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New shortcuts in quantum simulation could open new doors for technology

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From boiling water into steam to melting ice in glass, we have seen phenomena in our everyday lives known as phase transitions. But there is another type of phase transition that is harder to see. quantum Phase transition.

When cooled to near absolute zero, certain materials can undergo these quantum phase transitions, which can drop the jaws of physicists. Materials can flip from magnetic to non-magnetic, or they can suddenly acquire the supernatural ability to conduct electricity with zero energy lost as heat.

The mathematics behind these transitions are difficult even for supercomputers to handle, but new research from the University of Chicago suggests new ways to handle these complex calculations that will eventually lead to technological It can lead to breakthroughs. The shortcut takes only the most important information into the equations and creates a ‘map’ of all possible phase transitions in the system under simulation.

“This is a potentially powerful way to probe quantum phase transitions that can be used on both conventional and quantum computers,” said theoretical chemist and senior author at the University of Chicago’s Department of Chemistry and the James Frank Institute. One David Mazziotti said. of research.

He and other scientists believe that a full understanding of the complex physics behind quantum phase transitions could open the door to new technologies. For example, similar discoveries in the past have led to his MRI machines and transistors that make modern computers and phones possible.

streamlined approach

Well-known phase changes such as evaporation and condensation are caused by temperature changes. However, quantum phase transitions are induced by environmental interferences such as magnetic fields.

This phenomenon occurs as a result of many electrons interacting with each other. This is a kind of interaction that falls into the notoriously complex subfield known as “strongly correlated” physics. Traditionally, to simulate these quantum phase transitions, scientists have had to create models that incorporate all single-electron possibilities. But the computational power required to run these simulations quickly spirals out of control.

Quantum computers are thought to be better suited for this kind of problem than classical computers, but there are obstacles to this approach as well. For example, these problems create large amounts of data that need to be translated back into the “normal” computer language, and so on. for scientists to work with them.

So researchers wanted to know how to simplify the calculations without compromising accuracy.

Instead of creating a simulation that computes all the variables of a given quantum system, they found another approach: imputing a series of numbers that describe possible interactions between each pair of electrons. This is called the “two-electron density matrix”.

“By measuring the set that describes the two-electron density matrix, we create a map of all the different phases that a quantum system can experience,” says graduate student Sam Warren, the first author of the study. explained.

This “map” itself also has useful advantages, he said. ”