

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    We use correlation potential and many-body perturbation theory techniques to calculate spin-independent and nuclear spin-dependent parts of the parity nonconserving amplitudes of the transitions between the 6s1/26s_{1/2} ground state and the 5d3/25d_{3/2} excited state of Ba+^+ and Yb+^+ and between the 7s1/27s_{1/2} ground state and the 6d3/26d_{3/2} excited state of Ra+^+. The results are presented in a form convenient for extracting of the constants of nuclear-spin-dependent interaction (such as, e.g., anapole moment) from the measurements.Comment: 9 pages, 8 tables, no figure

    Statistical Theory of Finite Fermi-Systems Based on the Structure of Chaotic Eigenstates

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    The approach is developed for the description of isolated Fermi-systems with finite number of particles, such as complex atoms, nuclei, atomic clusters etc. It is based on statistical properties of chaotic excited states which are formed by the interaction between particles. New type of ``microcanonical'' partition function is introduced and expressed in terms of the average shape of eigenstates F(Ek,E)F(E_k,E) where EE is the total energy of the system. This partition function plays the same role as the canonical expression exp(E(i)/T)exp(-E^{(i)}/T) for open systems in thermal bath. The approach allows to calculate mean values and non-diagonal matrix elements of different operators. In particular, the following problems have been considered: distribution of occupation numbers and its relevance to the canonical and Fermi-Dirac distributions; criteria of equilibrium and thermalization; thermodynamical equation of state and the meaning of temperature, entropy and heat capacity, increase of effective temperature due to the interaction. The problems of spreading widths and shape of the eigenstates are also studied.Comment: 17 pages in RevTex and 5 Postscript figures. Changes are RevTex format (instead of plain LaTeX), minor misprint corrections plus additional references. To appear in Phys. Rev.

    Schiff Theorem Revisited

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    We carefully rederive the Schiff theorem and prove that the usual expression of the Schiff moment operator is correct and should be applied for calculations of atomic electric dipole moments. The recently discussed corrections to the definition of the Schiff moment are absent.Comment: 6 page

    Variation of fundamental constants in space and time: theory and observations

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    Review of recent works devoted to the temporal and spatial variation of the fundamental constants and dependence of the fundamental constants on the gravitational potential (violation of local position invariance) is presented. We discuss the variation of the fine structure constant α=e2/c\alpha=e^2/\hbar c, strong interaction and fundamental masses (Higgs vacuum), e.g. the electron-to-proton mass ratio μ=me/Mp\mu=m_e/M_p or Xe=me/ΛQCDX_e=m_e/\Lambda_{QCD} and Xq=mq/ΛQCDX_q=m_q/\Lambda_{QCD}. We also present new results from Big Bang nucleosynthesis and Oklo natural nuclear reactor data and propose new measurements of enhanced effects in atoms, nuclei and molecules, both in quasar and laboratory spectra.Comment: Proceeding of ACFC, BadHonnef, 2007: to be published in EP

    Comment on "Black hole constraints on varying fundamental constants"

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    In the Letter [1] (also [2]) there is a claim that the generalised second law of thermodynamics (entropy increase) for black holes provides some limits on the rate of variation of the fundamental constants of nature (electric charge e, speed of light c, etc.). We have come to a different conclusion. The results in [1,2] are based on assumption that mass of a black hole does not change without radiation and accreation. We present arguments showing that this assumption is incorrect and give an estimate of the black hole mass variation due to alpha=e^2/\hbar c variation using entropy (and quantum energy level) conservation in an adiabatic process. No model-independent limits on the variation of the fundamental constants are derived from the second law of thermodynamics.Comment: Comment on arXiv:0706.2188 [PRL 99, 061301] by Jane MacGibbo