Quantum fluctuations on curved spacetimes cause the emission of pairs of particles from the quantum vacuum, as in the Hawking effect from black holes. We use an optical analogue to gravity to investigate the influence of the curvature on quantum emission. Due to dispersion, the spacetime curvature varies with frequency here. We analytically calculate for all frequencies the particle flux, correlations and entanglement. We find that horizons increase the flux with a characteristic spectral shape. The photon number correlations transition from multi-to two-mode, with close to maximal entanglement. The quantum state is a diagnostic for the mode conversion in laboratory tests of quantum field theory on curved spacetimes.
PhD in Physics - Thesis "Negative Frequency at the horizon", experimental and theoretical investigation of the scattering of quantum field modes at event horizons in astrophysics and in dispersive media. University of St Andrews, United Kingdom.
https://homepage.univie.ac.at/maxime.jacquet/curr-vitae-mjj.html
the analogue of the event horizon of a black hole to modes of the field. Furthermore, a study of the dispersion of the dielectric shows that five distinct configurations of modes of the inhomogeneous medium at the interface exist as a function of frequency. Thus it is shown that the interface is simultaneously a black- and white-hole horizon-like and horizonless emitter. The role, and importance, of negative-frequency modes of the field in mode conversion at the horizon is established and yields a calculation of the spontaneous photonic flux at the interface.
The spectra are dominated by a negative-frequency mode, which is the partner in any Hawking-type emission. An experiment in which an incoming positive-frequency wave is populated with photons is assembled to observe the transfer of energy to outgoing waves of positive and negative frequency at the horizon. The effect of mode conversion at the interface is clearly shown to be a feature of horizon physics. This is a classical version of the quantum experiment that aims at validating the mechanism of Hawking radiation.
https://www.st-andrews.ac.uk/~qoi/people/Maxime_Jacquet.html
Fortunately, the space-time and fluid medium analogy allows us to create laboratory analogues of event horizons that exhibit high temperature HR. At the horizon, the curvature of space-time is such that it falls at the speed of light: inside the black hole space-time falls towards the central singularity faster than light. Thus the horizon separates two regions of space-time flow: the outside and the inside of the black hole, where the space-time falls at sub- and super-luminal speeds respectively. Because of dispersion - the frequency dependence of the speed of waves in media - it is experimentally possible to use a moving boundary that separates a region of superluminal speed from a region of subluminal speed.
To date, we showed how light in the medium may experience analogue black- or white-hole or horizonless configurations at the boundary, and how the analogue Hawking mechanism of mode mixing then leads to spontaneous emission of radiation.
https://arxiv.org/vc/gr-qc/papers/0612/0612088v1.pdf
and
so then
. Among others, the obtained result proves that quantum vacuum can have regions with a negative effective gravitational charge density. Hence, quantum vacuum, the ‘ocean’ in which all matter of the Universe is immersed, acts as a complex fluid with a very variable gravitational charge density that might include both positive and negative densities;
https://academic.oup.com/mnras/article-abstract/503/4/5091/6177674
https://www.researchgate.net/scientific-contributions/Dragan-Slavkov-Hajdukovic-59375342
Assuming that a particle and its antiparticle have the gravitational charge of the opposite sign, the physical vacuum may be considered as a fluid of virtual gravitational dipoles. Following this hypothesis, we present the first indications that dark matter may not exist and that the phenomena for which it was invoked might be explained by the gravitational polarization of the quantum vacuum by the known baryonic matter.
https://arxiv.org/abs/1106.0847
antimatter somehow “hidden” in cosmic voids; this hypothesis produced encouraging preliminary results. The heart of the third model is the hypothesis that quantum vacuum fluctuations are virtual gravitational dipoles; for the first time, this hypothesis makes possible and inevitable to include the quantum vacuum as a source of gravity.
https://www.worldscientific.com/doi/abs/10.1142/S0217732320300013
https://hal.archives-ouvertes.fr/hal-03177505/document
According to Mercati and his colleagues, there was no special, initial state at all. Instead, a state that gets time pointing forward arises naturally from a universe dictated by gravity. The researchers make this argument in a paper recently published in the journal Physical Review Letters.
