What happens when absolute zero temperature is reached?

A group of researchers from Kyoto University, in Japan, and Rice University, in the United States, have managed to obtain the temperature in the laboratory. lowest ever3 billion times cooler than deep space, which is still warming with the radiance of the big bang, which is at 4.2 kelvin. To achieve this, they have cooled a Fermi gas of Ytterbium nuclei, which behaves like a SU(6) matter, where where SU stands for special unit groupa mathematical way of describing symmetry, and N=6 denotes the possible spin states of the particles in the model, using laser cooling.

Quantum mechanics

This milestone opens the doors to develop New Materials with unimaginable properties and to observe physical systems that cannot be explained with 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.

Tell me how you move and I’ll tell you what temperature you’re at

Temperature is a macroscopic measure of the degree of atomic and/or molecular agitation that matter has. The higher the agitation, the higher the temperature. In the case of a single-atom gas, such as helium, the agitation is reduced to Brownian movement. In biatomic gases, such as oxygen, internal vibrations or oscillations must be added to the state of agitation, and so on.

The first person to establish an objective temperature scale was the Swedish astronomer and physicist Anders Celsius in 1742. Celsius created the scale that bears his name (Celsius temperature scale), which divides the temperature range between the melting and boiling points of water at atmospheric pressure into 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. more than a century for Albert Einstein and the expert in mathematical physics 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 Bose–Einstein condensate, in tribute to the two physicists who predicted it. If instead of bosonic matter, we are dealing with fermionic matter, such as half-integer spin nuclei, protons, electrons, etc., the state of matter that is reached near absolute zero is called Fermi liquidsimilar 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 ascending a vertical wall as occurs with 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.

Font: Francisco José Torcal Milla / THE CONVERSATION

Reference article: https://theconversation.com/what-occurs-when-reaching-absolute-zero-temperature-191702