Physics

15 trillion quantum entangled atoms make a record-breaking hot mess

15 trillion quantum entangled ...
An artist's impression of a cloud of hot atoms with quantum entanglement links (yellow/blue lines) connecting them
An artist's impression of a cloud of hot atoms with quantum entanglement links (yellow/blue lines) connecting them
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An artist's impression of a cloud of hot atoms with quantum entanglement links (yellow/blue lines) connecting them
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An artist's impression of a cloud of hot atoms with quantum entanglement links (yellow/blue lines) connecting them
The researchers heated rubidium metal and nitrogen gas to high temperatures to create a cloud of hot rubidium atoms that were quantum entangled
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The researchers heated rubidium metal and nitrogen gas to high temperatures to create a cloud of hot rubidium atoms that were quantum entangled

Quantum entanglement is a phenomenon that’s as bizarre as it is fragile. Entangled particles are thought to lose this inexplicable link when exposed to outside factors. But now, physicists have managed to produce hot clouds of trillions of entangled atoms, breaking quantity records and showing that entanglement isn’t as fragile as previously thought.

Pairs or groups of particles can become so intertwined that measuring the state of one will instantly change properties of the others, no matter how far apart they are. That sounds weird enough already, but the implications threaten to undo our entire understanding of physics. Somehow, information seems to be sent between them much faster than the speed of light, which is meant to be impossible.

Einstein himself didn’t believe it at first, deriding it as “spooky action at a distance” and instead blaming hidden variables. But decades of experiments have shown that quantum entanglement is indeed the real deal, and we’re already starting to exploit the phenomenon for new technologies, such as faster and more secure communication networks.

But one problem is that this link between particles is very fickle, so tiny disturbances from other particles or events can disentangle them. To prevent that from happening, most experiments and technologies that use quantum entanglement can only work at ultracold temperatures – close to absolute zero (-273.15 °C, -459.67 °F). At that point almost all movement stops, so there’s no disturbances to break the link.

Of course, that extreme cooling isn’t practical for commercial or consumer products, so scientists are trying to find ways to make quantum entanglement possible at warmer temperatures. Past research has succeeded at room temperature, and now it’s been done under even hotter conditions.

The new study was conducted by researchers at ICFO, Hangzhou Dianzi University, and the Technical University of Valencia. The team mixed rubidium metal with nitrogen gas, and heated it up to 176.9 °C (350.3 °F). At that temperature, the metal vaporizes, causing free rubidium atoms to float around the chamber. There they become entangled with each other, and the team can measure that entanglement by shining a laser through the gas.

The researchers observed as many as 15 trillion entangled atoms in the gas, which they say is about 100 times more than any other experiment. Interestingly, the entanglement seemed to link atoms that aren’t necessarily close to each other – between any given pair are thousands of other atoms, each with their own partners.

The researchers heated rubidium metal and nitrogen gas to high temperatures to create a cloud of hot rubidium atoms that were quantum entangled
The researchers heated rubidium metal and nitrogen gas to high temperatures to create a cloud of hot rubidium atoms that were quantum entangled

But the most intriguing part of the study is that the entangled state might not be as fragile as scientists had thought. In this hot, energetic gas, the atoms are constantly bouncing off each other, yet the quantum connections remain. It seems that the collisions don’t destroy the entanglement but pass it along to other atoms.

“If we stop the measurement, the entanglement remains for about one millisecond, which means that 1,000 times per second a new batch of 15 trillion atoms is being entangled,” says Jia Kong, first author of the study. “And you must think that 1 ms is a very long time for the atoms, long enough for about 50 random collisions to occur. This clearly shows that the entanglement is not destroyed by these random events. This is maybe the most surprising result of the work.”

The team says that this discovery could help in a few fields. In particular, magnetoencephalography, which is a magnetic brain imaging technique that uses these kinds of gases to detect extremely faint magnetic signals from brain activity.

“This result is surprising, a real departure from what everyone expects of entanglement,” says Morgan Mitchell, corresponding author of the study. “We hope that this kind of giant entangled state will lead to better sensor performance in applications ranging from brain imaging to self-driving cars to searches for dark matter.”

The research was published in the journal Nature Communications.

Source: ICFO

11 comments
Brian M
Usually (and unfortunately!) have a view on most things but when it comes to Quantum entanglement I defer to the wisdom of Einstein its just too dam 'spooky'!

Spooky or not the fact that something is occurring faster than light and combined that with the mystery of dark matter/energy then its hinting at something being very wrong with our fundamental understanding of the universe.

Be interesting to see whether this less fragility of quantum entanglement will lead to further opportunities to investigate further this spookiness.
Vernon Miles Kerr
One would almost think that, if there is a God, he-she-or-it is trolling us. The deeper we go into physics the more questions arise. This being is probably laughing his-her-or-it's ass off right now.
notarichman
i'm confused! are more than a pair entangled? that could be useful. or just such as previously found, lots of pairs?
sidmehta
Entanglement can "change our entire understanding of physics". OK Mike what are the alternate theories that scientists think are possible?
CraigAllenCorson
Here's the problem I have with this entanglement thing. They say that measuring the state of particle A of an entangled pair will instantly change the state of particle B of that pair. How can they know the state of particle B before and after measuring the state of A, without measuring B's state and thus altering A? It makes no sense.
I guess that means that I understand quantum entanglement, then, because it's not supposed to make sense. But they also say that if you think that you understand it, that means you don't. 😵😵🤪🤪🥴🥴
christopher
@sidmehta alternate theories include multiverses and non-linear time off the top of my head.

@CraigAllenCorson time is your answer - measure A first (helps if you send A and B in opposite directions out to mirrors). This whole spooky thing is all based on violations of our assumption that time is linear in one direction, which appears not to be the case. There's plenty of experiments around now that show it is possible to change the past of atoms, even as many as hundreds at once.
mediabeing
One more time!!

I, for one, welcome the mighty Vapor Mind in all its quantum wonderfulness.
Spare me and my parrot, please. Thanks.
MemoriaTechnica
@ Brian M: I'm no physicist, however, one potential explanation that pops into my woefully uninformed mind is the possibility the entangled particles existing in a trans-dimensional state. i.e. Their "connection" passes through a higher dimension, not unlike traveling through a wormhole, so in fact no "information" is moving faster than light.

@ notarichman: A "pair" by definition is two. So you have two quantum entangled particles in each pair. Now if I understood the article correctly, previously, studies have show the entangled state to be "fragile"; i.e. they are easily disrupted and the entanglement is "broken". So in the past, by cooling them down to near absolute zero, they did the scientific equivalent of putting them in a room alone so as not to be disturbed. However, this latest study demonstrates that they can exist in much more "crowded" and hotter environments without disrupting their entangled state. This is good news since it opens up the possibilities for usage in a much wider range of situations.

@ CraigAllenCorson: Both particles in an entangled pair *always* do the exact opposite of each other , and they also have "spins" that can be measured and manipulated. So if you know your spinning particle A in a clockwise direction, you can know for certain particle B is rotating in a counter-clockwise direction. So spin A and measure B.

That said, there are many out there who know far more about the subject than I, so if I got any of this wrong, please do chime in.
Nobody
How do they know that all 15 trillion quantum entangled atoms were indeed entangled??? The claim seems rather incredulous to me.
thx1138
No thing (nothing) can travel faster than the speed of light. But information is not a physical thing so the law does not apply to information. Thus information has no speed limit.