It's a Quantum World Record: 15 Trillion Smokin' Hot Atoms Entangled

Scientists have set a world record 15 trillion quantum entangled atoms. And while the record is big news—this is many times greater than any previous number—so is the way they achieved it.

To entangle all the atoms, the scientists used strong heat in an alkaline vapor cloud. That’s against popular wisdom about cooling with entanglement, and it opens new avenues for research and applications.

“In many quantum technology implementations, strong cooling and precise controls are required to prevent entropy—whether from the environment or from noise in classical parameters—from destroying quantum coherence,” the researchers explain in their paper. And instead, they describe plans to put atoms in a high-temperature, high-entropy environment.

At first, this sounds a little bit like deciding to travel from New York to Los Angeles by flying around the entire rest of the world. Why would you bother?

But there are technologies that use high temperatures to get better and different results. The scientists explain:


“Notably, vapor-phase spin-exchange-relaxation-free (SERF) techniques are used for magnetometry, rotation sensing, and searches for physics beyond the standard model, and give unprecedented sensitivity. Whether entanglement can be generated, survive, and be observed in such a high entropy environment is a challenging open question.”

To conduct the experiment, the scientists blasted an enclosed amount of radioactive rubidium gas with a laser probe. Like in a fusion reactor, the reactive gas is contained by a magnetic field. “Here, we study the nature of spin entanglement in this hot, strongly-interacting atomic medium, using techniques of direct relevance to extreme sensing,” they explain, meaning the experiment is structured to have results that can translate directly into the applications this team imagines.

High temperature is relative here, at 450 Kelvin, which is about 300 degrees Fahrenheit. Compare that with nuclear fusion, which takes place beginning at over 10,000 degrees. But it’s a million times hotter than the usual temperatures for quantum entanglement on anything like this scale. That means the technology could be used in situations where extreme cooling isn’t practical, but low “high temperatures” are.

And the researchers observed surprises even once the warm entanglement began. “The spin squeezing and thus the entanglement persist far longer than the spin-thermalization time of the vapor; any given entanglement bond is passed many times from atom to atom before decohering,” they explain.

The strong local reactions they predicted could derail the entanglement ended up preserving it and spreading it instead. The warm mass of entangled atoms held together. The researchers conclude:

“The results show that high temperatures and strong random interactions need not destroy many-body quantum coherence that collective measurement can produce very complex entangled states, and that the hot, strongly-interacting media now in use for extreme atomic sensing are well suited for sensing beyond the standard quantum limit.”

And, they say, the next step is to use atoms like this to enhance our sensing ability to detect magnetic waves at even the lowest and tiniest frequencies.

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