Physicists Work Out Way to See ‘Unruh Effect’ Elusive in Lab

Physicists Work Out Way to See 'Unruh Effect' Elusive in Lab
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A group of physicists said discovered two properties of an accelerating substance that they believe could make a type of radiation that had never been seen before visible. Newly described properties mean that observation of the radiation – called the Unruh effect – can occur in a bench-top laboratory experiment.

In theory, a ridiculous amount of acceleration is required for the Unruh effect to appear in nature.and since it can only be seen from the perspective of an object accelerating in a vacuum, it is essentially impossible to see. But thanks to recent advances, it may be possible to witness the Unruh effect in a laboratory experiment.

In a new study, a team of scientists describes two previously unknown aspects of the quantum field, which may mean that the Unruh effect can be directly observed. The first is that affect can be stimulated, meaning that a normally weak affect can be induced to become more visible under certain conditions. The second phenomenon is that a sufficiently excited accelerator atom can become transparent. It was a group study has been published this spring in Physical Review Letters.

The Unruh effect (or Fulling-Davies-Unruh effect, so named for the physicists who first proposed its existence in the 1970s) is a phenomenon predicted under quantum field theory that states that an entity (whether a particle or a spacecraft) ) accelerating in a vacuum will glow – although this glow will not sparkle.t visican be done nor does any external observer accelerate in a vacuum.

“Transparency with the acceleration means that it makes the Unruh effect detector transparent to everyday transitions because of the nature of its motion,” Barbara Shoda, a physicist at the University of Waterloo and lead author of the study, said in a video call. via Gizmodo. Just as Hawking radiation is emitted when black holes’ gravity pulls on particles, the Unruh effect is emitted by objects accelerating through space.

There are several reasons why the Unruh effect has never been directly observed. First, a ridiculous amount of linear acceleration is required for the effect to occur; To reach a temperature of 1 kelvin, at which point an accelerating observer will see a flash, the observer would have to speed uphorse 100 quintillion square meters per second. The glow of the Unruh effect is heat; If an object accelerates faster, the temperature of the glow it will be hotter.

Previous methods for observing the Unruh effect has been proposed. But this The team thinks they have an attractive chance of observing an effect thanks to their findings on the properties of the quantum field.

“We would like to build a specific experiment that can unambiguously detect the Unruh effect and then provide a platform to study various related aspects,” said Vivisek Sudhir, a physicist at MIT and co-author of the latest work. “Unambiguous is the key adjective here: in a particle accelerator, it’s actually bunches of particles that are being accelerated, making it very difficult to tease out the extremely subtle Unruh effect among the various interactions between the particles in the bunch.”

“In a sense,” Sudhir concluded, “we need to measure more precisely the properties of well-defined single accelerated particles, which are not designed for particle accelerators.”

Hawking radiation is predicted to be emitted by black holes like these two captured by the Event Horizon Telescope.

Hawking radiation is predicted to be emitted by black holes like these two captured by the Event Horizon Telescope.
Image: EHT Cooperation

The essence of their proposed experiment is to stimulate the Unruh effect in the laboratory using an atom as an Unruh effect detector. By blasting an atom with photons, the team will raise the particle to a higher energy state, and its acceleration-induced transparency will silence the particle against any everyday noise that would mask the presence of the Unruh effect.

By stimulating the particle with a laser, Shoda said, “You increase the probability of seeing the Unruh effect, and that probability increases with the number of photons in the field.” “And that number can be huge depending on how powerful your laser is. In other words, because researchers can shoot a particle with quadrillion photons, they increase the probability of the Unruh effect by 15 orders of magnitude.

Because the Unruh effect is similar to Hawking radiation in many ways, the researchers believe that the two quantum field properties they recently described can be used to stimulate Hawking radiation and imply the existence of gravitational transparency. Since Hawking radiation has never been observed, it may be a step towards uncovering the Unruh effect to better understand the theoretical glow around black holes.

Of course, if the Unruh effect can’t be observed directly in the laboratory, these findings don’t mean much – the researchers’ next step. Exactly when Although this experiment will be conducted, it remains to be seen.

More: Laboratory Black Hole Proves Stephen Hawking Right

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