What happens when absolute zero temperature is reached?

Japanese researchers have managed to obtain the lowest temperature ever achieved. 


Its discovery will allow the development of materials with unimaginable properties

A group of researchers from Kyoto University in Japan and Rice University in the United States has managed to obtain the lowest temperature ever achieved in the laboratory , 3 billion times colder than deep space, which is still heated by the afterglow of the big bang , which is at 4.2 kelvins. To achieve this, they have cooled a Fermi gas of Ytterbium nuclei, which behaves like SU(6) matter, where SU stands for special unit group , a mathematical way of describing symmetry, and N=6 denotes the possible states of spin of the particles in the model, using laser cooling .

This milestone opens the door to developing new materials with unimaginable properties and to observing physical systems that cannot be explained by the laws of thermodynamics. We must resort to quantum mechanics to get closer to understanding them. This is the lowest temperature ever reached in the entire universe unless an extraterrestrial civilization is carrying out these same experiments somewhere in the cosmos and they have some advantage, but what happens to matter at such low temperatures? ? What we know is that the activity of the atoms will stop absolutely and strange things will happen.

As an example, at temperatures close to absolute zero, helium becomes superfluid, a state characterized by the complete absence of viscosity. This means that it can go through walls and any type of material, porous or not, and climb the walls of the containers that contain it. However, unlike most items, it does not freeze.

The first person to establish a temperature scale in an objective way was the Swedish astronomer and physicist Anders Celsius in 1742. Celsius created the scale that bears his name (Celsius temperature scale), which divides the range of temperatures between the melting points and boiling of water at atmospheric pressure in 100 divisions or degrees.

In Spain, until 1948, this scale was called the centigrade scale and, although many of us continue to use it, it is no longer strictly correct to do so. A century after the appearance of the Celsius scale, Lord Kelvin proposed the absolute temperature scale, whose zero is, effectively, absolute zero, corresponding to -273.15℃. This scale has a greater physical foundation since at zero kelvin matter stops shaking.

The temperature at which life is possible

The average temperature on land is about 14℃, with the lowest recorded temperature being -89.2℃ in Antarctica and the highest being 54.4℃ in Death Valley, California.

Actually, if we position the temperature ranges in which life as we know it is possible within the absolute temperature scale, we will realize that we are closer to absolute zero than to the highest temperatures in the universe. As an example, the surface of our star, the Sun, is approximately 5,600℃. Not so its center, whose temperature is estimated at 15 million degrees kelvin.

Everybody quiet! zero kelvin is close

At very high temperatures, all kinds of matter turn into gas and acquire very high speeds of agitation. On the contrary, at temperatures close to absolute zero, matter behaves in a very special way. Strictly, at zero kelvin, all motion stops, even the electrons orbiting the nuclei of atoms.

One of these very special behaviors, which occurs in a type of matter (formed by bosons such as atomic nuclei with integer spin or particles responsible for transmitting one of the four fundamental forces: photons, gluons, etc.), was predicted some time ago. over a century by Albert Einstein and mathematical physicist Satyendra Nathan Bose .

When a set of bosons reaches this state, they all fall to the lowest possible energy level. This state of matter is called a Bose-Einstein condensate , after the two physicists who predicted it.

If instead of bosonic matter, it is fermionic matter, such as half-integer spin nuclei, protons, electrons, etc., the state of matter that is reached near absolute zero is called a Fermi liquid , similar to a Fermi gas .

In some cases of extreme low temperature, a Fermi liquid can behave like a superfluid , that is, a fluid with strictly zero viscosity, which is capable of moving up a vertical wall like helium.

During the s. XIX science lived a frenetic race to achieve absolute zero . And the search continues. But now, with laser cooling techniques, we’re really close.The Conversation

Francisco José Torcal Milla , Full Professor. Department of Applied Physics. Center: EINA. Institute: I3A, University of Zaragoza

This article was originally published on The Conversation . Read the original .