What does quantum teleportation mean?

Quantum teleportation is a technique for transmitting quantum information from a source location to a destination located at a certain distance. Regardless of the distance separating them, two "entangled" particles are able to transmit the information they share.

What does quantum teleportation mean?
Quantum teleportation. Image by Darkmoon_Art from Pixabay

One of the recurring and most fascinating themes in science fiction is the teleportation of human beings, which would allow us, as in the "Star Trek" movie series, to disappear in one place and appear in another. Surely this topic, along with that of time travel, appeals to us because of its enormous potential to satisfy our need to travel and explore.

Although the teleportation method seen in "Star Trek" is impossible, since, according to the law of conservation of matter and energy, an object cannot disappear in one place and appear in another without a means of transporting it, a variant could consist of scanning the structure of the object, to know its state in the smallest detail, and then sending this information to another point to reconstruct an identical copy there using different materials.

Until a couple of decades ago, scientists thought that teleportation could never become a reality. This is because the most detailed information that can be obtained about an object must be obtained by using the branch of physics that describes the behavior of atoms and molecules, called quantum physics. The impossibility of teleportation was because, according to the laws of quantum physics, the mere fact of observing an object modifies its quantum state, through what is technically called "the collapse of its wave function".

However, in 1993 a group of physicists published a paper describing a variant of teleportation that would be allowed by quantum physics. This variant, which they called quantum teleportation, makes use of a property of some systems at the atomic level in which two particles that are separated behave like the same because they are "intertwined at the quantum level". It is curious that Albert Einstein, who was one of the founders of quantum physics, never accepted that quantum entangled systems could exist.

It was not until experiments could be done to confront quantum physics with Einstein's ideas, in the 1980s, that it was proven that in this aspect Einstein was wrong, and that quantum physics does indeed predict implausible behaviors of light particles, called photons, and atoms. To give an example, it is as if, apart from the fact that particles at the atomic level can pass through walls or be in two places at the same time when a particle that is quantum entangled with another is measured for a property, the other particle modifies that same property at the same time, even though it is separated by an enormous distance.

In this situation, you may be wondering whether or not teleportation is possible. As it turns out, once the mechanism of quantum teleportation was proposed, several groups of scientists devoted themselves to do experiments with very simple systems, formed by a pair of particles, to prove or disprove it. It was with surprise that it was possible to prove its viability, first for distances of the order of one meter and nowadays already of hundreds of kilometers.

We can therefore affirm that quantum teleportation is a reality and that it may have applications that even surpass current science fiction, for example in the construction of "quantum computers", much faster than current computers. However, maintaining a quantum entangled system is extremely difficult for systems of just a few atoms, so doing so for macroscopic objects containing quadrillions -- a quadrillion is one followed by 24 zeros -- of atoms requires technological advances that we do not yet have and that seems very distant.

Quantum is the smallest value that a physical quantity can accept. For example, the smallest moment of the momentum is h / 2, where h is the Planck constant. According to quantum mechanics, the corresponding quantities can only be multiples of this quantum. The smallest value of a physical quantity, the smallest amount of energy. Quantum of light, electromagnetic field - photon.

Teleportation is the theoretical movement of material or energy from one point to another without physically crossing the space between them. It is a popular subject in science fiction literature, film, video games, and television.

Sources: University of Michoacan