Chemistry depends on heat.

Atoms or molecules bounce around randomly, collide, and form other molecules. At higher temperatures, atoms collide more and the rate at which atoms become molecules increases. Below a certain temperature, the reaction won't happen at all.

But something very weird happens at the lowest temperatures. In this extreme cold, there is essentially no heat energy, yet chemical reactions happen faster than they do at high temperatures.

The phenomenon is called quantum superchemistry. And it was finally demonstrated last year, more than 20 years after physicists first proposed it.

In that experiment, University of Chicago physicist Cheng Chin and colleagues coaxed a group of cesium atoms at just a few nanokelvin into the same quantum state. Amazingly, each atom did not interact separately. Instead, 100,000 atoms reacted as one, almost instantaneously.

The first demonstration of this weird process has opened a window for scientists to better understand how chemical reactions operate in the strange realm of quantum mechanics, which governs the behavior of subatomic particles. It also may help to simulate quantum phenomena that classic computers struggle to model accurately, such as superconductivity.

But what happens after that, as with so many advances in research, is hard to predict. Chin, for one, has no plans to stop studying this strange form of chemistry.

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"No one knows how far we can go," Chin told Live Science. "It might take another 20 years. But nothing can stop us."

The term "superchemistry" was coined in 2000 to liken the phenomenon to other strange effects, like superconductivity and superfluidity, which emerge when large numbers of particles are in the same quantum state.

Unlike superconductivity or superfluidity, however, "'superchemistry' differs in that it is still barely realized, while these other phenomena have been extensively studied in experiments," Daniel Heinzen, lead author of the 2000 study and a physicist at the University of Texas at Austin, told Live Science in an email.

Heinzen and colleague Peter Drummond, who is now at the Swinburne University of Technology in Australia, were studying a special state of matter known as a Bose-Einstein condensate (BEC), in which atoms reach their lowest energy state and enter the same quantum state. In this regime, groups of atoms begin to act more like a single atom. At this small scale, particles can't be described as being in a given place or state. Rather, they have a probability of being in any given place or state, which is described by a mathematical equation known as the wave function.

In a BEC, just as Satyendra Nath Bose and Albert Einstein's work predicted, the individual wave functions of each atom become a single, collective wave function. Heinzen and Drummond realized that a group of particles with the same wave function is similar to a laser a group of photons, or packets of light, that have the same wavelength. Unlike with other light sources, the peaks and troughs of a laser's wave are aligned. This allows its photons to stay focused in a tight beam over long distances, or to be broken up into bursts as short as millionths of a billionth of a second.

Related: How do lasers work?

Similarly, Heinzen, Drummond and their colleagues showed mathematically that the atoms in a BEC should behave in ways other groups of atoms don't. Near absolute zero, where there is almost no heat energy, quantum superchemistry means the atoms in a BEC could convert, quickly and all together, to molecules: Atoms A would bond in a flash to form molecules of A2, and so forth.

The process would resemble a phase transition, Chin says, such as when liquid water freezes to ice. And, thanks to the quantum weirdness of these systems, the more atoms condensed in the BEC, the faster the reaction happens, Heinzen and Drummond's calculations predicted.

Heinzen and his research group tried to demonstrate the phenomenon with experiments for several years. But they never found convincing evidence that the effect was happening. "And then we kind of dropped it," Heinzen said.

While Heinzen abandoned the quest to demonstrate quantum superchemistry, others were still hunting for ways to turn the wild theory into experimental reality. One of them was Chin, who started working on quantum superchemistry almost immediately.

Chin was a doctoral student studying cesium atoms at cold temperatures when Heinzen and Drummond's superchemistry paper came out. "My research was totally derailed because of this new research," Chin told Live Science. He set out on what would become a 20-year quest to achieve quantum superchemistry in the lab.

It wasn't a straight path, and Chin sometimes took breaks from working toward quantum superchemistry. But he never abandoned his goal.

"Nobody knew if this was going to work out before it happened. But also nobody said it couldn't happen," he said.

After a decade of slow progress, in 2010, Chin and his colleagues figured out how to precisely tune magnetic fields onto a BEC to coax cesium atoms together to make Cs2 molecules.

