Positive Vacuum Research Articles

COSMIC ACCELERATION: INHOMOGENEITY VERSUS VACUUM ENERGY

In this letter, we present an alternative explanation for the cosmic acceleration which appears as a consequence of recent high redshift supernova data. In the usual interpretation, this cosmic acceleration is explained by the presence of a positive cosmological constant or vacuum energy, in the background of Friedmann models. Instead, we shall consider a local rotational symmetric (LRS) inhomogeneous space–time, with a barotropic perfect fluid equation of state for the cosmic matter. Within this framework the kinematical acceleration of the cosmic fluid or, equivalently, the inhomogeneity of matter, is just the responsible of the SNe Ia measured cosmic acceleration. Although in our model the Cosmological Principle is relaxed, it maintains local isotropy about our worldline in agreement with CBR observations.

Foundations of Vacuum Science and Technology

Kinetic Theory of Gases. Flow of Gases Through Tubes and Orifices. Positive Displacement Vacuum Pumps. Kinetic Vacuum Pumps. Capture Vacuum Pumps. Vacuum Gauges. Partial Pressure Analysis. Leak Detection and Leak Detectors. High-Vacuum System Design. Gas-Surface Interactions and Diffusion. Ultrahigh and Extreme High Vacuum. Calibration and Standards Appendix. Indexes.

A low matter density decaying vacuum cosmology from a complex metric

A low matter density decaying vacuum cosmology is proposed on the assumption that the universe's radius is a complex quantity if it is regarded as having a zero energy - momentum tensor. But we find that when the radius is real, it contains matter. Using the Einstein - Hilbert action principle, the physical scale factor is obtained as equal to with representing the finite radius of the universe at t = 0. The resulting physical picture is roughly a theoretical justification of the old Ozer - Taha model. The new model is devoid of all cosmological problems. In particular, it confirms the bounds on , the present value of the Hubble parameter: and faces no age problem. We argue that the total energy density consists of parts corresponding to relativistic/non-relativistic matter, a positive vacuum energy, a negative energy and a form of matter with equation of state (textures or generally K-matter), and the following predictions are made for the present non-relativistic era: , , , where a parameter corresponding to K-matter is taken to be unity. It is shown that spacetime with a complex metric has signature changing properties. Using quantum cosmological considerations, it is shown that the wavefunction is peaked about the classical contour of evolution and the minimum radius of the non-singular model is predicted as comparable with the Planck length.

Measuring the cosmological constant with redshift surveys

It has been proposed that the cosmological constant $\Lambda$ might be measured from geometric effects on large-scale structure. A positive vacuum density leads to correlation-function contours which are squashed in the radial direction when calculated assuming a matter-dominated model. We show that this effect will be somewhat harder to detect than previous calculations have suggested: the squashing factor is likely to be $<1.3$, given realistic constraints on the matter contribution to $\Omega$. Moreover, the geometrical distortion risks being confused with the redshift-space distortions caused by the peculiar velocities associated with the growth of galaxy clustering. These depend on the density and bias parameters via the combination $\beta\equiv \Omega^{0.6}/b$, and we show that the main practical effect of a geometrical flattening factor $F$ is to simulate gravitational instability with $\beta_{\rm eff}\simeq 0.5(F-1)$. Nevertheless, with datasets of sufficient size it is possible to distinguish the two effects; we discuss in detail how this should be done. New-generation redshift surveys of galaxies and quasars are potentially capable of detecting a non-zero vacuum density, if it exists at a cosmologically interesting level.

The use of SR for the creation of a topology in layers of metal phthalocyanines

The influence of synchrotron radiation (SR) on vacuum-deposited layers of copper and aluminium phthalocyanines is investigated. For the creation of patterns in these layers X-ray radiation exposure and vacuum thermal development were used. It was established, that the layers of copper phthalocyanine (CuPc) possess the properties of both positive and negative vacuum X-ray resist upon radiation exposures of 5 kJ/cm 3 and 35 kJ/cm 3, respectively. The layers of aluminium phthalocyanine (AlPcX, where X = Cl, F, OH) possess the properties of only negative vacuum X-ray resists. The possibility of the creation of a submicron topology in layers of metal phthalocyanines has been demonstrated.

Dynamical supersymmetry breaking and asymptotic freedom in non-Abelian gauge theories.

