Entanglement Can Occur at High Temperatures

Entanglement is a property that subatomic, elementary particles have, of being in instant contact with each other over massive distances. For example, if in a quantum system a particle is observed, and therefore has its properties established, the same thing happens to its pair, regardless of where the second one is located. In other words, some have called this phenomenon two particles sharing the same existence, whereas Albert Einstein called it “spooky action at a distance”. So far, physicists have believed that this state can only be obtained at very low temperatures, near absolute zero.

This quantum state is as fragile as it is amazing. Any interactions between the quantum system exhibiting it and the environment around and it's gone. This is one of the main reasons why experts are having such a hard time isolating and studying it. They need to setup up the conditions for their observations in such a manner that everything else surrounding the quantum entangled particles does not affect the pair. This can only be done by conducting studies near absolute zero. At such low temperatures, the environment becomes benign, and the sought-for effects can be evidenced.

Another possible solution is to study entanglement in elementary particles that do not interact with their surroundings, such as photons, the basic components of light. Any other circumstance and the environment exerts a nefarious situation on the quantum system, destroying it. It would appear that the fundamental limit to the thermal energies at which entanglement can be at use is comparable to very low temperatures, Technology Review reports. But Spanish researchers at the University of the Balearic Islands, led by expert Fernando Galve, show that by using something called a “squeezed state,” this limit can be increased considerably.

The team reveals that, by constantly squeezing a quantum system, the temperature range at which it maintains its properties, including entanglement, increases considerably. Furthermore, they also found that the state can be maintained, which means that the finding could actually be of significant practical use. This type of systems can now be held stable at temperatures of around 50 degrees Kelvin (-223 degrees Celsius), which is a considerable improvement from the 4K systems that were used before. “We believe this to be a huge experimental step,” they say in a paper published in the journal arXiv.