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Scientists were able to do something incredible: they were able to cool the substance is lower than the temperature, which until now was considered as an absolute minimum. In most modern textbooks on physics absolute zero on the Kelvin or minus 273,15 degrees Celsius is the lowest possible temperature, as it is the lightest element, hydrogen - completely loses its mobility, that is, figuratively speaking, freezes.
Strangely enough, but one of the ways to study negative temperatures is infinitely strong heating of the substance. This unusual bordering on fantasy, approach allows theory to design engines, the efficiency of which is above 100%, sheds light on these mysterious substance, as dark energy and others.
From the point of view of nuclear physics, the temperature is the speed. The speed of movement of atoms inside the compound, and the faster atoms move, the higher the temperature. Accordingly, at minus 273,15 degrees hydrogen atoms completely stopped. With this approach, no matter cannot be colder than this limit.
However, modern physics, to understand the essence of temperature, offers a look at it differently, not as a linear measure, but as a loop: positive temperature is one part of the cycle, a negative one another. At temperatures seeking infinitely low or infinitely high, scale sooner or later turns out to be negative. At positive temperatures the atoms often take lower energy state, negative - high. In physics this effect is known as the Boltzmann distribution.
At absolute zero atoms occupy the lowest energy state, and at infinite temperature, the atoms can take immediately all energy States. Accordingly, at very high temperatures, they take all the high energy state, and at very low temperatures - all low.
"Speaking of low temperature, we can say that we are dealing with an inverted Boltzmann distribution," says physicist Ulrich Schneider of the University of Munich in Germany. "With this logic, a substance reaches a temperature below absolute zero, it becomes hot. We believe that when reaching the milestone of minus 273 degrees temperature is not over but just goes to negative values".
It is easy to assume, objects with a negative temperature behave very strange. For example, usually energy coming from an object with a higher temperature, will always be greater than the cooler object. However, if the matter goes to the negative scale, there than it is colder, the more energy it emits. Thus, here cooler object will always be more energetically active, rather than warmer.
Another strange consequence of negative temperatures is entropy is a measure of how much substance is ordered. When the object is of a traditional temperature, it increases the entropy of matter around and inside myself, but when the temperature goes into the negative zone, endlessly cold/hot object can reduce the entropy within and around them.
German physicists say that negative temperature is still largely theory. But it will become a practice, when science will learn to work with a clear energy performance of a single atom of matter. When researchers will be able to work with one single atom, just as with objects in the macrocosm, we can talk about whether atoms cooled to super-low temperatures or whether they can fly faster than the speed of light.
Meanwhile, for the generation of negative temperatures scientists have created a system in which the atoms have had a hard limit of what energy they possess. To do this, physics took 100,000 atoms and cooled to a temperature one-billionth of a degree Kelvin. The atoms were cooled in a vacuum chamber, isolated from the external environment. For precise control of atoms, researchers used a network of laser rays and magnetic fields.
According to scientists, the temperature of the substance ultimately depends on how much potential energy of the atom and how much energy is formed from the interaction between atoms. Also, the temperature is also closely connected with pressure - the hotter the object, the more it expands, and Vice versa. To make sure that the gas may have a temperature below absolute zero, it was necessary to create such conditions in which the atoms would not have a significant energy, and the repulsion of the atoms would be formed more energy than their attraction.
Something similar happened to recreate on the nanoscale. Simon brown of the University of Munich says that in the future, in practice such knowledge can lead to the creation of a super-efficient thermal engines. The work of such engines based on the conversion of thermal energy into mechanical energy. Theoretically, with negative temperatures such engines would have efficiency above 100%, although from the point of view of logic it seems impossible.