Destined never to relax: A theoretical study on quantum systems
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.
"The main point of our work was not only realizing the dramatic difference between classical and quantum reality," explains Mussardo, "but also discovering the existence of quantum systems that are extremely robust with respect to any external stimulus, thanks to their specific laws of symmetry.
These laws, in particular, demand not only the conservation of energy but also of innumerable other quantities, which maintain the same value over time as a result".
Mussardo and colleagues also made another discovery: to be able to predict the evolution of quantum systems and their statistical characteristics, we should think of them as being defined not by every point in space (and therefore continuous) but only by discrete points.
It is as if these systems lived "intrinsically" on a grid, explains Mussardo (who also adds that "this came as a big surprise"), "so that on a large scale we have to take into account non-local effects".
This study, as well as shedding light on some peculiar effects revealed by recent experiments on mixtures of cold atoms and spin chains, opens up interesting scenarios on the control of extensive quantum systems and their use for future memory architectures and quantum algorithms.
Federica Sgorbissa | EurekAlert!
Study offers new theoretical approach to describing non-equilibrium phase transitions
27.04.2017 | DOE/Argonne National Laboratory
SwRI-led team discovers lull in Mars' giant impact history
26.04.2017 | Southwest Research Institute
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences