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20 April 2012 @ 03:29 am
Article in Scientific American Blog about CA  
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Quantum Casimir Effect Inspires Indie Filmmakers

By Jennifer Ouellette | April 19, 2012|

The Internet is filled with surprising things. Jen-Luc Piquant stumbled across a fascinating independent short film project the other day, called Casimir Effect — the brainchlid of UK filmmakers Gabriel Strange and Lydia Wood, and starring Torchwood‘s Gareth David Lloyd as the male lead. It’s still unfinished, with fundraising efforts ongoing, but the premise seems pretty promising.

Casimir Effect tells the story of Dr. Alice Sharpe (Zoe Mills), a quantum physicist in the year 2101 who has been studying the potential use of wormholes for transportation — through both space and time. She becomes the first person to travel through time, except things don’t quite go as planned. Instead of traveling seven days into the future, she finds herself 100 years in the future.

Naturally a temporal paradox ensues, forcing Alice to travel next into the past and the year 2050, where her future true love, Bob Cameron (played by Lloyd), is conducting the first experiments on the Casimir effect and its potential use in stabilizing wormholes. Alice must choose to be with the man she loves — thereby risking the collapse of the space-time continuum — or sacrifice her own happiness to, well, save the entire universe. Sometimes love really sucks.

The film might be pure fiction, but its premise is founded in real physics. The 19th-century Serbian inventor Nikola Tesla believed the vacuum held enormous reservoirs of energy, sufficient to revolutionize human society if we could only devise a means of harnessing it. Tesla was highly eccentric – he ended his days impoverished and with questionable sanity – but his intuition about there being energy in the vacuum turned out to be true.

See, empty space isn’t really empty. It roils and boils with quantum fluctuations, occasionally spitting out pairs of “virtual” elementary particles and antiparticles. These virtual particles annihilate and disappear back into the quantum vacuum so quickly that the apparent violation of energy conservation incurred by their creation can’t be observed directly.

So how do we know they exist? There is indirect evidence in a phenomenon known as the Casimir effect, named after Henrik Casimir, the Dutch physicist who discovered it in 1933.

Casimir received his PhD at the University of Leiden in 1931, under Paul Ehrenfest, with a thesis on the quantum mechanics of a rigid spinning body and molecular rotation. During that time, he also spent 18 months in Copenhagen, working with Niels Bohr. Then he worked as an assistant in Zurich to Wolfgang Pauli before accepting a professorship at Leiden University. His research centered on heat and electrical conduction.

His time at Leiden was interrupted by the outbreak of World War II; the university was shut down in 1942. So Casimir moved to the Philips Research Laboratories in Eindhoven. It was here that he became intrigued by the possibility of measuring the van der Walls force between two parallel metallic plates. Two years later, he and a student, Dik Polder, conceived of an experiment to do just that.

Normally two uncharged parallel metal plates would remain stationary because there is no electromagnetic charge to exert a force to pull them together (or push them apart). But Casimir found that if the plates are close enough, there is still a tiny attractive force between them.

Because the parallel plates are so close together, virtual particle pairs can’t easily come between the plates, so there are more pairs popping into existence around the exterior of plates than there are between them. The imbalance creates an inward force from the outside that pushes the plates together slightly. The smaller the separation between the plates, the fewer virtual pairs can get between them, and the greater the force of the inward attraction.

If we could figure out a way to harvest just the antiparticle of a virtual pair, we would have a built-in source of negative energy in the quantum vacuum. Okay, sure, that’s a pretty big “if.” Even if we could find a way to harvest this negative energy, it isn’t remotely sufficient for wormhole purposes.

A wormhole only one meter wide would require negative energy equivalent to the total energy produced by our sun over roughly 10 billion years, yet the Casimir effect is quite small, equal to the weight of 1/30,000 of an ant, so it could only create a wormhole smaller than an atom, making travel through it impractical at best. We would need to find a means of amplifying that energy many times over before it would become strong enough to hold open a macroscopic wormhole.

Frankly, the energy contained in the quantum vacuum isn’t nearly as much as Tesla supposed, when one converts it into macroscale units of measurement. Release the energy stored in one cubic meter of the quantum vacuum — about the size of a small dumpster — and you’d only get about one ten-billionth of a joule. That’s not enough to light a 10-watt bulb. That hardly seems sufficient to open a wormhole of the sort featured in the film.

Caltech physicist Kip Thorne famously devised a wormhole model based on negative energy. He proposed creating two identical chambers, each of which contains two parallel metal plates separated by a very small gap. The electrical field created by the plates via the Casimir effect creates a tear in space-time, so that the chambers become the two “mouths” of a connecting wormhole.

Then one chamber is placed on a rocket ship and accelerated to near the speed of light. Since time is moving at different rates in each chamber due to relativistic time dilation, the two chambers become desynchronized. They are still connected by the wormhole, yet they exist in different times. Time has passed more slowly in the accelerating chamber, so a person in the earthbound chamber could step through the wormhole and be hurtled into the past.

A similar effect could be achieved by connecting a wormhole between the earth and something very heavy, like a neutron star. This also sets up a time difference between the two ends, since mass warps space and time. A clock on the surface of a very dense neutron star would run about 30% slower than it does on earth.

Naturally, there’s catch. Quantum vacuum fluctuations would almost certainly destroy such a wormhole before it could be used as a portal, thanks to what amounts to a devastating feedback loop.

Virtual particles pass through the wormhole to the past. But then they must travel forward through space and time, eventually re-entering the wormhole and traveling back to the past again, in a never-ending cycle. Eventually the radiation becomes strong enough to destroy anything that tries to pass through to the other side. In the end, it would even destroy the wormhole.

The obstacles to building big swirly wormholes have proven insurmountable so far. The search continues for a feasible wormhole model that might one day serve as a portal to other universes, or to other points in time. In the meantime, we have intriguing flights of fancy via films like Casimir Effect.
i_bananasi_bananas on May 21st, 2012 06:01 pm (UTC)
Could you add a LJ-cut to this post please? (After the 2nd paragraph would be fine)

Thanks for posting
Dairwendan Mirthmakerdairwendan on May 23rd, 2012 06:16 am (UTC)
Done! Sorry about that!