The Global Flow of the Schwarzschild - de Sitter Problem for non Negative Energy

2005 ◽  
Author(s):  
Vasile Mioc
Keyword(s):  
Negative Energy ◽  
Global Flow ◽  
De Sitter

scholarly journals ON BOGOLIUBOV TRANSFORMATION OF SCALAR WAVE FUNCTIONS IN DE SITTER SPACE

1994 ◽  
Vol 09 (39) ◽  
pp. 3673-3684 ◽  
Author(s):  
HARU-TADA SATO ◽  
HISAO SUZUKI
Keyword(s):  
Hypergeometric Functions ◽  
Integral Relation ◽  
De Sitter Space ◽  
Negative Energy ◽  
Wave Functions ◽  
The Other ◽  
Bogoliubov Transformation ◽  
Scalar Wave ◽  
De Sitter ◽  
Negative Energy States

We discuss the Bogoliubov transformation of the scalar wave functions caused by the change of coordinates in four-dimensional de Sitter space. It is shown that the exact Bogoliubov coefficients can be obtained from the global coordinates to the static coordinates where there exists manifest horizon. We consider two types of global coordinates. In one global coordinates, it is shown that the Bogoliubov transformation to the static coordinates can be expressed by the discontinuous integral of Weber and Schafheitlin. The positive and negative energy states in the global coordinates degenerate in the static coordinates. In the other global coordinates, we obtain the Bogoliubov coefficients by using the analytic continuation of the hypergeometric functions in two variables. We also discuss the relation between two types of global coordinates and find an integral relation between the mode functions.

Quantum nonthermal radiation of nonstationary rotating de Sitter cosmological model

2014 ◽  
Vol 23 (09) ◽  
pp. 1450077 ◽  
Author(s):  
Irom Ablu Meitei ◽  
T. Ibungochouba Singh ◽  
K. Yugindro Singh
Keyword(s):  
Cosmological Model ◽  
Event Horizon ◽  
Energy Gap ◽  
Energy Levels ◽  
Negative Energy ◽  
Jacobi Method ◽  
De Sitter ◽  
Nonthermal Radiation ◽  
Negative Energy States ◽  
Cosmological Event Horizon

Using the Hamilton–Jacobi method a study of quantum nonthermal radiation of nonstationary rotating de Sitter cosmological model is carried out. It is shown that there exist seas of positive and negative energy states in the vicinity of the cosmological event horizon and there also exists a forbidden energy gap between the two seas. The forbidden energy gap vanishes on the surface of the cosmological event horizon so that the positive and negative energy levels overlap. The width of the forbidden energy gap and the energy of the particle at the cosmological event horizon are found to depend on the cosmological constant, the rotation parameter, positions of the particle and the cosmological event horizon, angular momentum of the particle, evaporation rate and shape of the cosmological event horizon. The tunneling probability of the emitted particles constituting Hawking radiation is also deduced for stationary nonrotating de Sitter cosmological model and the standard Hawking temperature is recovered.

scholarly journals VACUUM FLUCTUATION FORCE ON A RIGID CASIMIR CAVITY IN DE SITTER AND SCHWARZSCHILD–DE SITTER SPACE–TIME

2012 ◽  
Vol 27 (28) ◽  
pp. 1250166 ◽  
Author(s):  
XIANG CHEN
Keyword(s):  
Gravitational Field ◽  
Event Horizon ◽  
Gravitational Force ◽  
De Sitter Space ◽  
Negative Energy ◽  
Space Time ◽  
De Sitter ◽  
Vacuum Fluctuation ◽  
Fluctuation Force ◽  
Weak Gravitational Field

We investigate the net force on a rigid Casimir cavity generated by vacuum fluctuations of electromagnetic field in three cases: de Sitter space–time, de Sitter space–time with weak gravitational field and Schwarzschild–de Sitter space–time. In de Sitter space–time the resulting net force follows the square inverse law but unfortunately it is too weak to be measurable due to the large universe radius. By introducing a weak gravitational field into the de Sitter space–time, we find that the net force can now be split into two parts, one is the gravitational force due to the induced effective mass between the two plates and the other one is generated by the metric structure of de Sitter space–time. In order to investigate the vacuum fluctuation force on the rigid cavity under strong gravitational field, we perform a similar analysis in Schwarzschild–de Sitter space–time and results are obtained in three different limits. The most interesting one is when the cavity gets closer to the horizon of a blackhole, square inverse law is recovered and the repulsive force due to negative energy/mass of the cavity now has an observable strength. More importantly the force changes from being repulsive to attractive when the cavity crosses the event horizon, so that the energy/mass of the cavity switches the sign, which suggests the unusual time direction inside the event horizon.

