An experiment conducted by scientists at the Vienna Center for Quantum Science and Technology has shown that in the quantum world, the transition to thermal equilibrium is more interesting and more complicated than previously thought .
As noted by the study, published in Science , between initial ordered state and a final state statistically mixed, can emerge a “quasi-stationary intermediate state.” This intermediate state already exhibits some properties such as balance , but some of the features of the initial state remain visible for a very long time. This phenomenon is called “pre-thermalization” and plays an important role in various nonequilibrium processes in quantum physics. could, for example, help us understand the state of the early universe .
Originally come from the same atom
“In these experiments began with a one-dimensional quantum gas of ultracold atoms, the so-called Bose-Einstein condensate, which was split in two by a fast atom chip,” explained Professor Jörg Schmiedmayer. When the two parts of the condensation bind create a wave interference pattern ordered material . “The shape of this interference pattern shows that the two parties have not forgotten that originally come from the same atom,” he noted.
After some time, it is expected that the atomic cloud cleaved store thermal equilibrium . The longer is added before the two halves back together, the observed order of interference patternsdisintegrates . “The amazing thing about this is that the order does not go directly to a minimum. First decomposes quickly, but then remains in an intermediate state, “he pointed one of the authors, Michael Gring.
According to the researchers, “at first it was not clear how to interpret this phenomenon. L os experiments had to be improved and developed the corresponding theory better. “
In close collaboration with the group of Professor Eugene Demler of Harvard University , these surprising results could be explained. The transition from thermal equilibrium systems is important in many fields of quantum physics. After all, a quantum experiment can not be performed at a temperature of absolute zero. Therefore, scientists always have to deal with the effects of temperature.
Performing calculations and data storage in a quantum computer create nonequilibrium states , which (like an ice cube in hot water) tends to thermal equilibrium, the destruction of the quantum state. The new intermediate state may also be of interest to the physics of quark-gluon plasma. During the first fractions of a second after the Big Bang, all matter in the universe was in a state of non-equilibrium quark-gluon plasma .
Today, the creation of quark gluon plasma is carried out by large collider. These experiments have shown that certain aspects of the plasma tend to thermal equilibrium much faster than might be expected. processes associated with the decay of a quantum system to thermal equilibrium could also provide information on the relationship between quantum physics and classical macroscopic world.
“The clouds of atoms offer the possibility to study in detail the fascinating intersection of nonequilibrium states at thermal equilibrium,” explained Schmiedmayer, who added that “in this way, it is expected to achieve a deeper understanding of the nonequilibrium processes, which are ubiquitous in nature. “