We recently received the following email question:
… I really wanted a burger from White Castle after watching Harold and Kumar, but sadly we don’t have White Castles in California. So I got to wondering… is teleportation possible? Are there any laws of physics that it defies or have we just not obtained the technology yet?
Thanks! Meg W. Colliefohnia
Thanks for the interesting question Meg.
For me, teleportation inevitably brings to mind Star Trek style transporters so I’m going to tackle this question initially from that angle. From a pure information and energy standpoint, transporting someone from a ship in orbit to the surface of a planet would require technologies that can handle literally unimaginable amounts of information and energies.
Consider one estimate of the information contained in a person in terms of position and orientation of all the atoms to the limit of the uncertainty principle. Physicist Laurence Krauss puts that at 10 to the 28 kilobits. That’s something like 12 billion billion million megabytes. This has been compared to 10 cm high 1Terabyte hard drives stacked up 100 light-years high. Even with compression we’d probably end up with a light year of hard drives. That’s a lot of hard drives.
As you might imagine, just writing this amount of data to those hard drives would take non-trivial amounts of time. Even a relative speedy 20 giga-bytes a second write-speed would take 7 times the age of the universe…and you thought that filling your computer with porn took some time.
Add to all that the fact that turning a human into energy to beam to it’s destination would require handling the energy a one gigaton nuke would release. That’s one billion tons of tnt. Imagine the OSHA regulations for that.
The other way to look at this and probably what Meg was thinking was the very real quantum teleportation experiments that seem to crop up in the news every few years. This is a fascinating area of research with many potential applications. Many of these experiments are real teleportation too since the process creates a duplicate of something and destroys the original in the process. So this isn’t just a fancy replicator we’re talking about.
The key phenomenon that allows for quantum teleportation as we know it is called entanglement. This is one of the most mind-boggling aspects of quantum mechanics, which is saying something considering that quantum mechanics is practically synonymous with the term “mind-boggling”. The gist of entanglement is that two particles can interact with each other or can be created from the same process in such a way that their quantum states become linked. While this link exists you can no longer adequately describe one particle without reference to the other. This means that even if they’re separated by a billion light years, they can still in some ways be considered one object.
This Star Trek analogy just occurred to me. There was an episode in which the transporter malfunctioned and produced a good Kirk and an evil Kirk. It couldn’t make two good Kirks or two evil ones. One good one and one evil one are both required to adequately describe Captain Kirk and this would be true even if one was on Rigel 5 and the other was….um…..really far away.
One way entanglement manifests itself is not good and evil but in terms of particle spin. In some situations, one entangled particle has to be spin up and the other has to be spin down. Before measurement, both particles exist as a superposition of both spin up and spin down at the same time. If one is determined to be spin up; the other would have to be spin down even though its spin wasn’t determined until the first particle was measured potentially light years away. How does the particle know it had to be spin down?
This apparent superluminal communication when entangled particles are measured is what Einstein famously called spooky action at a distance. Remember though that Einstein’s faster than light dictum has not been invalidated. No information is breaking the speed limit and therefore no communication can be done using this process. The states of the particles are still random. You can’t encode a signal into a process that produces random results. The fact remains however that there seems to be an influence of sorts that is propagating faster than light. In fact, some recent tests declare that if the speed is not instantaneous, it is no less than 10,000 times the speed of light. Reality is so counter-intuitive at the quantum level that we can’t discount the possibility that we are operating under a false premise. We are assuming after all that something is propagating faster than light even if we can’t use it for communication. Perhaps this idea of something propagating between entangled particles is itself a false assumption. On the other hand maybe something is propagating but it requires other dimensions or time travel to accomplish its task.
Dr Terence Rudolph of Imperial College, London, has said that “any theory that tries to explain quantum entanglement… will need to be very spooky – spookier, perhaps, than quantum mechanics itself”.
Who needs paranormal piffle when you’ve got this stuff to think about?
ok..back to teleportation.
The quantum teleportation process that scientists use usually follows a process like this:
Entangle two particles A & B
Entangle particle B to a third particle C
Perform a specific measurement of A changing its state.
Particle C can then have its quantum state be identical to A before its measurement.
That’s it in a nutshell. Particle A has had its quantum state transferred to another particle at an arbitrary distance.
This process demands however 3 important things:
2-Specially prepared initial quantum states.
3-Complete separation from the environment.
This last point is especially important since any interaction with an external environment produces decoherence which changes the quantum state the particle is in, collapsing the entanglement and preventing the teleportation.
People are about as different as possible from these objects and so are White castle hamburgers. We are composed of quantum objects that are all flying around and interacting destroying any entanglements that may have arisen. We are walking bags of decoherence.
Physicist Lawrence Krauss offers an analogy on this:
“A single particle like a photon can tunnel through a barrier, disappearing on one side and appearing on the other…We can’t walk through walls. People are a complex, classical system [of particles].”
So what’s the answer to Meg’s question? Can it ever be done?
I’ll defer to a couple of experts to guide us for this one.
“Some day we may figure out ways to make classical systems behave quantum mechanically. But there’s a big difference in declaring something possible and then making it practical. Transporting anything other than a particle is extremely implausible.”
Michio Kaku: Theoretical Physicist and host of the Science channel’s new show-Visions of the Future:
“There is nothing in principle to prevent us from teleporting an actual person (assuming we accept the risks), but the technical problems are staggering” it could be centuries or longer before everyday objects are teleported, if it’s possible at all”
The bottom line appears that we may someday be able to teleport White Castle hamburgers (and people) but the technology required is so mind numbingly complicated that it may never be practical. Kaku thinks it may take centuries.
My guess is that we may see it but it will likely require post-singularity technology (don’t get me started).