Quantum teleportation is a process in which the quantum state of one particle, such as the spin or polarization, is transferred to another distant particle without physically moving the particle itself. While the term "teleportation" may evoke images of instantaneous transportation, quantum teleportation does not involve the actual transfer of matter or energy.
In the realm of quantum mechanics, teleportation has been experimentally achieved at the quantum level. The first experimental demonstration of quantum teleportation was carried out in 1997 by a team of researchers led by Anton Zeilinger, using pairs of entangled photons. Since then, numerous experiments have been conducted to refine and extend the capabilities of quantum teleportation.
In these experiments, the process typically involves three key elements: an entangled pair of particles (usually photons), a particle to be teleported (often called the "input" or "source" particle), and a distant particle (the "target" particle). The entangled pair acts as a resource that enables the transfer of quantum information.
The process of quantum teleportation involves performing measurements on the input particle and the entangled pair, followed by classical communication of the measurement results. Based on these results, operations are performed on the target particle to reproduce the quantum state of the input particle, achieving teleportation.
Over the years, experiments have successfully teleported quantum states between various physical systems, including photons, ions, and even solid-state systems. Teleportation has been achieved over varying distances, from a few meters in laboratory setups to hundreds of kilometers using fiber-optic networks.
It's important to note that quantum teleportation does not violate the principles of causality or allow for faster-than-light communication, as the teleportation process still relies on classical communication of information. While quantum teleportation holds promise for applications in quantum communication and quantum computing, it currently remains a specialized technique within the domain of quantum physics research.