Quantum Physics, Mini Black Holes, And The Mult... [CRACKED]
"We wanted to see whether [black holes] could have wildly different masses at the same time, and it turns out they do," study lead author Joshua Foo, a PhD researcher in theoretical physics at the University of Queensland, said in a statement (opens in new tab). "Until now, we haven't deeply investigated whether black holes display some of the weird and wonderful behaviors of quantum physics."
Quantum Physics, Mini Black Holes, and the Mult...
However, as it turned out, while a cat in a box could be dead regardless of the observer's actions, a quantum particle may indeed exist in a double state. And the new study indicates that a black hole does as well.
American and Israeli theoretical physicist Jacob Bekenstein was the first to postulate that black holes may have quantum properties. Since a black hole is defined by its mass, its quantum superposition must mean that this odd gravitational gateway can have multiple masses that fall within certain ratios.
Some hypotheses involving additional space dimensions predict that micro black holes could be formed at energies as low as the TeV range, which are available in particle accelerators such as the Large Hadron Collider. Popular concerns have then been raised over end-of-the-world scenarios (see Safety of particle collisions at the Large Hadron Collider). However, such quantum black holes would instantly evaporate, either totally or leaving only a very weakly interacting residue. Beside the theoretical arguments, cosmic rays hitting the Earth do not produce any damage, although they reach energies in the range of hundreds of TeV.
In 1975, Stephen Hawking argued that, due to quantum effects, black holes "evaporate" by a process now referred to as Hawking radiation in which elementary particles (such as photons, electrons, quarks and gluons) are emitted. His calculations showed that the smaller the size of the black hole, the faster the evaporation rate, resulting in a sudden burst of particles as the micro black hole suddenly explodes.
In familiar three-dimensional gravity, the minimum energy of a microscopic black hole is 1016 TeV (equivalent to 1.6 GJ or 444 kWh), which would have to be condensed into a region on the order of the Planck length. This is far beyond the limits of any current technology. It is estimated that to collide two particles to within a distance of a Planck length with currently achievable magnetic field strengths would require a ring accelerator about 1,000 light years in diameter to keep the particles on track.
Hawking's calculation and more general quantum mechanical arguments predict that micro black holes evaporate almost instantaneously. Additional safety arguments beyond those based on Hawking radiation were given in the paper, which showed that in hypothetical scenarios with stable micro black holes massive enough to destroy Earth, such black holes would have been produced by cosmic rays and would have likely already destroyed astronomical objects such as planets, stars, or stellar remnants such as neutron stars and white dwarfs.
It is possible, in some theories of quantum gravity, to calculate the quantum corrections to ordinary, classical black holes. Contrarily to conventional black holes, which are solutions of gravitational field equations of the general theory of relativity, quantum gravity black holes incorporate quantum gravity effects in the vicinity of the origin, where classically a curvature singularity occurs. According to the theory employed to model quantum gravity effects, there are different kinds of quantum gravity black holes, namely loop quantum black holes, non-commutative black holes, and asymptotically safe black holes. In these approaches, black holes are singularity-free.
"Normally, when people think of the multiverse, they think of the many-worlds interpretation of quantum mechanics, where every possibility is actualized," Faizal told Phys.org. "This cannot be tested and so it is philosophy and not science. This is not what we mean by parallel universes. What we mean is real universes in extra dimensions. As gravity can flow out of our universe into the extra dimensions, such a model can be tested by the detection of mini black holes at the LHC. We have calculated the energy at which we expect to detect these mini black holes in gravity's rainbow [a new theory]. If we do detect mini black holes at this energy, then we will know that both gravity's rainbow and extra dimensions are correct."
In some ways, this idea is not new. The LHC has already been trying to detect mini black holes, but has come up empty-handed. This is what would be expected if there are only four dimensions, since the energy required to produce black holes in four dimensions would be much larger (1019 GeV) than the energy that can be achieved at the LHC (14 TeV).
