Black hole analogs could theoretically tell us a few things about the elusive radiation that the real thing emits.
In 2022, a team of physicists used a chain of atoms in a single row to simulate the event horizon of a black hole, using so-called Hawking radiation (particles that result from the disruption of quantum fluctuations caused by a black hole’s entry). I observed something equivalent to what is called. Space-time.
This could help resolve the tension between two currently contradictory frameworks for describing the universe, they say. It is the theory of general relativity, which describes the behavior of gravity as a continuous field known as space-time. And quantum mechanics uses the mathematics of probability to explain the behavior of discrete particles.
For a unified theory of quantum gravity that is universally applicable, we need to find a way to somehow reconcile these two contradictory theories.
This is where black holes come into play, perhaps the strangest and most extreme objects in the universe. These massive objects are incredibly dense, so within a certain distance from the black hole’s center of mass, the cosmic velocity is not high enough for them to escape. Not even the speed of light.
that distance, Change Depending on the mass of the black hole, it is called the event horizon. Once an object crosses that boundary, no important information about its fate comes back, so we can only imagine what will happen. However, in 1974, Stephen Hawking proposed that interruptions in quantum fluctuations caused by the event horizon produce a type of radiation that is very similar to thermal radiation.
If this Hawking radiation exists, it is still too weak for us to detect. We’ll probably never be able to extract it from the hissing static of the universe. However, by creating black hole analogues in a laboratory setting, we can study their properties.
This has been done before, but in November 2022, a team led by Lotte Mertens from the University of Amsterdam in the Netherlands tried something new.
A one-dimensional chain of atoms acts as a pathway. Electrons “hop” from one location to another. By adjusting the likelihood of this hopping, physicists were able to make certain properties disappear, effectively creating a kind of event horizon that interferes with the wave-like nature of electrons.
The effects of this false event horizon produced a temperature increase consistent with theoretical expectations for comparable black hole systems, the researchers said. But only if part of the chain extends beyond the event horizon.
This could mean that entanglement of particles across the event horizon helps generate Hawking radiation.
The simulated Hawking radiation was only thermal for a certain range of Hopf amplitudes, under a simulation that began by mimicking a type of spacetime that could be considered “flat.” This suggests that Hawking radiation may only be thermal if there are changes in the gravitational distortion of spacetime and within a range of circumstances.
What this means for quantum gravity is unclear, but the model provides a way to study the appearance of Hawking radiation in an environment unaffected by the violent dynamics of black hole formation. It is also very simple, so it can be used in a wide range of experimental settings, the researchers said.
“This could open up the field to explore aspects of fundamental quantum mechanics, along with gravity and curved spacetime in various condensed matter environments.” the researchers wrote.
This study physical review study.
A version of this article was first published in November 2022.