Multidimensional analysis of the state of Russian studies on the education issues over 1993–2016

2018 ◽  
pp. 50-62
Author(s):  
Дмитрий Рубвальтер ◽  
Dmitry Rubvalter ◽  
Александр Либкинд ◽  
Alexander Libkind ◽  
Валентина Маркусова ◽  
...  
Keyword(s):  
Web Of Science ◽  
The State ◽  
Multidimensional Analysis ◽  
Russian Regions ◽  
Global Flow ◽  
Educational Issues ◽  
Foreign Countries ◽  
High Level ◽  
The Web ◽  
Made In

A multidimensional analysis of the state of Russian studies on the education issues over 1993–2016 was carried out based on the materials of the data contained in the Web of Science (SSCI, A & HCI and SCI-E databases). There were determined the dynamics and trends of a number of relevant indicators, such as the number of Russian publications by year, the share of these publications in the global flow of publications on education issues, the dynamics of the share of publications made in co-authorship with foreign colleagues, etc. A number of distributions of Russian publications on educational issues was compiled and analyzed: by journals, by Russian regions and cities, by organizations and authors of the publications. It was found that most of these distributions were characterized by a high level of non-uniformity. A list of journals (125 titles) in which Russian works on education issues had been published was compiled. Russian organizations (308) and domestic researchers (about two thousand) engaged in studying the issues of education were identified. It was discovered that more than 200 organizations and about 400 academicians from 60 foreign countries had participated in Russian studies on the education issues.

Cosmological spacetimes

2018 ◽  
Author(s):  
Nathalie Deruelle ◽  
Jean-Philippe Uzan
Keyword(s):  
Cosmological Model ◽  
Large Scale ◽  
Cosmic Time ◽  
De Sitter ◽  
Matter Distribution ◽  
Observable Universe ◽  
Cosmological Principle ◽  
Riemannian Spacetime ◽  
The Universe ◽  
Copernican Principle

This chapter provides a few examples of representations of the universe on a large scale—a first step in constructing a cosmological model. It first discusses the Copernican principle, which is an approximation/hypothesis about the matter distribution in the observable universe. The chapter then turns to the cosmological principle—a hypothesis about the geometry of the Riemannian spacetime representing the universe, which is assumed to be foliated by 3-spaces labeled by a cosmic time t which are homogeneous and isotropic, that is, ‘maximally symmetric’. After a discussion on maximally symmetric space, this chapter considers spacetimes with homogenous and isotropic sections. Finally, this chapter discusses Milne and de Sitter spacetimes.

scholarly journals Effects of peroral alanine administration in lactating ewes with decreased availability of glucose

1997 ◽  
Vol 78 (5) ◽  
pp. 805-813 ◽  
Author(s):  
Kjell Holtenius ◽  
Paul Holtenius
Keyword(s):  
Fatty Acids ◽  
Plasma Level ◽  
Free Fatty Acids ◽  
Skeletal Muscles ◽  
Plasma Insulin ◽  
Glucose Oxidation ◽  
Negative Energy ◽  
Crossover Design ◽  
Metabolic Effects ◽  
Significant Elevation

The metabolic effects of a phlorizin-induced drainage of glucose were studied in six lactating ewes with or without peroral alanine drenches in a study of crossover design. Phlorizin gave rise to a small, but significant, elevation of plasma β-hydroxybutyrate. The plasma level of alanine decreased by about 30 % due to the phlorizin injections and alanine was negatively correlated to β-hydroxybutyrate. The plasma level of free fatty acids increased due to phlorizin. Plasma insulin and glucose concentrations were not significantly affected by phlorizin while glucagon level showed a small but significant increase. Peroral alanine drenches to phlorizin-treated ewes gave rise to a transitory elevation of alanine in plasma. The plasma level of free fatty acids was about 40 % lower in phlorizin-treated ewes receiving alanine and β-hydroxybutyrate tended to be lower (P < 0.08). We suggest that β-hydroxybutyrate, apart from its function as an oxidative fuel, might play an important role by limiting glucose oxidation and protein degradation in skeletal muscles during periods of negative energy balance in ruminants. Furthermore, it is suggested that alanine supplementation decreases lipolysis and ketogenesis in lactating ewes.

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