A Nonperturbative Calculation of Basic Chiral QCD Parameters Within Zero Modes Enhancement Model of the QCD Vacuum. II

Basic chiral QCD parameters (the pion decay constant, the quark and gluon condensates, the dynamically generated quark mass, etc) as well as the vacuum energy density (up to the sign, by definition, the bag constant) have been calculated from first principles within a recently proposed zero modes enhancement (ZME) model of the true QCD vacuum. Our unique input data was chosen to be the pion decay constant in the chiral limit as given by the chiral perturbation theory at the hadronic level (CHPTh). In order to analyze our numerical results we set a scale by two different ways. In both cases we obtain almost the same numerical results for all chiral QCD parameters. Phenomenological estimates of these quantites as well as vacuum energy density are in good agreement with our numerical results. Complementing them by the numerical value of the instanton contribution to the vacuum energy density, we predict new, more realistic values for the vacuum energy density, the bag constant and the gluon condensate.Comment: 22 pages in total , 8 figures, 4 tables ; RevTex package use

A nonperturbative calculation of basic chiral QCD parameters within zero modes enhancement model of the QCD vacuum, 2

Basic chiral QCD parameters (the pion decay constant, quark and gluon condensates, the dynamically generated quark mass, etc) as well as the vacuum energy density have been calculated from first principles within a recently proposed zero modes enhancement (ZME) model of the QCD true vacuum. It is based on the solution to the Schwinger-Dyson (SD) equation for the quark propagator in the infrared (IR) domain. In order to analyze our numerical results we set a scale by the two different ways. First this was done at a scale responsible for dynamical chiral symmetry breaking (DCSB) at the fundamental quark level \Lambda_{CSBq}, defined as the double of the dynamically generated light quark mass m_d. In the second case m_d was reasonably taken to be 300 \le m_d \le 400 \ (MeV) otherwise first remains arbitrary. Our unique input data was chosen to be the pion decay constant in the chiral limt given by the chiral perturbation theory at the hadronic level (CHPTh). With the help of the nonperturbative gluon contributions to the vacuum energy density one can establish realistic lower bounds for the m_d. In both cases we obtain almost the same numerical results for all chiral QCD parameters. Phenomenological estimates of these quantites are in good agreement with our numerical results. Also our numerical result for the vacuum energy density agrees well with the QCD sum rules and random instanton liquid model (RILM) values for this quantity. One of the most important our conclusions is that the above mentioned scale of DCSB at the fundamental quark level \Lambda_{CSBq} and the scale at which confinement occurs \Lambda_c are nearly the same indeed. Nonperturbative vacuum structure, which emerges from the ZME model, appears to be well suited to describe quark confinement, DCSB, the Goldstone nature of th

Ultrastable Optical Clock with Neutral Atoms in an Engineered Light Shift Trap

An ultrastable optical clock based on neutral atoms trapped in an optical lattice is proposed. Complete control over the light shift is achieved by employing the $5s^2 {}^1S_0 \to 5s5p {}^3P_0$ transition of ${}^{87}{\rm Sr}$ atoms as a "clock transition". Calculations of ac multipole polarizabilities and dipole hyperpolarizabilities for the clock transition indicate that the contribution of the higher-order light shifts can be reduced to less than 1 mHz, allowing for a projected accuracy of better than $10^{-17}$.Comment: 4 pages, 2 figures, accepted for publication in Phys. Rev. Let