Faster-than-light (FTL) travel or communication has long been a dream of science fiction writers but for almost as long as FTL has been imagined it has been assumed to be theoretically impossible. However, recent experiments have shown that the light-speed barrier can be broken through the strange phenomenon of quantum tunnelling. I lack the space to explain quantum tunnelling in detail, but suffice it to say that it’s a way for particles to cross seemingly impassable barriers by doing the quantum equivalent of facing the other way and walking backwards.
The concept of quantum tunnelling has been an accepted part of quantum mechanics almost since its inception. George Gamow used it to explain the phenomenon of alpha decay (the effect that causes radium to glow in the dark so eerily) as early as 1920, but it was not until 1955 that Wigner and Eisenbud (winners of the 1956 AAAS prize for ‘Silliest Names in a Joint-Submission Paper (Physics)’) discovered a peculiar effect. Under certain circumstances, while the particle is engaged in ‘tunnelling’ through the barrier, it will take a fixed amount of time to penetrate the barrier regardless of how wide the barrier is! As this time-interval can be extremely short (of the order of 10-15 seconds), it is perfectly possible to construct a barrier that is so wide that the poor particle has to pick its skirts up and exceed the speed of light to cross it. This theory caused a few bobbed adam’s-apples among the ranks of theoretical physicists as, post-Einstein, the speed of light was widely regarded to be a limit. However, after a bit of soul-searching the physicists found a get-out clause: they hum-ed and ha-ed and deemed that it was OK for a particle to exceed the speed of light as long as causality was not violated.
Causality? Ah, right. Sorry. Causality is an important concept in Einsteinian physics. The principal of causality implies that, for a given frame of reference, the ‘happening-ness’ of a given distant event cannot travel towards you faster than c, the speed of light. So you can’t be aware of something having happened until a time that is L/c seconds later, where L is the distance. However, it’s apparently OK to have things quantum tunnelling their way towards you from far and wide at many multiples of c just so long as you can have no idea where they’re from, where they’re going or when they’re going to turn up. A bit like Reading Transport buses on a wet Tuesday, in fact. So, since you can’t know anything about these particles then no-one can transmit information faster-than-light: if anyone ever managed to successfully beam, say, Mozart’s 40th Symphony at some absurd speed like 4.7c then the entire fabric of space-time would fall down around our ears or, worse, Einstein would have been proved wrong. And we can’t have that.
So, imagine the furore that ensued when in 1995 a German physicist, Günther Nimtz, and his team claimed they had indeed successfully transmitted Mozart’s 40th Symphony at a transition-speed of 4.7c over a distance of 11.4cm. History shows that the fabric of space-time did not proceed to fall down around our ears, but the alternative consequence was too much for 20th century physics to bear. Nimtz’s many critics strove mightily to find fault in his equipment, scientific method and finally, desperately, his musical taste, falling back on the argument that since they personally found Mozart rather boring then his 40th Symphony couldn’t be considered ‘information’. The controversy raged far and wide, consuming entire University physics departments in its fiery intensity.
We felt it was our duty to Science to resolve this controversy. And what else could we use to help us but that most valuable and useful of experimental animals, the humble hamster? In fact, anybody who has spent any time with a hamster knows that the wee beasties have considerable talents in this direction already. If you have ever proudly ushered a visitor in to admire Hammy only to be confronted by an amorphous heap of wood-shavings then you will be well aware that hamsters are highly adept at tunnelling. Furthermore, if you have ever left the cage door open inadvertently then you will have encountered the strange phenomenon whereby your little furball disappears inextricably under the sofa exactly 0.63 seconds after you spot it no matter how far apart the cage and sofa are. Re-read the second paragraph and tell me if that doesn’t sound familiar.
However, it was felt that the hamster was insufficiently quantum for our purposes, so we decided to attempt to cross it with the only other quantum creature known to science, Schrödinger’s Cat. The experiment was partially successful: the hybrid thus engendered had the intriguing property of only ever moving a fixed distance (11.4cm, coincidentally), but in a varying amount of time. The time, and thus the speed, of transition varied widely. Some days it hardly seemed to move at all, other days we were kept awake long into the night by tiny sonic booms. The cat-hamster (Catster? Ham?) proved totally useless for our purposes, but it purred so we kept it.
Reluctantly, we abandoned the attempt to breed a fully quantum-enabled hamster and fell back on the time-honoured physics tradition of constructing obscenely expensive and arcane mechanisms in secret caverns under the Swiss Alps. Since we had determined that our hamsters were insufficiently quantum to initiate tunnelling without aid we had to develop a mechanism to scan the hamster molecule-by-molecule, deconstruct it, quantumly-tunnel it across a barrier (which we made 11.4cm wide for sentimental reasons) and reconstruct it on the other side. Obviously the design of this equipment is trivial: such machines are being thrown together by bright geeky college kids and wild-haired DeLorean-driving scientists across the United States every day, so I leave the principles and techniques as an exercise for the reader. After a few hundred partially-successful trial runs (which furnished the project director’s wife with a nice hamster-fur coat) the equipment was ready for use.