"That provided the evidence of how to move forward," Chin said.

But to show quantum superchemistry was occurring, his team still needed better ways to cool and control ultracold molecules.

Nobody knew if this was going to work out before it happened. But also nobody said it couldn't happen.

Scientists typically use two techniques to push atoms and molecules to ultracold temperatures. First, lasers cool atoms to millionths of a kelvin above absolute zero. Atoms in the sample absorb photons from a laser tuned to very specific energy, thus reducing the atoms' momentum and the sample's temperature incrementally.

Next, they use evaporative cooling. The atoms in these experiments are trapped by laser light or magnetic fields. Scientists can adjust the traps to let the fastest and, therefore, hottest atoms escape. This process further cools the atoms to billionths of a kelvin, where quantum superchemistry is possible.

It was the second step that took Chin and his collaborators the longest to get right. For years, he had used bowl-shaped traps that pushed the atoms together in the middle, which raised the samples' temperature.

Six or seven years ago, his group began using a digital micromirror device to better control the shape of the trap. The result? Flat-bottomed traps, shaped something like petri dishes, where the atoms could spread out and stay ultracold.

Around 2020, Chin's group finally made a BEC of cesium molecules. They were some of the coldest molecules ever made, about ten-billionths of a degree above absolute zero. And while the team suspected quantum superchemistry had occurred, they didn't have proof.

That proof came three years later. By then, they had collected the evidence of two hallmarks of quantum superchemistry. First, the reaction was happening collectively, meaning many cesium atoms became cesium molecules at once. And second, it was reversible, meaning the atoms would become molecules, which would become atoms, and on and on.

For Chin, last year's experiments are just the beginning. They produced two-atom molecules using superchemistry. But Chin thinks three-atom molecules are within reach, and he's excited to see what else might be possible.

As is often the case in areas of fundamental research like this one, the experiments have raised new theoretical questions. For instance, in Heinzen and Drummond's theoretical quantum superchemistry system, more than half of all the atoms in a trap would convert into molecules and then go back again. But Chin's group observed that such a conversion happened only 20% of the time. Much is still to be understood to gain higher efficiencies, Chin said in an email.

Heinzen suspects collisions between molecules in the dense gas are to blame. Collisions could push molecules into different quantum states, knocking them out of the pool of condensed molecules. He and Drummond had not accounted for that possibility in their theory.

"It was obvious even from the beginning [that collisions were] going to be kind of a negative effect, but in 2000 we had no idea how big it would be," Heinzen said. "We just said, we're ignoring it because we don't know how big."

The experiments also revealed that three cesium atoms were frequently involved in forming a single Cs2 molecule (and leaving one Cs atom left over), which physicists call a three-body interaction. Previous predictions about quantum superchemistry did not include such interactions.

For Chin, that's a hint that he'll need to do some new experiments. If his group can design and perfect experiments to probe these many-body interactions, it could help elucidate the rules of quantum superchemistry.

Despite these open questions, many scientists view quantum superchemistry as a possible tool for better understanding chemical reactions in general. Atoms and molecules in a boiling beaker inhabit wide ranges of quantum states and interact in myriad ways that make them too complicated to study in fine detail experimentally. In contrast, atoms and very simple molecules in BECs are in precisely controlled, well-defined quantum states. So quantum superchemistry could be a way to study reactions in very fine detail.

"[It's] a very appealing regime in terms of advancing our fundamental understanding of chemistry," Waseem Bakr, a physicist at Princeton University who studies ultracold atoms and molecules, told Live Science.

Quantum superchemistry also has scientists excited because it provides precise control over molecular quantum states.

That could be useful for quantum simulation, a cousin of quantum computers. Typically, scientists simulate quantum systems on "classical" systems, such as conventional computers. But many processes, such as high-temperature superconduction, might be better modeled using quantum systems that are governed by the same quantum rules. Quantum superchemistry would give scientists a tool for producing molecules in specific quantum states that would enable those simulations, Bakr said.

Heinzen sees plenty of reasons for scientists to keep exploring the phenomenon he helped dream up more than 20 years ago. While the applications are little more than pipe dreams right now, history has shown that advances in fundamental science can sometimes lead to surprising applications down the road.