How Gravity Explains Why Time Never Runs Backward
Because complexity is increasing in this backward direction, this second arrow of time also points into the past. Which, according to this second time direction, is actually the “future” of another universe that exists on the other side of the Big Bang. (Deep stuff, right?)
http://spaceref.com/news/viewpr.html?pid=716
But say a final condition is imposed. After five minutes, the air molecules have to be back in the 1-metre cube. On Earth, this is clearly an artificial situation. But for Schulman, it is perfectly legitimate to consider such a state of affairs. "There is no reason in principle why the Universe might not have a future boundary condition imposed on it," he says.
When Schulman lets both systems run, he finds that neither arrow of time is destroyed by the other. "All that happens is that Bob adds a bit of noise to Alice and Alice adds a bit of noise to Bob," says Schulman. The two arrows of time are remarkably robust.
"I had no idea when I started my work that this would be the outcome," he says. "The result surprised me as much anyone else." But this surprise, he adds, comes from a prejudice against future boundary conditions. Once you are used to the idea of matter having some memory of what we call its future, it ceases to surprise. From our point of view, the memory of future organisation drags any reverse time region in the direction of increasing order, despite any small disturbances from our own "normal" region.
The paper has created quite a stir. "This is very cool stuff indeed," says Max Tegmark of the University of Pennsylvania. At the Technion-Israel Institute of Technology, where Sculman began this work, Amos Ori agrees. "Schulman has shown that the consistency of a model with two simultaneous time arrows can be explored by relatively simple means. This is a very important observation."
And he has some equivocal support from David Pegg of Griffith University in Brisbane. "I see no obvious flaw in the calculations Schulman has done. He makes his case quite well and I am willing to accept it, at least until convinced otherwise."
Other physicists don't believe that Schulman's computer model is relevant to the real world. According to Paul Davies of the University of Adelaide, a real physical system with a backward arrow would be so fantastically sensitive to an outside influence that it would be easily destroyed. "Imagine a box of gas with molecular velocities reversed to bring about an ordered state," he says. "The gravity of a single electron at the edge of the observable Universe is enough to throw out the motion of a given molecule by 90 degrees after only 20 or so intermolecular collisions. That's pretty sensitive."
Crossing the divide
Surprisingly, Schulman does not dispute Davies' point. "He's absolutely right. But the very set-up of his thought experiment, with initial conditions only, precludes an opposite-directed arrow," he says. "My result applies when boundary conditions are imposed at two separate times."
"We would still feel their gravity, though," says Schulman. "Such reverse-time matter would have all the attributes of the invisible, or 'dark', matter thought to make up most of the mass of our Universe."
1
Black holes, neutrinos and gravitational proprieties of
antimatter
https://arxiv.org/vc/gr-qc/papers/0612/0612088v2.pdf
Causality Is an Effect, II Lawrence S. Schulman
Gamini Piyadasa, C. K. (2020). Antigravity, an Answer to Nature’s Phenomena including the Expansion of the Universe. Advances in High Energy Physics, 2020(), 1–5. doi:10.1155/2020/9315491
An explanation of the quantum-mechanical particle-wave duality is given by the watt-less emission of gravitational waves from a particle described by the Dirac equation. This explanation is possible through the existence of negative energy, and hence negative mass solutions of Einstein’s gravitational field equations. They permit to understand the Dirac equation as the equation for a gravitationally bound positive–negative mass (pole–dipole particle) two-body configuration, with the mass of the Dirac particle equal to the positive mass of the gravitational field binding the positive with the negative mass particle, and with the mass particles making a luminal “Zitterbewegung” (quivering motion), emitting a watt-less oscillating positive–negative space curvature wave. It is shown that this thusly produced “Zitterbewegung” reproduces the quantum potential of the Madelung-transformed Schrödinger equation. The watt-less gravitational wave emitted by the quivering particles is conjectured to be de Broglie’s pilot wave. The hypothesised connection of the Dirac equation to gravitational wave physics could, with the failure to detect gravitational waves by the LIGO antennas and pulsar timing arrays, give a clue to extended theories of gravity, or a correction of astrophysical models for the generation of such waves.
https://orcid.org/0000-0003-1999-4503
. It was also shown that the traditional classical singularity in the core of the SBH is replaced by a quantum oscillator describing a non-singular two-particle system where the two components, named the "nucleus" and the "electron", strongly interact with each other through a quantum gravitational interaction. In agreement with the de Broglie hypothesis, the "electron" is interpreted in terms of the quantum oscillations of the BH horizon.
https://arxiv.org/pdf/2104.05451.pdf
Quantum oscillations in the black hole horizon
https://dipoleantigravity.blogspot.com/
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