Every time you take a step, the space itself glows with soft warmth.
Called the Fuling-Davis-Unru effect (or sometimes just the Unru effect if you’re pressed by time), this ominous glow of radiation coming out of the vacuum is similar to Hawking’s mysterious radiation, which is thought to surround black holes. .
Only in this case is it a product of acceleration, not gravity.
Don’t you feel it? There is a good reason for this. You will have to move at an impossible speed to feel even the faintest rays of Unruh.
For now, the effect remains a purely theoretical phenomenon, far beyond our ability to measure. But that may soon change with the discovery of researchers at the University of Waterloo in Canada and the Massachusetts Institute of Technology (MIT).
Returning to the basics, they demonstrated that there may be a way to stimulate the effect of Unruh so that it can be studied directly in less extreme conditions.
In an unexpected turn, they may have revealed the secret of making matter invisible.
The real reward, however, would be the discovery of new foundations in experiments that aim to bring together two powerful but incompatible theories in physics, one that describes how particles behave and the other that spans the curve of space and time.
“The theory of general relativity and the theory of quantum mechanics are still somewhat at odds at the moment, but there must be a unifying theory that describes how things work in the universe,” said Achim Kempf, a mathematician at the University of Waterloo.
“We were looking for a way to combine these two great theories, and this work is helping us get closer by opening up opportunities to test new theories against experiments.”
The Unruh effect is right on the border of quantum laws and general relativity.
According to quantum physics, an atom that sits all alone in a vacuum will have to wait for the incoming photon to pass through the electromagnetic field and give its electrons a shake before it can be considered illuminated.
If we look at relativity, there is a way to cheat. Simply by accelerating, an atom can experience even the smallest oscillations in the surrounding electromagnetic field, such as low-energy photons transformed by a kind of Doppler effect.
This interaction between the relative experience of waves in a quantum field and the shaking of the electrons of the atom relies on a shared moment in their frequencies. All quantum effects that do not rely on time are usually ignored, given on paper, they tend to balance in the long run.
Together with colleagues Vivisek Sudhir and Barbara Soda, Kempf showed that when an atom accelerates, these usually insignificant conditions become much more significant and may in fact take on the role of dominant effects.
By tickling an atom in the right way, such as with a powerful laser, they have shown that it is possible to use these alternative interactions to make moving atoms experience the Unruh effect without the need for large accelerations.
As a bonus, the team also found that with the right trajectory, an accelerating atom can become transparent to incoming light, effectively suppressing its ability to absorb or emit certain photons.
Leaving aside science fiction applications, by identifying ways to influence the ability of the accelerating atom to engage with waves in a vacuum, we may be able to invent new ways to discover where quantum physics and general relativity give way to new ones. theoretical framework.
“For more than 40 years, experiments have been hampered by the inability to study the interface between quantum mechanics and gravity,” said Sudhir, a physicist at MIT.
“Here we have a viable option to explore this interface in the laboratory. If we can understand some of these big issues, it could change everything.”
This study is published in the Physical Review Letters.
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