A Mathematical Proof That The Universe Could Have Formed Spontaneously From Nothing — The Physics arXiv Blog — Medium: The new proof is based on a special set of solutions to a mathematical entity known as the Wheeler-DeWitt equation...
In each of these cases, they find a solution in which the bubble can expand exponentially and thereby reach a size in which a universe can form—a Big Bang...
Showing posts with label cosmological constant. Show all posts
Showing posts with label cosmological constant. Show all posts
Friday, April 11, 2014
Monday, June 4, 2012
Dark matter, dark energy, dark… magnetism?
Dark matter, dark energy, dark… magnetism?: In 2008 at the Complutense University of Madrid, Spain, they were playing with a particular version of a mutant gravity model called a vector-tensor theory, which they had found could mimic dark energy. Then came a sudden realisation. The new theory was supposed to be describing a strange version of gravity, but its equations bore an uncanny resemblance to some of the mathematics underlying another force. "They looked like electromagnetism," says Beltrán, now based at the University of Geneva in Switzerland. "We started to think there could be a connection."
So they decided to see what would happen if their mathematics described not masses and space-time, but magnets and voltages...
Crucially, inflation could also have boosted the new electromagnetic waves. Beltrán and Maroto found that this process would leave behind vast temporal modes: waves of electric potential with wavelengths many orders of magnitude larger than the observable universe. These waves contain some energy but because they are so vast we do not perceive them as waves at all.
So they decided to see what would happen if their mathematics described not masses and space-time, but magnets and voltages...
Crucially, inflation could also have boosted the new electromagnetic waves. Beltrán and Maroto found that this process would leave behind vast temporal modes: waves of electric potential with wavelengths many orders of magnitude larger than the observable universe. These waves contain some energy but because they are so vast we do not perceive them as waves at all.
Tuesday, April 19, 2011
[1104.3654] Cosmological extrapolation of MOND
[1104.3654] Cosmological extrapolation of MOND: "Regime of MOND, which is used in astronomy to describe the gravitating systems of island type without the need to postulate the existence of a hypothetical dark matter, is generalized to the case of homogeneous distribution of usual matter by introducing a linear dependence of the critical acceleration on the size of region under consideration. We show that such the extrapolation of MOND in cosmology is consistent with both the observed dependence of brightness on the redshift for type Ia supernovae and the parameters of large-scale structure of Universe in the evolution, that is determined by the presence of a cosmological constant, the ordinary matter of baryons and electrons as well as the photon and neutrino radiation without any dark matter."
Friday, March 18, 2011
Physicists investigate lower dimensions of the universe
Physicists investigate lower dimensions of the universe: So far, there may already be one piece of experimental evidence for the existence of a lower-dimensional structure at a higher energy scale. When observing families of cosmic ray particles in space, scientists found that, at energies higher than 1 TeV, the main energy fluxes appear to align in a two-dimensional plane. This means that, above a certain energy level, particles propagate in two dimensions rather than three dimensions.
In the current study, Mureika and Stojkovic have proposed a second test for lower dimensions that would provide independent evidence for their existence. The test is based on the assumption that a (2 + 1)-dimensional spacetime, which is a flat plane, has no gravitational degrees of freedom. This means that gravity waves and gravitons cannot have been produced during this epoch. So the physicists suggest that a future gravitational wave detector looking deep into space might find that primordial gravity waves cannot be produced beyond a certain frequency, and this frequency would represent the transition between dimensions. Looking backwards, it would appear that one of our spatial dimensions has “vanished.”
The scientists added that it should be possible, though perhaps more difficult, to test for the existence of (1 + 1)-dimensional spacetime.
In the current study, Mureika and Stojkovic have proposed a second test for lower dimensions that would provide independent evidence for their existence. The test is based on the assumption that a (2 + 1)-dimensional spacetime, which is a flat plane, has no gravitational degrees of freedom. This means that gravity waves and gravitons cannot have been produced during this epoch. So the physicists suggest that a future gravitational wave detector looking deep into space might find that primordial gravity waves cannot be produced beyond a certain frequency, and this frequency would represent the transition between dimensions. Looking backwards, it would appear that one of our spatial dimensions has “vanished.”
The scientists added that it should be possible, though perhaps more difficult, to test for the existence of (1 + 1)-dimensional spacetime.
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