However, if extra dimensions do exist, it is thought that they would lower the energy required to produce black holes to levels that that the LHC can achieve. As Faizal explained, this happens because the gravity in our universe may somehow flow into the extra dimensions. As the LHC has so far not detected mini black holes, it seems that extra dimensions do not exist, at least not at the energy scale that was tested. By extension, the results do not support string theory or parallel universes, either.
In their paper, Ali, Faizal, and Khalil offer a different interpretation for why mini black holes have not been detected at the LHC. They suggest that the current model of gravity that was used to predict the required energy level for black hole production is not quite accurate because it does not account for quantum effects.
According to Einstein's general theory of relativity, gravity can be thought of as the curvature of space and time. However, here the scientists point out that this geometry of space and time responsible for gravity gets deformed at the Planck scale. They have used the new theory of gravity's rainbow to account for this modification of the geometry of space and time near the Planck scale, where the mini black holes are predicted to exist.
Using gravity's rainbow, the scientists found that a little bit more energy is required to produce mini black holes at the LHC than previously thought. So far, the LHC has searched for mini black holes at energy levels below 5.3 TeV. According to gravity's rainbow, this energy is too low. Instead, the model predicts that black holes may form at energy levels of at least 9.5 TeV in six dimensions and 11.9 TeV in 10 dimensions. Since the LHC is designed to reach 14 TeV in future runs, these predicted energy requirements for black hole production should be accessible.
"If mini black holes are detected at the LHC at the predicted energies, not only will it prove the existence of extra dimensions and by extension parallel universes, but it will also solve the famous information paradox in black holes," Ali said. Solving the paradox is possible because, in the gravity's rainbow model, mini black holes have a minimum radius below which they cannot shrink.
In the world of theoretical physics, there is never just one interpretation, and the same goes for this issue. Remo Garattini, Professor of Physics at the University of Bergamo, has used gravity's rainbow in his work on regulating ultraviolet divergences, which have plagued models of quantum gravity. Although he is sympathetic to many of the ideas in gravity's rainbow, he points out that the current paper relies on only one proposal, which uses an equation that does not eliminate divergences.
Their study links the mysterious behavior of black holes to the weird and wonderful world of quantum physics, shedding new light at the same time as highlighting the elusive behavior of the colossal objects.
One example of this behavior is superposition, where subatomic particles can exist in multiple states at the same time. The scientists devised a mathematical framework that simulated a scenario in which a quantum particle sat just outside a massive black hole.
American-Israeli theoretical physicist Jacob Bekenstein was the first to theorize that black holes may have quantum properties. Now, the University of Queensland scientists say their new findings confirm some of Bekenstein's predictions.
Though recent advances, such as the Event Horizon Telescope images of two black holes, add to our knowledge of black holes, we're far from understanding the inner workings of black holes. The new study lends weight to sci-fi depictions of the cosmic giants as colossal gateways that warp space and time in completely unexpected ways.
The new study, based on computer simulations, aims to find an elusive and seamless connection between the principles governing the behavior of supermassive objects, such as black holes, and the smallest subatomic particles.
The research team developed a mathematical framework that placed a simulated quantum particle outside of a simulated supermassive black hole. The simulation showed that the black hole exhibited signs of quantum superposition, the ability to exist in multiple states simultaneously, in this case being both massive and nonmassive.
However, as it turns out, if the cat in the box could die regardless of the observer's actions, then the quantum particle can indeed exist in a dual state. And this new study, published in Physical Review Letters, shows that a black hole can also exist in a binary state.
Israeli-American theoretical physicist Jacob Beckenstein was the first to suggest that black holes might have quantum properties. Since a black hole is defined by its mass, he said, its quantum superposition must mean that these strange gravitational gates can have multiple masses falling under a certain ratio.
It's not right, though, in a number of ways. First off, this visualization is not for real particles, but virtual ones. We are trying to describe the quantum vacuum, but these are not actual particles that you can scoop up or collide with. The particle-antiparticle pairs from quantum field theory are calculational tools only, not physically observable entities. Second, the Hawking radiation that leaves a black hole is almost exclusively photons, not matter or antimatter particles. And third, most of the Hawking radiation doesn't come from the edge of the event horizon, but from a very large region surrounding the black hole. 041b061a72