Sometimes the word “minus” times “minus” is a “plus” not only in mathematics, but also in the broader sciences. Take, for example, the very impressive and somewhat ambiguous professional article recently published by two physicists from the University of Edinburgh. On the scientific publishing site by Arxiv† In it, they tackle one very difficult thing – communication with intelligent alien civilizations – with another very difficult thing: cosmic quantum communication.
Well, back to the gas. Aliens, Quantum: What, How and Why?
Let’s start with the first hard thing: communicating with intelligent aliens. This is a very complicated task and so unlikely to succeed that many serious scientists consider it to be the most enjoyable pastime. At the same time, the reward if it succeeds will be enormous. It will prove that there is more life elsewhere than just a dirty lichen or something. That there are beings with whom you can have a conversation, who, like humanity, can see and understand the universe.
Hence, for example, SETI (Looking for extraterrestrial intelligence?) by searching using radio telescopes for messages from these intelligent civilizations. Although for the time being this has not worked, even after decades of research.
Perhaps not so strange, as some alien investigators believe. We live in a remote corner of an unimaginably large world, so you must be very lucky to hear Radio Alien by chance. Even if you are looking specifically.
But: we may be looking for the wrong signals. Because if alien civilizations start sending us messages, as the physicists suggest in their article, it might not be boring old-fashioned radio messages, but modern, X-ray-encoded quantum messages.
This is a second confusing thing: quantum communication, which is communication that uses wacky quantum forces to travel long distances without chipping. First of all, the “superposition”, which ensures that the quantum version of a bit, a qubit, is not only “0” or “1”, but can also be “0” and “1” simultaneously. and “entanglement,” which allows two qubits to communicate in such a way that they also feel each other’s influence at different ends of the universe.
Exploit both superpowers, and enable quantum communication. More than a thousand kilometers have now been achieved in China, which is the world record at the moment.
But, as physicists write: something like this is also possible at cosmic distances, up to tens of light years. The space around us is so empty that you can shoot particles of light with quantum forces through it without the risk of them bumping into something else along the way.
If aliens did indeed send out such quantum messages, we should be able to easily identify them as evidence of extraterrestrial intelligence. Unlike radio signals, which are also emitted by ordinary cosmic bodies without life, there is no known natural source for quantum X-rays.
Thus ‘minus’ times ‘minus’ here too – hopefully, perhaps, who knows, in the end – is ‘plus’ again.