We extend Witten's result that dynamical supersymmetry breaking does not occur in non-Abelian gauge theories which do not depend on a vacuum angle. It is shown that the possibility of dynamical supersymmetry breaking in supersymmetric non-Abelian gauge theories is intimately related to the asymptotic freedom of Yang-Mills theories. In supersymmetric non-Abelian gauge theories with asymptotic freedom, dynamical supersymmetry breaking does not occur through a positive vacuum energy for an arbitrary gauge coupling constant regardless of any dependence on the vacuum angle in the theories, assuming the full gauge symmetry in the limit of small $g$ in the quantum theory. Such a special example is the minimal supersymmetric non-Abelian gauge theories in four dimensions.

Instability of forever anisotropic, expanding, vacuum-dominated cosmological models

The cosmological 'no hair' conjecture states that the repulsive gravitational effect of a positive vacuum energy asymptotically leads to de Sitter geometry locally. Some restricted proofs have been given, but also some counterexamples showing that the 'no hair' conjecture has a limited validity. In this paper the author shows that vacuum-dominated cosmological models with eternal expansion, but which does not tend towards the de Sitter geometry, are dynamically unstable. Metrical perturbations of these models lead either to inflation or to collapse.

About the Immediate Future of Modern Art

crisis was a great delayed reaction which the more perceptive of observers are now wrestling with-(not least the artists, although they have consistently denied that any kind of break has occurred, as has the entire support symbiosis): art as realty, art as a surrogate secular (cultural) religion. The commercial temples! There is, as yet, a 'positive vacuum' i.e. no healthy plenum ... only decadent posturing, and worse, academic gainsaying. Secular monitors-such as the Marxists-have gone on preaching, but the irrelevance of what they offer is well known and need not be answered.

Positive energy theorem and vacuum states for the Einstein-Maxwell system

In this paper we will state the positive energy theorem for N = 2 supergravity which corresponds to the Einstein-Maxwell system. We will also find all ground state of this theory that turns out to be Bertotti-Robinson or pp-wave space-times.

Supersymmetry is afraid of condensates

Abstract Supersymmetry is never broken by pair condensates of chiral superfields: the supersymmetry breaking part of Green's functions satisfies an equation which always has an identically vanishing solution. Hence any phase containing pair condensates is unstable due to its positive vacuum energy.

Particle Phase Transitions can Prevent an Initial Cosmological Singularity

The present universe has small vacuum energy density (cosmological constant) and small spatial curvature. Therefore, before symmetry breaking, it had to have huge positive vacuum energy density, significant curvature, and low entropy. Because the energy positivity condition was not then satisfied, there need not have been an initial singularity (Hot Big Bang). If the universe is spatially open or the initial entropy high enough, then before the elementary particle phase transition, it was indeed an inflecting universe with an initial singularity. But if the universe is spatially closed and of low initial entropy, it needed to be a curvature-dominated bouncing universe, with a minimum size and maximum temperature (Tepid Little Bang). The closure of the present universe will therefore determine whether or not there was an initial singularity.

High throughput pumping of dangerous gases with a multistage roots vacuum pump

The pumping of critical gases—high‐purity, expensive, or dangerous gases—in the vacuum range from 10−3 mbar (1 micron) to atmospheric pressure at specified temperatures and with a minimum of contamination is discussed. A reasonable solution to the problems arising in this field is a positive displacement vacuum pump—a special roots vacuum pump—which requires no lubrication in the working chamber and no mechanical contact between rotors and housing, but which, due to a cooling process free of foreign media, can pump with high compression ratios. A specially designed multistage roots vacuum pump, to pump UF6 from a centrifuge uranium‐separating installation is described. This pump has a maximum pumping speed for nitrogen of 220 m3/h (130 cfm) and can compress directly from below 10 mbar to atmospheric pressure.

Quantum vacuum energy in a closed universe

The problem of defining the vacuum energy and pressure of quantized fields in the static Einstein universe is considered. A regularization procedure which utilizes a wavelength cutoff in the mode sum is discussed and applied to the cases of the massive conformally coupled scalar field, the electromagnetic field, and the neutrino field. In all cases a positive vacuum energy density and pressure are obtained. In the case of the massive scalar field it is possible for the vacuum pressure to exceed the vacuum energy density, thus violating the dominant energy condition. For the electromagnetic and neutrino fields the energy density and pressure are of the form $\ensuremath{\rho}=\ensuremath{\gamma}\overline{h}\frac{c}{{a}^{4}}$ and $P=\frac{\ensuremath{\rho}}{3}$, respectively, where $\ensuremath{\gamma}=\frac{11}{240{\ensuremath{\pi}}^{2}}$ for the electromagnetic field and $\ensuremath{\gamma}=\frac{17}{1920{\ensuremath{\pi}}^{2}}$ for the neutrino field, and where $a$ is the radius of the universe.

A positive action vacuum valve

A positive action vacuum valve