Have scientists created light from nothing? If true, this experiment will provide one of the most excitingly unusual proofs of quantum mechanics in recent history.
A team of scientists at the Chalmers University of Technology in Gothenburg Sweden published a paper in 2011 talking about this bizarre experiment. Of course, since we are dealing with quantum mechanics, you can expect the reality of the situation to be very peculiar. This experiment is centered around the principle that empty space isn’t really empty. For the record, since I’m talking about quantum mechanics, I don’t mean ‘outer-space’ empty, I mean empty empty; a complete vacuum, space with absolutely nothing inhabiting it.
Here, we dive into the concept of quantum foam (also known as spacetime foam). Long, complicated story short, in quantum theory, empty space is teeming with activity as particles pop in and out of existence, in a way that can conceptually be thought of as a foamy lather. It isn’t uncommon for scientists to refer to these particles as being ‘virtual’ since they exist for only a brief moment of time. Don’t let the name fool you though, these particles can have an affect on the macro side of the size spectrum—an effect that can be measured in the lab and is known as the Casimir effect.
If scientists put two plates extraordinarily close to each other (but not touching), they can create a vacuum effect between the plates as they limit the size of particles that can exist. Here, scientists create what can be thought of as a low pressure zone between the plates, and the outside energy of space pushes them together.
Now some things get interesting. Scientists have predicted that you can achieve a similar effect simply by moving a single mirror very quickly. Here, scientists theorize that the mirror will absorb energy from ‘virtual photons’, then re-emit that same energy as ‘real photons’—as always, there is a catch. This mirror needs to move through a vacuum at speeds close to that of light. Naturally, this is extremely tough to do.
This is where researchers pull out SQUID, but instead of the aquatic beast, they are usually referring to a Superconducting Quantum Interface Device. This type of device is very sensitive to magnetic fields that, when attached to a circuit, acts just like a mirror. The Chalmers team then passed a magnetic field through the SQUID and abruptly switched the direction of the field several billion times a second which produced a wiggling effect in the SQUID, which caused it to wiggle at approximately five percent the speed of light.
What happened next can only be described as astonishing. Using this method, the research team claims they were able to ‘shake loose’ microwave photons which were emitted at approximately half the frequency of the wiggling wire. All in all, exactly what they would expect to see in a foamy universe.
The experiment is currently up for peer-review, so it hasn’t been confirmed yet. The research team has declined to speak to different publications about the experiment because it has yet to be verified. So, for now, we wait. To close with my favorite quote of the day, spoken by John Pendry, who works as a theoretical physicist at the Imperial College in London (he was not involved in the study), he said, while talking about the possibility of this experiment standing up to scrutiny, “Work in this area stirs considerable passion in the breasts of physicists.”