An approach to the theory of gravity with an arbitrary reference level of energy density

Five-vectors theory of gravity is proposed, which admits an arbitrary choice of the energy density reference level. This theory is formulated as the constraint theory, where the Lagrange multipliers turn out to be restricted to some class of vector fields unlike the General Relativity (GR), where they are arbitrary. A possible cosmological implication of the proposed model is that the residual vacuum fluctuations dominate during the whole evolution of the universe. That resembles the universe having a nearly linear dependence of a scale factor on cosmic time.

USES OF A SMALL FIELD VALUE WHICH FALLS FROM A METASTABLE MAXIMUM OVER COSMOLOGICAL TIMES

We consider a small, metastable maximum vacuum expectation value b0 of order of a few eV, for a pseudoscalar Goldstone-like field, which is related to the scalar inflaton field ϕ in an idealized model of a cosmological, spontaneously-broken chiral symmetry. The b field allows for relating semi-quantitatively three distinct quantities in a cosmological context. (a) A very small, residual vacuum energy density or effective cosmological constant of [Formula: see text], for λ ~ 3×10-14, the same as an empirical inflaton self-coupling. (b) A tiny neutrino mass, less than b0. (c) A possible small variation downward of the proton to electron mass ratio over cosmological time. The latter arises from the motion downward of the b field over cosmological time, toward a nonzero value. Such behavior is consistent with an equation of motion. We argue that hypothetical b quanta, potentially inducing new long-range forces, are absent, because of negative, effective squared mass in an equation of motion for b-field fluctuations. The assumed flatness of a potential maximum involves a small inverse-time parameter μ ≪ 1/t0, where t0 is the present age of the universe.

DARK-MATTER PARTICLES AND BARYONS FROM INFLATION AND SPONTANEOUS CP VIOLATION IN THE EARLY UNIVERSE

We present aspects of a model which attempts to unify the creation of cold dark matter, a CP-violating baryon asymmetry, and also a small, residual vacuum energy density, in the early universe. The model contains a primary scalar (inflaton) field and a primary pseudoscalar field, which are initially related by a cosmological, chiral symmetry. The nonzero vacuum expectation value of the pseudoscalar field spontaneously breaks CP invariance.

CP NONINVARIANCE AND AN EFFECTIVE COSMOLOGICAL CONSTANT: THE ENERGY DENSITY IN A PSEUDOSCALAR FIELD WHICH ARISES FROM A COSMOLOGICAL, SPONTANEOUSLY-BROKEN CHIRAL SYMMETRY

We present and discuss the properties and the main results of a cosmological model with a spontaneously-broken chiral symmetry. The model contains and relates dynamically, two spin-zero fields. The scalar field can provide the dynamical basis for inflation in the early universe. The pseudoscalar, Goldstone field can provide an early, small residual vacuum energy density, the absolute value of which we estimate to be similar to the present, empirically small vacuum energy density. The small energy scale for this effective cosmological constant is estimated separately, by relating it dynamically to the empirical, small scale of neutrino mass. CP invariance is broken spontaneously. This provides a natural basis for the early generation of an antineutrino–neutrino asymmetry, whose magnitude we estimate, and find to be significant.

CONSTRAINTS ON NO-SCALE SUPERGRAVITY MODELS

We revisit the no-scale mechanism in the context of the simplest no-scale supergravity extension of the standard model. This model has the usual four-dimensional parameter space plus an additional parameter ξ3/2≡m3/2/m1/2. We show how predictions of the model may be extracted over the whole parameter space. A necessary condition for the potential to be stable is Str ℳ4>0. In a class of no-scale supergravity models this condition implies [Formula: see text]. We also calculate the residual vacuum energy at the unification scale [Formula: see text], and find that in typical models one must require C0> 10. Such constraints may be important in the search for a realistic string no-scale supergravity model.

In Situ Hydride Formation in Zirconium and Titanium during Ion Milling

Changes in microstructure of Zr, Ti, and Ti-6%Al-%V resulting from ion-beam sputtering used to prepare samples for transmission electron microscopy have been correlated with hydrogen absorption. Zr was particularly sensitive to this phenomenon, resulting in extensive hydride formation in thin foil samples. Hydrogen enrichment extending to several micrometers in depth could also be produced in bulk samples in a few hours of sputtering. The performance of various sputtering units in different configurations has been examined. It is concluded that hydride formation appears to be caused primarily by the presence of hydrocarbons, for example, from the backstreaming of diffusion pump oil, in the residual vacuum background of the sputtering chamber.