The world's first successful generation of "time crystals"

ByClint Budd

"crystal"Refers to a substance in which atoms and molecules are arrayed with spatially repeating patterns, but this repeating pattern has also been extended in the time directionTime crystalsThe creation of "the world's first successful creation.

Physicists Create World's First Time Crystal

The concept of "time crystals" was born in 2012, a physicist at the Massachusetts Institute of TechnologyFrank WillcheckHe advocated. Time crystal refers to a four-dimensional crystal structure that the regular array of particles extends not only in three-dimensional space but also in the time direction. Mr. Wilcheck did not mention the specific method of generating time crystals at the time of advocating, but later Lawrence Berkeley National Laboratory in the United States had raised how to generate it.

"Four-dimensional space-time crystal, can actually be made" Berkeley Laboratory creates manufacturing method | SJN News Renewable energy latest information

Crystallization in three-dimensional space means continuous spatial symmetry breaking that occurs when heat is removed from a molecular system of a certain substance to a low energy state. It can be explained that crystallization is a phenomenon in which a structure symmetrical with respect to all directions in a substance is broken by being placed at a low temperature and a phenomenon in which discrete symmetry (becoming symmetric only in a specific direction) appears. Spatiotemporal crystals are structures in which this discrete symmetry is extended also in the time direction, and regular patterns appearing in crystals appear with periodicity not only in space but also in time.

For example, it can be seen that particles that continue a circular movement permanently in zero friction state are crystallized in the time direction. In space-time crystals brought up by the team of the Berkeley laboratory, by utilizing the electric field ion trap and the interparticle Coulomb repulsion under cryogenic temperature, the trapped ions permanently rotate and the structure is temporally As shown in FIG. Since such a space-time crystal has the lowest quantum energy state, temporal order is kept permanently, theoretically the rest of the universe reaches thermal equilibrium state (thermal death) due to entropy increase It seems that crystals will persist even after doing it.

However, after that, a paper that mathematically proved that temporal crystals are not feasible is published by Yuki Watanabe, a graduate student at the University of California, Berkeley, and Professor Masashi Oshikawa of the University of Tokyo. Time crystals were considered to be nonexistent.

(PDF)Proof that 'time crystal' is impossible - clearly deny the novel award of Nobel Prize physicist ~

Mathematically proved that "time crystals" can not be realized | Science - Nikkei Newspaper

In this research, we evaluate the temporal correlation function of macroscopic physical quantity in the state of stable substances (equilibrium state) guided by statistical mechanics, and that it does not oscillate in time by using strict inequality Mathematics I proved it. This means that as long as it complies with statistical mechanics, "time crystal" actually does not exist.

Meanwhile, the research team led by Professor Chris Monroe of the University of Maryland on October 4, 2016 succeeded in creating time crystals for the first time in the world. The basic process for creating time crystals is very simple, creating a quantum system like an ion group in a ring shape and cooling it until the state of energy is lowest. Then, in terms of the physical law, the ring will be completely stationary.

In addition, the research team mentioned the use of temporal crystals, "quantum information task to realize powerful quantum memory" and so on. However, there are also many other characteristics that are not fully understood yet, and if you do not carefully consider the properties, it will not be that you have shown that time crystals really exist.

in Science, Posted by logu_ii