According to classical physics, the universe tends to equilibrium but the same does not apply to quantum systems, which are destined to shift constantly between different configurations without ever finding peace. A theoretical study conducted by SISSA and the University of Oxford illustrates this dramatic difference and explains that in order to be described correctly one-dimensional quantum systems should be thought of as being defined on discrete points in space.
A quantum system never relaxes. An isolated system (like a cloud of cold atoms trapped in optical grids) will endlessly oscillate between its different configurations without ever finding peace. In practice, these types of systems are unable to dissipate energy in any form. This is the exact opposite of what happens in classical physics, where the tendency to reach a state of equilibrium is such a fundamental drive that is has been made a fundamental law of physics, i.e., the second law of thermodynamics, which introduces the concept of entropy.
This profound difference is the subject of a study published in Physical Review A, conducted with the collaboration of the International School of Advanced Studies (SISSA) of Trieste and the University of Oxford. Giuseppe Mussardo, professor at SISSA, together with Milosz Panfil, SISSA research fellow, and Fabian Essler from the University of Oxford carried out a theoretical analysis with which they demonstrated the peculiarity of one-dimensional quantum systems, as well as explaining the non-local nature of these systems.
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