Creating a Laboratory Simulation of a Black Hole: Physicists’ Latest Endeavor!

An artificial analogue of a black hole could tell us something about the theoretically elusive radiation emitted by a real thing.

Using a string of atoms in a single file to simulate a black hole’s event horizon, a team of physicists observed the equivalent of what we call Hawking radiation – particles generated by perturbations of quantum fluctuations caused by the black hole’s destruction in spacetime.

This, they say, could help resolve the contradiction between two currently irreconcilable concepts of describing the universe: general relativity, which describes the behavior of gravity as a continuous field known as spacetime; and quantum mechanics, which describes the behavior of discrete particles using the mathematics of probability.

For a universally applicable unified theory of quantum gravity, these two theories must find a way to coincide in some way.

This is where black holes come into play, perhaps the strangest and most extreme phenomena in the universe. And these massive objects are so incredibly dense that they don’t have enough speed to get within a certain distance of the black hole’s center of mass in the universe. Not even the speed of light.

This distance, which varies with the mass of the black hole, is called the event horizon. Once the body goes beyond its limits, we can only imagine what happens, since nothing returns vital information about its fate.

But in 1974, Stephen Hawking suggested that the gaps in quantum fluctuations caused by the event horizon give rise to a type of radiation very similar to thermal radiation.

And if Hawking radiation exists, it’s still too weak for us to detect. We can never separate it from the quiet hiss of the universe. But we can explore its properties by creating analogues of a black hole in the laboratory.

This has been done before, but in a study published last year led by Lotte Mertens of the University of Amsterdam in the Netherlands, the researchers did something new.

A chain of one-dimensional atoms served as a path for electrons to “jump” from one place to another. By adjusting the ease with which this mobility can occur, physicists can cause certain properties to disappear, effectively creating a kind of event horizon that is superimposed on the undulating nature of electrons.

The team said that this false event horizon effect resulted in a temperature increase that is in line with theoretical predictions for an equivalent black hole system, but only when part of the chain escapes the event horizon.

This could mean that entanglement of particles extending beyond the event horizon is useful for generating Hawking radiation.

The simulated Hawking radiation was thermal only for a certain range of amplitude jumps and in simulations that began to mimic the type of spacetime considered “flat”.

This indicates that Hawking radiation can only be convective in a number of situations where there is a curvature of space-time due to gravity.

It’s not clear what this means for quantum gravity, but the model offers a way to study the appearance of Hawking radiation in a medium unaffected by the wild dynamics of black hole formation. Because it is so simple, it can be run under a wide variety of experimental conditions, the researchers said.

“This could open up a field for studying fundamental aspects of quantum mechanics beyond gravity and curvilinear voids in various condensed matter conditions,” the researchers explain in their paper.

The study is published in the journal Physical Review Research.

Source: Science Alert