Physicists Have Discovered a New Paradox

According to him, in the future the researchers plan to analyze how this can be used in such promising materials as, for example, graphene.

These discoveries also provide an opportunity to resolve the paradox of Fermi-Pasta-Ulam-Tsingou. In 1953, a scientific group led by Enrico Fermi carried out a computer experiment that later became famous. Scientists considered the simplest model of oscillations of a chain of particles connected by springs. They assumed that the mechanical movement would gradually fade away, turning into chaotic thermal oscillations. Still, the result was unexpected: the oscillations in the chain first almost decayed, but then revived and reached nearly the initial level. The system came to its initial state, and the cycle repeated itself. The causes of mechanical oscillations from thermal vibrations in the considered system have been the subject of scientific research and disputes for decades.

The amplitude of mechanical vibrations caused by ballistic resonance doesn’t increase infinitely, but reaches its maximum; after that it starts gradually decreasing to zero. Eventually, mechanical oscillations fade completely, and the temperature equilibrates in the whole crystal. This process is called thermalization. For physicists, this experiment is vital because a chain of particles connected by springs is a good model of crystal material.

Researchers of the Higher School of Theoretical Mechanics showed that the transition of mechanical energy into heat is irreversible if we consider the process at the finite temperature.

According to experts, the theoretical approach proposed by the SPbPU scientists demonstrates a new approach to how we understand heat and temperature. It may be fundamental in the development of nanoelectronic devices in the future.