"It's not obvious right now," he said. "But it's still really worth doing."

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Inside the 20-year quest to unravel the bizarre realm of 'quantum superchemistry' - Livescience.com

Physicist Brian Cox takes us into the mind-bending world where quantum mechanics, black holes, and the future of computing converge.

In this interview, Cox shares the engineering challenges behind building quantum computers and the intricate dance of storing information in their notoriously delicate memory. However, black holes have an unexpected link to quantum information storage. Cox discusses how Planck units, holography, and redundancy could shape the future of computing.

It is a mind-expanding discussion that pushes the boundaries of our understanding. Even Cox says, Youre not meant to understand what Ive just said because I dont understand what Ive just said because nobody understands what Ive just said.

Welcome to the frontier where natures laws and technological innovation collide.

BRIAN COX:There's an engineering challenge in building quantum computers, which is how to store information in the memory of the quantum computer safely, robustly, because quantum computer memory is notoriously susceptible to any interference from the outside environment. If any of the environment in which the memory sits interacts with the memory in any way, then the information is destroyed.

And there are deep problems associated with the fact that you can't copy information in quantum mechanics, which is basically the way that your iPhone, or whatever it is, stores information and prevents errors entering into the memory of the computers that we're all familiar with; it's basically copying information. You can't do that in quantum mechanics. So it's a tremendous challenge.

Engineers have had to develop very clever algorithms and ways of trying to store information in quantum computer memory and build the memory such that it's resilient to errors. And it turns out that the solutions that are being proposed and explored look like the solutions that nature itself uses in building space and time from the quantum theory that lives on the boundary. It's really strange.

The remarkable thing for me is an intimate relationship between If we go back right to the beginning of the work on black holes in the 1970s, Jacob Bekenstein, the colleague of Stephen Hawking's actually, one of the first researchers to really begin working on black holes alongside greats like John Wheeler.

Bekenstein noticed in a simple calculation that you can answer the question, "How much information can a black hole store?" That's a strange thing to say because the model of a black hole is pure geometry, pure spacetime. Now, how does something store any information? You need some structure. You need atoms or something that can store bits of information. Well, turns out that you can calculate that a black hole stores in bits. The information content is equal to the surface area of the event horizon in square Planck units.

What's a Planck unit? It's a fundamental distance in the Universe that you can calculate by putting together things like the strength of gravity, Planck's constant, the speed of light. It's the smallest distance that we can talk about sensibly in physics as we understand it. The questions it raises: How is information stored? Why is the information content of a region of space equal to the surface area surrounding that region rather than the volume?

If I asked you, how much information can you store in your room, the room that you're sitting in now, just say it's a library, then you would say, "Well, it's to do with how many books I can fit in the room." But black holes seem to be telling us that there's something about the surface surrounding a region. This is the first glimpse, I think, of an idea called What is that?

So if you think about what a hologram is, at the very simplest level, it's a piece of film. But that piece of film contains all the information to make a three-dimensional image. It's the idea that there are different descriptions of our reality. There's one description, which is that we live in this space, the three dimensions of space, and time is a thing that ticks, and Einstein told us that they're kind of mixed up, but still you have this picture of space being this, right, the thing in which we exist.

There's an equivalent description for a very specific model called by a physicist called Maldacena, which is a dual theory that lives purely on the boundary of the space and the space itself in the interior of this region. So it's strongly suggestive that there's a deeper theory of our experience of the world, of space and time, that does not have space and time in it.

And that's one of the wonderful surprises that's really emerged from the study of black holes and the attempt to answer the very well-posed questions. I should say that the work done by Maldacena was purely mathematical. It wasn't framed in the study of black holes, although the questions ultimately seem to be intimately related.

So the study of black holes seems to be strongly suggesting that these ideas of holography, holographic universe, which came from a different region of physics, from trying to understand other things, those descriptions may be valid, maybe in some sense true. And it seems that we're beginning to glimpse an answer, at least in very simplified models- and that the information is stored on the boundary redundantly, which means that you can lose a bit of it and still fully specify the physics of the interior.

