General, Research, Technology

Physicists have fixed thousands of molecules in one quantum state

The author of a new study published inThe journal Nature seems to have succeeded in solving one of the most important problems of quantum physics - they demonstrated how to bring several molecules at once into a single quantum state. Let me remind you that when a group of particles, cooled to absolute zero, share a single quantum state and the whole group begins to behave as if it were one atom, physicists talk about a Bose-Einstein condensate. This state is certainly difficult to achieve, but when it happens, a whole world of new possibilities opens up. Scientists have been doing this with atoms for decades, but if they had done the same with molecules, today we would probably have different forms of quantum technology. But since molecules are larger than atoms and have many more moving parts, most attempts to curb them have failed. However, this was the case until the end of April this year - in the course of a new study, a team of physicists cooled the cesium atoms, and then confined the molecules so that they were on a two-dimensional surface and could only move in two directions. The result is a set of practically identical molecules in a single quantum state.

Wow! Here is a bosonic analogue of the transition from a Bose-Einstein condensate to a Bardeen-Cooper-Schrieffer superfluid liquid in a Fermi gas.

What is Bose-Einstein condensate

As is known, both convolution andsuperconductivity is the result of changes in the behavior of clusters of quantum particles at low temperatures. The phenomenon associated with this involves the creation of a completely new state of matter. In addition to the three known states of matter - liquids, gases and solids, there is a fourth - plasma. It occurs when a gas is heated to temperatures at which atoms lose electrons and turn into charged ions. Ions are often formed in chemical reactions, such as those where salt (sodium chloride) dissolves in water, producing sodium and chlorine ions, or those that heat a gas.

It is also interesting that plasma is the most common substance in the universe since it is mainly composed of stars,which make up the bulk of galaxies (not counting dark matter). We also encounter plasma in everyday life - when we look at flames or at types of flat screen TVs. But at the cold end of the temperature scale there is fifth state of matter - Bose-Einstein condensate.

Standard Model of Particle Physicsdivides particles into two groups that do not obey the exclusion principle: fermions (electrons and quarks) and bosons (photons). Bosons usually do not interact with each other, and many of them can coexist in the same quantum state.

Bose-Einstein condensation forms when a gas is cooled to near absolute zero.

Bose-Einstein condensate contains a huge number of particlesconnected to each other in such a way that this connection allows them to behave like one large boson, endowing matter with such unusual properties as the ability to capture light. The name "Bose-Einstein" refers to the model used to describe the collective behavior of particles - "Bose-Einstein" statistics - one of two options for how quantum particles can behave. Another option is the Fermi-Dirac statistics.

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How to fix molecules in one quantum state?

In a new study published inin Nature on April 28, a team of scientists from the University of Chicago cooled the cesium atoms to almost absolute zero - in this state, each atom is stationary, and all electrons are at a lower level; theoretically this occurs at -273.15 degrees Celsius (0 degrees Kelvin). This happened in several stages.

The first was to cool the entire system down to 10nanokelvin - a hair above absolute zero. Then they packed the molecules into a creeping space so that they were pressed flat. “Typically, molecules want to move in all directions, and if you allow them to, they become less stable. We limited the molecules so that they were on a two-dimensional surface and could only move in two directions, ”the study authors write.

See also: Why is quantum physics akin to magic?

Prof.Chen Chin in a laboratory at the University of Chicago. His lab has announced a breakthrough in bringing multiple molecules into one quantum state. This is one of the most important goals in quantum physics.

The result is a set of practicallyidentical molecules - lined up with exactly the same orientation, the same vibration frequency and in the same quantum state. Scientists have described this molecular condensate as a blank sheet of new drawing paper for quantum engineering.

“This is an absolutely perfect starting point.For example, if you want to build quantum systems for storing information, you need to start from scratch before you can format and store that information, ”lead study author Chen Chin of the University of Chicago told Sciencealert.

It is noteworthy that until now scientists have been able tolink together up to several thousand molecules in this state and they are just beginning to explore its potential. As the authors of the scientific work explain, in the traditional understanding of chemistry, we usually think that several atoms and molecules collide and form a new molecule. But in a quantum state, all molecules act together to exhibit collective behavior. This opens up a whole new way of studying how molecules can interact with each other to become a new type of molecule.

You will be wondering: Is the world really on the verge of discovering a "new physics"?

The results of the work, as its authors hope, inthe future may form the basis of forms of quantum technology. Among other things, because of their rich energy structure, cold molecules can help advancements in quantum engineering and quantum chemistry. In general, on the face of all the evidence that in the near future we are expecting many amazing discoveries.