Aliens could communicate through a quantum internet in the Milky Way

By them astrophysicists from the University of Edinburgh, Arjun Berera and Jaime Calderón-Figueroa, recently published in the famous magazine Physical review D an article that would undoubtedly have caught the attention of the founding members of the concepts behind the Seti program, e.g. Carl Sagan. The publication is available free of charge at arXiv and it delves into the question of whether a technologically advanced civilization could not use a technology from quantum information theory, namely the teleportation of a quantum state, to communicate with other members of The blue chain according to the title of the former president of Seti-France’s work, Albert Ducros.

The question arises all the more that if the quantum computer revolution leads to some of the dreams of its pioneers, a technologically advanced civilization could only use quantum computers accurately communicate with each other thanks to the EPR effect behind the concept of quantum teleportation. We assume we could pass on much more information via quantum teleportation only with waves radio classics. On Earth, we also seek to develop a kindInternet quantum using beams laser.

Quantum teleportation for dummies

Let’s make a few reminders about quantum teleportation by going back to what Futura had already explained on this topic.

It all started in 1993, then physicist Charles Bennett and his colleagues (including Gilles Brassard and Claude Crépeau) are working on IBM published an article in which they suggested one protocol experimental to allow teleportation of quantum states. Four years later, the Austrian Anton Zeilinger published in Nature an article announcing that he, along with other researchers, had managed to implement Bennett’s ideas for quantum teleportation.

Of course, the performance and especially the name of the phenomenon immediately triggered the enthusiasm of the series’ fans. star trek, who sees the hope of making it one of the biggest dreams in science fiction. Unfortunately, there is little chance of a day with this quantum phenomenon of seeing equivalents of Mr. Spock and Captain Kirk disappear from the surface of pandora or a superjord to teleport back inside Enterprise.

The reason is that in the experiments made by physicists, only a quantum state is teleported, therefore information is irrelevant. In addition, the system physical original rental information is destroyed. At best, one clone complete, memory and state of consciousness included, of one of the characters of star trek could eventually be rebuilt aboard the Enterprise, but the original would be dead.

Quantum teleportation in itself is based on the phenomenon of quantum entanglements theoretically discovered by Einstein and Schrödinger in the 1930’s. It is this phenomenon that is at the heart of the famous EHR paradox, the existence of which was confirmed in 1982 by Alain Aspekt and his colleagues.

Capsule produced for the show What has become of the discoveries of the past, broadcast on Canal Savoir. This excerpt traces the development of a discovery by Gilles Brassard (University of Montreal) and Claude Crépeau (McGill University), selected from the 10 discoveries from 1993 of Quebec Science : quantum teleportation. © Quebec Research Fund

When two particles are quantum filtered, certain physical quantities of one of the two particles are determined when measured on another. The effect appears to be immediate, and if Alice on Earth makes a measurement on one of the particles entangled with that of Bob by thousands oflight yearswill Bob have measurement results on his own particle, which will depend on Alice, as if a signal had propagated from Alice to Bob much faster than light from the experiments performed, but which do not prove that the effect is really immediate.

But even though there are correlations between the two particles that are transluminal, it is impossible to make a phone that would communicate faster than light in this way.

We can still use a quantum state that carries a lot of information that would be transferred to Alice’s particle, by performing certain measurements, Alice would then teleport the quantum state and all the information to Bob’s particle.

But Bob could not extract the information encoded in his particle by exposing it to specific measurements without knowing what the results of Alice’s own measurements were.

If Alice, for example, used a number of pairs of photons entangled laser to transmit a quantum state, it will, for example, have to send the results of its measurements to Bob using radio waves. Therefore, we can not communicate faster than light between starsalthough it is suspected that the amount of transferable information would be much higher when working with quantum computers associated with quantum teleportation.

Let us now make a few reminders about the Seti program and its history.

Seti on the trail of lasers

One of the motivations knows Carl Saganwhen he helped develop the program Search for extraterrestrial intelligence, was trying to figure out if we had a chance to survive XXe and XXIe centuries. Specifically, Seti’s original goal was to discover the signals of an extraterrestrial civilization with a radio telescope and if possible determine if these signals contained a message to our destination … And to answer them.

The Cold War was in full swing in the last century, and the proliferation of nuclear weapons did not bode well. Today spectrum of nuclear war has moved away. But the consequences of global warming and the scarcity of natural resources that accompany our overpopulated and irrational world has not completely driven it out. The discovery of one or more ET civilizations could give us confidence in a future that seems very dark if we are to believe the famous Meadows reports predictions.

The best way to discover and get in touch with a technologically advanced ET civilization may not be by using radio telescopes. The means would be in projects that consist of trying to detect emissions from ET civilizations in the form oflaser pulseswhether they are the by-product of interstellar solar propulsion techniques, such as those in the project Breakthrough Starshot, or real attempts at interstellar communication. The idea that aliens may prefer to communicate over interplanetary and even interstellar distances using lasers is old. It is already formulated by Schwartz and Townes in 1961, a year after Townes invented the laser, and two years after Cocconi and Morrison proposed the basic concept of the Seti program.

Some pictures of LaserSeti. To get a fairly accurate French translation, click on the white rectangle at the bottom right. The English subtitles were then to be displayed. Then click on the nut to the right of the rectangle, then on “Subtitles” and finally on “Automatically translate”. Select “French”. © Seti Institute

We are now almost ready to understand the work of Arjun Berera and Jaime Calderón-Figueroa.

We have already made quantum teleportation between Earth and a satellite in space, the Chinese have achieved a remarkable achievement in recent years on this subject.. To begin with, they used one laser diode whose photons were wrapped in a non-linear optical device and sent out into space to test ideas for the planetary quantum internet of the future.

One of the benefits of sending photons into space is that they cross quicklyatmosphere terrestrial to enter the vacuum of space. It turns out, however, that just as in the case of computers, the problem of decoherence must be solved with a quantum internet. In fact, the quantum state carried by photons is fragile and can be degraded by the environment they pass through, limiting the range of information transfer.

The two astrophysicists therefore asked themselves the question of how much entangled photons were sent, e.g. from Earth towards one exoplanet around Proxima Centauri, could faithfully teleport information. More generally, what would be the prospect of greater interstellar distances in The Milky Way.

They thus took into accountabsorption light by gas and dust, disturbances from plasma particles and cosmic raysup to the influence of gravity stars, photons of cosmic radiation or Sun.

Remarkably, there would be no real problem and by operating with photons within X-rays we could reach a distance of several million light-years, even a quantum internet that could be intergalactic.

Specifically, in order to demonstrate the existence of a transmission of information by quantum teleportation of ET origin, it would be necessary to find a dual signal simultaneously, for example a laser beam in the visible as those seeking to detect the members of LaserSetiassociated with a radio signal which would provide the means for deciphering the quantum state transmitted by laser photons.

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