And it does seem that that's akin to, or similar to, the way that we will in the future encode information in the memory of quantum computers to protect them from errors. So I'm giving you an interpretation which, and there will be other people who have different interpretations, but it does seem that whatever this quantum theory is that underlies our reality, then there's some redundancy in the way the information is stored in that quantum theory. And it does seem that that's similar to the way that we will in the future encode information in the memory of quantum computers to protect them from errors,

And I just emphasize, you're not meant to understand what I've just said because I don't understand what I've just said because nobody understands what I've just said, right? We're catching glimpses of this theory, and that's where the research is at the moment- it's why it's tremendously exciting.

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A 7-minute guide to the relationship between quantum mechanics and black holes - Big Think

Department of Physics, Loyola University Chicago, Chicago, IL, USA

R. Abbasi

Deutsches Elektronen-Synchrotron DESY, Zeuthen, Germany

M. Ackermann,S. Athanasiadou,S. Blot,J. Brostean-Kaiser,L. Fischer,T. Karg,M. Kowalski,A. Kumar,N. Lad,C. Lagunas Gualda,S. Mechbal,R. Naab,J. Necker,T. Pernice,S. Reusch,C. Spiering,A. Trettin&J. van Santen

Department of Physics and Astronomy, University of Canterbury, Christchurch, New Zealand

J. Adams

Department of Physics and Wisconsin IceCube Particle Astrophysics Center, University of WisconsinMadison, Madison, WI, USA

S. K. Agarwalla,A. Balagopal V,M. Baricevic,V. Basu,J. Braun,D. Butterfield,S. Chattopadhyay,D. Chirkin,A. Desai,P. Desiati,J. C. Daz-Vlez,H. Dujmovic,M. A. DuVernois,H. Erpenbeck,K. Fang,S. Griffin,F. Halzen,K. Hanson,S. Hori,K. Hoshina,R. Hussain,M. Jacquart,A. Karle,M. Kauer,J. L. Kelley,A. Khatee Zathul,J. Krishnamoorthi,J. P. Lazar,L. Lu,J. Madsen,Y. Makino,S. Mancina,W. Marie Sainte,K. Meagher,R. Morse,M. Moulai,M. Nakos,V. ODell,J. Osborn,J. Peterson,A. Pizzuto,M. Prado Rodriguez,Z. Rechav,B. Riedel,I. Safa,P. Savina,M. Silva,R. Snihur,J. Thwaites,D. Tosi,A. K. Upadhyay,J. Vandenbroucke,J. Veitch-Michaelis,C. Wendt,E. Yildizci,T. Yuan,P. Zilberman&M. Zimmerman

Universit Libre de Bruxelles, Science Faculty, Brussels, Belgium

J. A. Aguilar,N. Chau,I. C. Mari,F. Schlter&S. Toscano

Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark

M. Ahlers,K. M. Groth,D. J. Koskinen,T. Kozynets,J. V. Mead,A. Sgaard&T. Stuttard

Department of Physics, TU Dortmund University, Dortmund, Germany

J. M. Alameddine,D. Elssser,P. Gutjahr,M. Hnnefeld,K. Hymon,L. Kardum,W. Rhode,T. Ruhe,J. Soedingrekso,J. Werthebach&L. Witthaus

Bartol Research Institute and Department of Physics and Astronomy, University of Delaware, Newark, DE, USA

N. M. Amin,S. N. Axani,P. A. Evenson,J. G. Gonzalez,R. Koirala,A. Leszczyska,A. Novikov,H. Pandya,E. N. Paudel,A. Rehman,F. G. Schrder,D. Seckel,T. Stanev,S. Tilav&S. Verpoest

Department of Physics, Marquette University, Milwaukee, WI, USA

K. Andeen&A. Vaidyanathan

Erlangen Centre for Astroparticle Physics, Friedrich-Alexander-Universitt Erlangen-Nrnberg, Erlangen, Germany

G. Anton,A. Domi,A. Eimer,S. Fiedlschuster,T. Glsenkamp,C. Haack,U. Katz,C. Kopper,M. Rongen,S. Schindler,J. Schneider,L. Schumacher&G. Wrede

Department of Physics and Laboratory for Particle Physics and Cosmology, Harvard University, Cambridge, MA, USA

