Back in 1997, physicists performed an extraordinary experiment that will be forever remembered by researchers and Star Trek fans alike. In this demonstration, the team transported photons from one point in the universe to another without sending them through the space in between — the first successful teleportation in history.

Teleportation is the transfer of the information that describes one object to another object elsewhere in space. In effect, this second object takes on the identity of the first. A more precise description of the team’s experiment with photons is that they transferred the quantum information that describes the polarisation state of one photon to another photon.

Still impressive but not quite the teleportation of the entire photon, which has multiple quantum properties. All of these need to be teleported to recreate it exactly.

Since then, this kind of teleportation has become routine in quantum optics labs all over the world but always with the same limitation. All these experiments involve the transfer of a single quantum property. Nobody has ever found a way to transmit the multiple quantum properties of a single object at the same time and thereby truly teleport it.

Until now. Today, Xi-Lin Wang and buddies at the University of Science and Technology of China in Hefei say they have done just that. The team have worked out how to teleport two quantum properties of a single photon to another photon at the same time — the first time this has ever been done. The work is an important stepping stone towards the ultimate goal of teleporting complex objects such as atoms and small molecules in their entirety.

Most standard teleportation experiments focus on the teleportation of a photon’s polarisation, which is oriented either vertically or horizontally and so is easy to measure. A more complex form of polarisation occurs when the polarisation rotates about the beam axis as the photon propagates.

This is known as circular polarisation and as a result, the photon has a kind of angular momentum known as spin angular momentum that can also be teleported.

Photons can have another type of angular momentum determined by their movement through space. This so-called orbital angular momentum is another a quantum property that can be teleported.

It is these properties— the spin angular momentum and the orbital angular momentum — that Xi-Lin and co have teleported together for the first time.

So how did they do it? The secret ingredient in any teleportation experiment is entanglement, the strange quantum link in which two particles share the same existence despite being in different locations.

This shared existence means sharing the same quantum state. It is this sharing between particle 1 and 2 that allows a quantum state to be transmitted from one point in space to another.

Until now, this sharing has always involved a single quantum state such as polarisation. The trick that Xi-Lin and co have perfected is creating entangled photons which share a hybrid quantum state that includes both the spin angular momentum and the orbital angular momentum.

They then use these entangled photons as the medium through which to teleport the properties of a third photon. They then measure the final state to ensure that the spin and orbital angular momentum have indeed been teleported accurately.

This final step is tricky because there 16 different hybrid states that the photon can be in and the team have to unambiguously distinguish between them all to tell whether the original hybrid state has been accurately teleported. The ability to do this is the main experimental advance.

The result is that Xi-Lin and co say they are able to teleport both the spin angular momentum and the orbital angular momentum of a single photon at the same time. “We demonstrate the first quantum teleportation of multiple properties of a single quantum particle,” they say.

And they say there is no reason why their technique cannot be extended to other properties as well. A single photon has multiple properties including its frequency and momentum as well as the spin and orbital angular momentum. So a true teleportation of the entire photon would include all these properties.

Xi-Lin and co say the work shows this is possible in principle. “Our methods can in principle be generalized to more degrees of freedom, for instance, involving the photon’s momentum, time and frequency.”

That’s interesting work that could have important implications elsewhere. For example, quantum cryptography is only possible between detectors that have been carefully aligned to accurately distinguish horizontal and vertical polarisation. The new technique allows alignment-free quantum cryptography.

Beyond that is the potential to teleport more complex quantum systems such as atoms and molecules. And after molecules, who knows. Small viruses perhaps?

Ref: arxiv.org/abs/1409.7769 : Quantum Teleportation Of Multiple Properties Of A Single Quantum Particle