scholarly journals Distribution of energy density of Dirac field in the closed universe

1970 ◽  
Vol 9 (9) ◽  
pp. 1-3
Author(s):  
SK Sharma ◽  
U Khanal
Keyword(s):  
Energy Density ◽  
Finite Energy ◽  
Negative Energy ◽  
Field Energy ◽  
Dirac Field ◽  
Closed Universe ◽  
Frw Universe ◽  
Energy Current ◽  
Large Structures ◽  
Energy Flows

The behavior of the energy of the free Dirac field in the closed FRW universe has been looked at. It is generally expected that the comoving energy density for the particles is conserved. Although this expectation is true for the massless fields, it is not for the massive ones. So, there is a finite energy current in any finite sized volume of the universe. The energy current is positive throughout for lowest state, n = 0. For n = 1, however, there occurs negative energy flow near r = π/2. So energy flows out of the region. It may be expected that the two regions, on either sides may become disjoint over time, but this can be confirmed only after studying the time evolution. If confirmed, this could explain the process of fragmentation of large structures. Larger n appears to produce larger number of such density contrasts. Key words: Closed Universe; Dirac field; Energy DensityDOI: http://dx.doi.org/10.3126/sw.v9i9.5492SW 2011; 9(9): 1-3

Restrictions on negative energy density for the Dirac field in flat spacetime

2006 ◽  
Vol 15 (5) ◽  
pp. 934-939 ◽  
Author(s):  
Shu Wei-Xing ◽  
Yu Hong-Wei ◽  
Li Fei ◽  
Wu Pu-Xun ◽  
Ren Zhong-Zhou
Keyword(s):  
Energy Density ◽  
Negative Energy ◽  
Dirac Field ◽  
Negative Energy Density ◽  
Flat Spacetime

scholarly journals Particle number and current in Dirac field in the closed universe

1970 ◽  
Vol 9 (9) ◽  
pp. 4-7
Author(s):  
PR Dhungel ◽  
U Khanal
Keyword(s):  
Particle Number ◽  
Particle Number Density ◽  
Dirac Field ◽  
Closed Universe ◽  
Frw Universe ◽  
Frw Model ◽  
The Universe ◽  
Particle Current ◽  
Massless Fields ◽  
Finite Particle

The behavior of the particle number and particle current of the free Dirac field in the closed FRW universe has been explored. Although the particle number is conserved for the massless fields as expected, it is not for the massive ones. So, there is a finite particle current in any finite sized volume of the universe. Such currents tend to enhance the density contrast over time. It is seen that the momenta of the Dirac particle is quantized in a closed FRW model. The particles distribute themselves in such a way as to resemble that required for the flattened rotation curves of galaxies. Key words: Closed Universe; Dirac field; Comoving particle number density DOI: http://dx.doi.org/10.3126/sw.v9i9.5508 SW 2011; 9(9): 4-7

CLASSICAL GHOSTS AND THE COSMOLOGICAL CONSTANT

2004 ◽  
Vol 19 (31) ◽  
pp. 5317-5324
Author(s):  
T. HIRAYAMA
Keyword(s):  
Energy Density ◽  
Cosmological Constant ◽  
Parameter Space ◽  
Large Time ◽  
Finite Energy ◽  
Negative Energy ◽  
Scale Factor ◽  
Large Region ◽  
Unstable Behavior ◽  
Negative Cosmological Constant

For a large region of parameter space involving the cosmological constant and mass parameters, we discuss spacetime solutions that are effectively Minkowskian on large time and distance scales. A negative energy fluid is involved, resulting in a scale factor oscillating about a constant, with a frequency determined by the size of a negative cosmological constant. Gravity itself induces a coupling between the ghost-like and normal fields, and we find that this results in stochastic rather than unstable behavior. Ghosts could also allow for the existence of Lorentz invariant fluctuating solutions of finite energy density.

scholarly journals Dynamics of O(N) chiral supersymmetry at finite energy density

2001 ◽  
Vol 520 (3-4) ◽  
pp. 317-321 ◽  
Author(s):  
J. Baacke ◽  
D. Cormier ◽  
H.J. de Vega ◽  
K. Heitmann
Keyword(s):  
Energy Density ◽  
Finite Energy

NEGATIVE ENERGY DENSITY IN SPINNING MATTER SOURCES IN WORMHOLE SPACE–TIMES WITH TORSION

1998 ◽  
Vol 13 (38) ◽  
pp. 3069-3072
Author(s):  
L. C. GARCIA DE ANDRADE
Keyword(s):  
Energy Density ◽  
Spin Density ◽  
Gravitational Collapse ◽  
Negative Pressure ◽  
Negative Energy ◽  
Space Time ◽  
Negative Energy Density ◽  
Traversable Wormholes ◽  
Radial Tension

Negative energy densities in spinning matter sources of non-Riemannian ultrastatic traversable wormholes require the spin energy density to be higher than the negative pressure or the radial tension. Since the radial tension necessary to support wormholes is higher than the spin density in practice, it seems very unlikely that wormholes supported by torsion may exist in nature. This result corroborates earlier results by Soleng against the construction of the closed time-like curves (CTC) in space–time geometries with spin and torsion. It also agrees with earlier results by Kerlick according to which Einstein–Cartan (EC) gravity torsion sometimes enhance the gravitational collapse instead of avoiding it.

scholarly journals Energy current and computing

2018 ◽  
Vol 376 (2134) ◽  
pp. 20170449 ◽  
Author(s):  
Alex Yakovlev
Keyword(s):  
Digital Circuit ◽  
Electrical Networks ◽  
Mathematical Methods ◽  
Power Sources ◽  
Energy Current ◽  
Energy Flows ◽  
State Changes ◽  
Spatio Temporal ◽  
Computational Circuits ◽  
Physical Phenomena

In his seminal Electrical papers , Oliver Heaviside stated ‘We reverse this …' referring to the relationship between energy current and state changes in electrical networks. We explore implications of Heaviside's view upon the state changes in electronic circuits, effectively constituting computational processes. Our vision about energy-modulated computing that can be applicable for electronic systems with energy harvesting is introduced. Examples of analysis of computational circuits as loads on power sources are presented. We also draw inspiration from Heaviside's way of using and advancing mathematical methods from the needs of natural physical phenomena. A vivid example of Heavisidian approach to the use of mathematics is in employing series where they emerge out of the spatio-temporal view upon energy flows. Using series expressions, and types of natural discretization in space and time, we explain the processes of discharging a capacitive transmission line, first, through a constant resistor and, second, through a voltage controlled digital circuit. We show that event-based models, such as Petri nets with an explicit notion of causality inherent in them, can be instrumental in creating bridges between electromagnetics and computing. This article is part of the theme issue ‘Celebrating 125 years of Oliver Heaviside's ‘Electromagnetic Theory’’.

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