C. Argelles,J. Y. Book,K. Carloni,D. Delgado,A. Garcia,M. Jin,N. Kamp,J. P. Lazar,I. Martinez-Soler,I. Safa,B. Skrzypek,W. G. Thompson,A. Y. Wen&P. Zhelnin

Department of Physics and Astronomy, University of Utah, Salt Lake City, UT, USA

Y. Ashida,M. Jeong&C. Rott

III. Physikalisches Institut, RWTH Aachen University, Aachen, Germany

L. Ausborm,C. Benning,J. Bttcher,L. Brusa,S. Deng,S. El Mentawi,P. Frst,E. Ganster,O. Gries,C. Gnther,L. Halve,M. Handt,J. Huler,J. Hermannsgabner,L. Heuermann,O. Janik,S. Latseva,A. Noell,S. Philippen,A. Rifaie,J. Savelberg,M. Schaufel,L. Schlickmann,P. Soldin,M. Thiesmeyer,C. H. Wiebusch&A. Wolf

Physics Department, South Dakota School of Mines and Technology, Rapid City, SD, USA

X. Bai,L. Paul&M. Plum

Department of Physics and Astronomy, University of California, Irvine, CA, USA

S. W. Barwick

Department of Physics, University of California, Berkeley, CA, USA

R. Bay,S. R. Klein,Y. Lyu&S. Robertson

Department of Astronomy, Ohio State University, Columbus, OH, USA

J. J. Beatty,A. Connolly&W. Luszczak

Department of Physics and Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, OH, USA

J. J. Beatty,A. Connolly,W. Luszczak,A. Medina&M. Stamatikos

Fakultt fr Physik & Astronomie, Ruhr-Universitt Bochum, Bochum, Germany

J. Becker Tjus,A. Franckowiak,J. Hellrung,E. Kun,M. Lincetto,L. Merten,P. Reichherzer&G. Sommani

Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden

J. Beise,O. Botner,A. Coleman,C. Glaser,T. Glsenkamp,A. Hallgren,N. Heyer,E. OSullivan,C. Prez de los Heros,A. Pontn&N. Valtonen-Mattila

Physik-department, Technische Universitt Mnchen, Garching, Germany

C. Bellenghi,P. Eller,M. Ha Minh,M. Karl,T. Kontrimas,E. Manao,R. Orsoe,E. Resconi,L. Ruohan,C. Spannfellner,A. Terliuk&M. Wolf

Department of Physics and Astronomy, University of Rochester, Rochester, NY, USA

S. BenZvi&S. Griswold

Department of Physics, University of Maryland, College Park, MD, USA

D. Berley,E. Blaufuss,B. A. Clark,J. Evans,K. L. Fan,S. J. Gray,K. D. Hoffman,M. J. Larson,A. Olivas,R. Procter-Murphy,T. Schmidt,S. Sclafani,G. W. Sullivan&A. Vijai

Dipartimento di Fisica e Astronomia Galileo Galilei, Universit Degli Studi di Padova, Padova, Italy

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Department of Physics and Astronomy, University of Kansas, Lawrence, KS, USA

D. Z. Besson,M. Seikh&R. Young

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F. Bontempo,R. Engel,A. Haungs,W. Hou,T. Huber,D. Kang,P. Koundal,T. Mukherjee,P. Sampathkumar,H. Schieler,F. G. Schrder,R. Turcotte,M. Venugopal,A. Weindl&M. Weyrauch

Institute of Physics, University of Mainz, Mainz, Germany

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School of Physics and Center for Relativistic Astrophysics, Georgia Institute of Technology, Atlanta, GA, USA

B. Brinson,C. Chen,P. Dave,I. Taboada&C. F. Tung

Department of Physics, University of Adelaide, Adelaide, South Australia, Australia

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Department of Physics, Drexel University, Philadelphia, PA, USA

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Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA

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Oskar Klein Centre and Department of Physics, Stockholm University, Stockholm, Sweden

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Department of Physics and Astronomy, Michigan State University, East Lansing, MI, USA

T. DeYoung,D. Grant,R. Halliday,A. A. Harnisch,A. Kochocki,E. Krupczak,K. B. M. Mahn,F. Mayhew,J. Micallef,H. Niederhausen,M. U. Nisa,S. C. Nowicki,B. Pries,D. Salazar-Gallegos,S. E. Sanchez Herrera,K. Tollefson,J. P. Twagirayezu,C. Weaver,N. Whitehorn&S. Yu

