Are Aliens Using Stars To Communicate?

An advanced alien civilization could modify the light coming off of stars in order to communicate across enormous distances, according to a preprint paper published last week by Imperial College London quantum physicist Terry Rudolph.

The idea is that aliens may use entangled photons from various stars to send messages that appear to be random blinking to bystanders, and while this is pure speculation, it is technically conceivable in terms of physics. 


Rudolph writes that they’ve shown that “free-space diffraction of photons distributes highly useful entanglement. Quantum Entanglement occurs when two or more particles link up in a certain way: No matter how far apart they are, observations of one of the entangled particles can automatically reveal information about the other entangled particles, and any action taken on one of these particles will always have an impact on the others in the entangled system.

Receivers of the propagating modes — how radio signals move from a sending antenna to a receiving antenna — may perform distributed quantum computations using just linear optics and photon counting. While distributed computing necessitates traditional communication between receivers, much like standard measurement-based computation, this communication is based on entirely random outcomes and hence might be confused with noise.

But how does this tie with the possibility of us actually spying on alien conversations whenever we look at the sky? To make things a bit clearer, Rudolf’s theory is predicated on the idea that a cautious civilization could “hide their photonic entanglement dispersion by using the thermal light already being emitted by the different stars they visit.”

This would necessitate knowing the number of photons in the modes they’ve chosen to employ, which would also require performing a quantum non-demolition measurement of the photon number. “Because the thermal light they are measuring is diagonal in the number basis even this process can be rendered in principle indiscernible to those of us excluded from the conversation,” Rudolf wrote.

The thermal density matrix is unperturbed by the QND
measurement, as it is diagonal in this basis. Using this entanglement (for quantum computing, or quantum secret sharing,
or quantum data hiding, or quantum key distribution – or whatever you think aliens are up to) relies on classical communication of measurement outcomes between the receiving nodes.
One may hope, therefore, that we could detect the presence of
said aliens by looking for that communication. Unfortunately
for those of us who would like to listen in, similar to a one-way
computation on qubits, the local measurement outcomes –
and therefore messages that need to be communicated – are
themselves indistinguishable from thermal noise.
The upshot is that when we look to the stars and see only
thermal radiation we typically conclude the universe is empty.
But perhaps, riding in the correlations of that radiation, the
universe is actually bathed in alien chatter and other forms
of distributed quantum information processing.

The Bent Light Discovery uses stars to communicate with Extraterrestrial Life


“It is the Macroscopic Quantum Realm that will unlock the secrets to Consciousness, Quantum Technologies, and Extraterrestrial Communication.”

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