Teleportation is the hypothetical transfer of matter or energy from one point to another without traversing the physical space between them. It is a common subject in science fiction literature and in other popular culture. Teleportation is often paired with time travel, being that the travelling between the two points takes an unknown period of time, sometimes being immediate.

There is no known physical mechanism that would allow for teleportation. Frequently appearing scientific papers and media articles with the term teleportation typically report on so-called "quantum teleportation", a scheme for information transfer which, due to the no-communication theorem, still would not allow for faster-than-light communication.

Quantum teleportation is distinct from regular teleportation, as it does not transfer matter from one place to another, but rather transmits the information necessary to prepare a (microscopic) target system in the same quantum state as the source system. The scheme was named quantum “teleportation”, because certain properties of the source system are recreated in the target system without any apparent information carrier propagating between the two.

In many cases, such as normal matter at room temperature, the exact quantum state of a system is irrelevant for any practical purpose (because it fluctuates rapidly anyway, it "decoheres"), and the necessary information to recreate the system is classical. In those cases, quantum teleportation may be replaced by the simple transmission of classical information, such as radio communication.

 

Note:   The above text is excerpted from the Wikipedia article Teleportation, which has been released under the GNU Free Documentation License.