Department of Physics, University of Wuppertal, Wuppertal, Germany

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Karlsruhe Institute of Technology, Institute of Experimental Particle Physics, Karlsruhe, Germany

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Department of Physics and The International Center for Hadron Astrophysics, Chiba University, Chiba, Japan

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Department of Physics, Southern University, Baton Rouge, LA, USA

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Lawrence Berkeley National Laboratory, Berkeley, CA, USA

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Department of Physics, Chung-Ang University, Seoul, Korea

C. Ha

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Search for decoherence from quantum gravity with atmospheric neutrinos - Nature.com

Scientists recently created a never-before-seen four-atom molecule the coldest of its kind ever made.

Researchers created the oddball molecule a strange configuration of sodium-potassium with an ultralong chemical bond at 134 nanokelvin, or just 134 billionths of a degree above absolute zero. They described the ultracold material Jan. 31 in the journal Nature.

Ultracold systems are crucial to understand quantum behavior because quantum mechanics, the rules governing subatomic particles, dominate at low temperatures. These setups also let scientists precisely control the energy of particles to create quantum simulations, which model other quantum systems with physics we don't fully understand. For instance, studying the quantum behavior in a system of ultracold molecules could one day help scientists identify the material properties needed in high-temperature superconductors.

Related: Inside the 20-year quest to unravel the bizarre realm of 'quantum superchemistry'

The problem is that there's an inherent tradeoff: an ultracold system that is too simple may not capture the full array of behavior in interesting quantum systems. But add more complexity, and designing an effective experiment gets trickier.

"Usually people use atoms or ions and what makes them somewhat controllable is the fact that you have a relatively limited number of quantum states," Roman Bause, a quantum optics researcher at the University of Groningen in the Netherlands, told Live Science.

"But if I draw all the quantum states of a molecule, it will fill quite a thick book. It's a factor of a million or so more states."

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All these additional quantum states open up more interesting quantum questions, but also make the molecules difficult to cool.

To solve that problem, in the new study, Tao Shi, a physicist at the Chinese Academy of Sciences, and international collaborators used a multi-step cooling process, beginning with laser cooling to create the record-breaking molecules.

Related: How do lasers work?

This cooling method uses laser beams fired from all directions at a moving atom. The atom absorbs light and enters an excited quantum state, then immediately releases energy to return to its ground state. But, because of how the atom is moving relative to the laser beams (known as the Doppler effect), the atom releases a little more energy than it absorbs, cooling itself.

"The problem with using this technique for molecules is that there's not just one ground state. You would potentially need thousands of laser beams and it's just too much technical effort," Bause said.

However, ultracold atoms are an excellent starting point to build ultracold molecules. Using a mixture of ultracold sodium (Na) and potassium (K) atoms, Shi's team weakly associated these single particles into diatomic NaK molecules.

This is where the technical difficulties really started. "The problem with associating cold atoms is you heat them while doing this so then you need another cooling technique, evaporative cooling," Bause said.

For reasons no one quite understands, under these cooling conditions the molecules stick together and the experimenter can no longer precisely control them. This particular challenge has stumped researchers across the field for years.

But, by shining in precisely controlled microwaves, Shi's team overcame the clumping issue in the diatomic NaK molecules as they were cooled down to 134 nanokelvin.

The microwaves also had a unique advantage when getting the two NaK molecules to weakly associate and form one four-atom-molecule of (NaK)2. "If you shape the microwaves exactly right, what you have is a potential that's not just repulsive at short ranges but it's also attractive at longer ranges," Bause said.

As such, this first-of-its-kind four-atom molecule has a central bond 1000 times longer than the bond between the sodium and potassium atoms and was created at a temperature more than 3000 times colder than any previous four-atom molecule.

The new finds are exciting because they "will ultimately bring us to interesting places where we currently have no theoretical handle high temperature superconductors and materials for better lithium batteries for example," Bause said.

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Scientists made the coldest large molecule on record and it has a super strange chemical bond - Livescience.com