The next problem we had to solve was how to prove that information could be transmitted faster-than-light across the quantum barrier. We reasoned that if the hamster lost its memory in the transition then it would be proof that information could not be transmitted faster-than-light. However, even when fully compos mentis hamsters are in the habit of wandering around aimlessly and bumping into things, so we decided we needed an objective method of gauging information-loss. We discovered that by using love, praise, and only a moderate amount of high-tension electricity we could train a hamster to squeak a coded message. If it could still squeak that message after being superluminally transmitted then it would prove that information could be transmitted at FTL speeds.
We then entered into a depressing few months of unsuccessful experimentation. Thousands of hamsters were carefully trained and inserted into the tunnelling machine but they all proved completely unable to squeak coherently thereafter. Finally we gave up and decided to have a party instead. As the party began to warm up one of the researchers unveiled his prize specimen, a female hamster which, ignorant of hamster anatomy, he had named ‘Wolfgang’. In Nimtz’s honour - and by using prodigious amounts of love, praise and voltage - he had trained Wolfgang to squeak Mozart’s 40th Symphony from beginning to end. This feat caused us much merriment and, as a climax to the party, higher mental functions completely nullified by a vicious Swiss liqueur called gentiane, we inserted Wolfgang into the device and hit the switch. Imagine our surprise when she emerged from the other end note-perfect! Instantly sobered, we ran her through the machine again and again, with no negative effect on her performance whatsoever, although she had a tendency to go flat on the high notes when tired.
This completely revivified the research. We sent out for more hamsters and tried other classical tunes. Bach, Beethoven, Stockhausen: no joy. We tried the Beatles, the Spice Girls, James Brown, King Crimson: not a squeak. We tried all of Mozart’s other 40 symphonies: silence. It seemed the only tune that a hamster would remember after being transmitted faster-than-light was Mozart’s 40th Symphony! Finally, after much careful research, we scientifically determined it to be ‘one of those things’ and decided to explore a further intriguing line of research.
What was the new line of research? Well, if you think quantum tunnelling is spooky, consider this: once you’ve got the tunnelling sorted it is theoretically possible to transmit particles back in time! It’s a bit complicated as it requires two transmitters moving in opposite directions at close to the speed of light, and someone sitting on a convenient planet to kick things off. You also need some pretty precise timing, a bit like a relativistic trapeze-act, but it can, theoretically, be done. And that was good enough for us. We used up the last centime of our EU grant-money, sent a couple of ion-powered space capsules into long, looping orbits around Jupiter, strapped Wolfgang into the machine and pressed the big red button.
She never came back. Or, rather, she never appeared a split-second before we sent her off. We think we probably turned the power up too high.
And that was how things stood until last week, when I received a strange missive from Professor Rawlins of Exeter University, who is aware of our researches. It contained, without comment, an excerpt from Mozart’s diaries, which I am quoting here with permission:
‘July 24th 1788: Got up a little late today: 2pm. My darling Stanzi was visiting her parents so I felt I did not need to make the effort. Played a little, but the themes I tried did not please me. I was on the point of going out to steal Signore Salieri’s milk when I espied a strange little creature hiding under the fortepiano. At first I assumed it was a rat and made to kill it, but, as I approached it, it began squeaking, as if my violent and threatening demeanour were some kind of cue. And what a tune it did squeak! Soaring melodies, worthy of me at my best! I lost no time in copying it down: all it needs is a little tidying and orchestration, and I think I shall do that tomorrow. In fact, as I write this, a mischievous thought occurs to me: I shall publish this little rat-tune as my own and see if anybody notices! I will wager that cloth-ear Salieri will not… Felt much better after this, so decided to visit the opera and heckle.’
We have carefully considered this new evidence and have reached the following conclusions:
- We definitely misjudged the power and actually hurled Wolfgang 210 years into the past.
- Mozart copied the 40th Symphony from our hamster.
- Therefore, Mozart’s 40th Symphony does not violate causality because it could never have existed without our quantum tunnelling experiments.
- Therefore, assuming Einstein was right all along, the only information that can ever be transmitted faster-than-light is Mozart’s 40th Symphony
- Therefore it does not, strictly, constitute information as the observer at the other end will always know what to expect.
- Also, any aliens conducting FTL experiments had better like Mozart, because that’s all they’ll ever be able to send as well.
So, there you have it. The next time you get round to the last-but-one in your expensive boxed-set of Mozart symphonies, don’t forget to raise a glass to the memory of Wolfgang, the greatest of all FTL hamsters. We would like to think that the Mozart family continued to care for her throughout a long and happy life, but bearing in mind this was the 18th century, we suspect the cat probably got her.