A new warp velocity experiment may provide an indirect verification of physicist Stephen Hawking’s predictions of a black hole. According to the new idea, scientists can catch a glimpse of the ethereal quantum glow that envelops objects traveling at close to the speed of light by coaxing the atom to become invisible. The glow effect, also known as the Unruh effect, appears to fill the space around the accelerating objects with a swarm of virtual particles, bathing those objects in a warm glow. Since the effect is closely related to the Hawking effect, in which virtual particles known as Hawking radiation spontaneously appear on the margins of black holes, scientists have hoped to note one as a sign of the other’s existence for a long time.
However, detecting either effect is very difficult. Hawking radiation is only present at the edge of the black hole, and achieving the necessary acceleration for the Unruh effect will almost certainly necessitate the use of a warp drive.
Now, a new proposal has been published in the magazine Physical Review Letters April 26 has the power to change that. The researchers claim to have discovered a way to dramatically increase the strength of the Unruh effect using a technology that effectively renders the material invisible.
At least, the researchers know there’s a chance they’ll see this effect in their lifetime, said study co-author Vivishek Sudhir, assistant professor of mechanical engineering at MIT and designer of the new experiment. It was a difficult experience, Sudhir added, and there is no guarantee that it will succeed, but that it was their best hope.
After the three scientists who first hypothesized it, the Unruh effect is sometimes known as the Fulling-Davies-Unruh effect. They have eluded detection since they were initially hypothesized in the 1970s, due to the fact that the probability of their detection is very small, and require either massive acceleration or long periods of observation time. According to the prediction, a body accelerating through a vacuum should realize the presence of warm radiation only as a result of its acceleration. Quantum interactions between accelerating matter and quantum fluctuations within the empty space of space cause this phenomenon.
Stephen Hawking predicted in 1974 that the intense gravitational force at the edges of black holes, known as their event horizons, would also produce virtual particles.
Black holes are believed to be not entirely black, said lead author Barbara Oda, a doctoral student in physics at the University of Waterloo in Canada. Instead, they must produce radiation, Hawking discovered.
A stationary atom can only grow its energy by waiting for a real photon to excite one of its electrons, according to quantum theory. However, fluctuations in the quantum field can accumulate to appear as the original photons of an accelerating atom. From the perspective of the accelerating atom, it will pass through a crowd of warm light particles, all of which will heat it up. An obvious symptom would be the heat of the Unruh effect.
However, the acceleration required to achieve the effect is much greater than any particle accelerator available now. To produce a glow hot enough for current detectors, the atom must accelerate to the speed of light in less than a millionth of a second.
Sudhir added that there must have been some unusual acceleration to notice this effect in such a short period of time. “If you instead had some reasonable acceleration, you would have to wait an enormous amount of time – longer than the age of the universe – to see a measurable effect,” he added.
It would be difficult to make this strategy a reality. The researchers plan to build a laboratory-scale particle accelerator that would accelerate an electron to the speed of light as it hits it with a small beam. They intend to conduct experiments with the effect if it can be detected.
Co-author Achim Kempf, professor of applied mathematics at the University of Waterloo, said that while the theories of general relativity and quantum mechanics are in conflict, there should be a unifying theory that explains how things in the universe work.
Kempf added that they were looking for a way to approximate these two huge theories, and this work helps them get there by allowing them to test new hypotheses against experiments.