Physics
Oblique view of a superconducting double-contact

Casimir Effect Observed Photon Light from a Vacuum



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Oblique view of a superconducting double-contact
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"Casimir Effect Observed Photon Light from a Vacuum"
Caption: Oblique view of a superconducting double-contact
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Image by: Herbertweidner
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Scientists achieved a miracle in the physics laboratory—using a quantum mirror they created photons from a vacuum.

The "Casimir Effect," first predicted more than four decades ago, has been achieved by scientists at Chalmers University of Technology

SQUID and virtual particles

Using a superconducting quantum interference device (SQUID) that acts as an electronic mirror with quantum qualities sensitized to magnetic fields, Christopher Wilson and his fellow researchers nudged photons from a virtual state into reality within a vacuum.

To achieve this bit of laboratory magic, the SQUID had to vary the direction of the magnetic field vibrating it up to a remarkable one-quarter of light speed. To reach that rate, the field had to change billions of times every second.

The research, "Observation of the dynamical Casimir effect in a superconducting circuit" published by the journal Nature, proves one of the major contentions of quantum physics: a vacuum is not empty.

Vacuums contain quantum events, matter and energy can fluctuate between existence and non-existence. If a particle or wave is virtual, meaning it has the potential to exist, it can become real (pulled into this physical world) and stabilized here as either energy or matter.

SQUID used exotic quantum technology to almost literally pull photons into existence from a vacuum.

The dynamical Casimir effect

It's a process that was first predicted by a physicist named Moore. During 1970, he postulated that if a mirror could spin at a rate close to the speed of light it might be possible to bounce virtual photons off it and propel them into reality. The attainment of Moore's hypothesis is referred to as the dynamical Casimir effect and the Chalmers team witnessed it for the first time in history.
 
Quoted in the Chalmers press release, Per Delsing, the Professor of Experimental Physics at Chalmers said, “Since it’s not possible to get a mirror to move fast enough, we’ve developed another method for achieving the same effect. Instead of varying the physical distance to a mirror, we've varied the electrical distance to an electrical short circuit that acts as a mirror for microwaves.”

In theory it should work. When they built it and ran it, it did work—not something that's always accomplished in a physics experiment.

Let there be light

When photons began appearing—literally from the nothingness of quantum space, the team was ready to measure them with a special apparatus. As Per Delsing explained, "The result was that photons appeared in pairs from the vacuum, which we were able to measure in the form of microwave radiation. We were also able to establish that the radiation had precisely the same properties that quantum theory says it should have when photons appear in pairs in this way."

Exciting virtual photons into existence and creating light from virtual nothingness takes relatively little energy. But the team is confident that larger, more energetic particles with mass can also be coaxed into existence.

"In principle, one could also create other particles from vacuum, such as electrons or protons, but that would require a lot more energy," he said.

Vacuum fluctuations and the creation of energy and matter from the quantum is what's driving the theory of dark energy. It may also account for the Corliss effect that's the basis for research into so-called zero point energy—the ability to draw infinite amounts of energy from the heart of a vacuum.

Sources

Chalmers press release: Chalmers scientists create light from vacuum

Light Created from a Vacuum: Casimir Effect Observed in Superconducting Circuit

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  • InfoBoxCallToAction ActionArrowhttp://www.chalmers.se/en/Pages/default.aspx
  • InfoBoxCallToAction ActionArrowhttp://www.nature.com/nature/journal/v479/n7373/full/nature10561.html
  • InfoBoxCallToAction ActionArrowhttp://www.chalmers.se/en/news/Pages/Chalmers-scientists-create-light-from-vacuum.aspx
  • InfoBoxCallToAction ActionArrowhttp://www.sciencedaily.com/releases/2011/11/111118133050.htm