Quantum physics: Physicists develop a new theory for Bose-Einstein condensates

June 17, 2020

Bose-Einstein condensates are often described as the fifth state of matter: At extremely low temperatures, gas atoms behave like a single particle. The exact properties of these systems are notoriously difficult to study. In the journal Physical Review Letters, physicists from Martin Luther University Halle-Wittenberg (MLU) and Ludwig Maximilian University Munich have proposed a new theory to describe these quantum systems more effectively and comprehensively.

Research into the exotic state of matter dates back to Albert Einstein, who predicted the theoretical existence of Bose-Einstein condensates in 1924. "Many attempts were made to prove their existence experimentally," says Dr Carlos Benavides-Riveros from the Institute of Physics at MLU. Finally, in 1995, researchers in the U.S. succeeded in producing the condensates in experiments. In 2001 they received the Nobel Prize for Physics for their work. Since then, physicists around the world have been working on ways to better define and describe these systems that would enable their behaviour to be more accurately predicted.

This normally requires extremely complex equations and models. "In quantum mechanics, the Schrödinger equation is used to describe systems with many interacting particles. But because the number of degrees of freedom increases exponentially, this equation is not easy to solve. This is the so-called many-body problem and finding a solution to this problem is one of the major challenges of theoretical and computational physics today," explains Benavides-Riveros. The working group at MLU is now proposing a method that is comparatively simple. "One of our key insights is that the particles in the condensate interact only in pairs," says co-author Jakob Wolff from MLU. This enables these systems to be described using much simpler and more established methods, like those used in electronic quantum systems.

"Our theory is in principle exact and can be applied to different physical regimes and scenarios, for example strongly interacting ultracold atoms. And it looks like it will be also a promising way to describe superconducting materials," concludes Jakob Wolff.
-end-
About the study: Benavides-Riveros C. L., Wolff J., Marques M. A.?L. & Schilling C.. Reduced Density Matrix Functional Theory for Bosons. Physical Review Letters (2020). doi: 10.1103/PhysRevLett.124.180603 https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.124.180603

Martin-Luther-Universität Halle-Wittenberg

Related Physics Articles from Brightsurf:

Helium, a little atom for big physics
Helium is the simplest multi-body atom. Its energy levels can be calculated with extremely high precision only relying on a few fundamental physical constants and the quantum electrodynamics (QED) theory.

Hyperbolic metamaterials exhibit 2T physics
According to Igor Smolyaninov of the University of Maryland, ''One of the more unusual applications of metamaterials was a theoretical proposal to construct a physical system that would exhibit two-time physics behavior on small scales.''

Challenges and opportunities for women in physics
Women in the United States hold fewer than 25% of bachelor's degrees, 20% of doctoral degrees and 19% of faculty positions in physics.

Indeterminist physics for an open world
Classical physics is characterized by the equations describing the world.

Leptons help in tracking new physics
Electrons with 'colleagues' -- other leptons - are one of many products of collisions observed in the LHCb experiment at the Large Hadron Collider.

Has physics ever been deterministic?
Researchers from the Austrian Academy of Sciences, the University of Vienna and the University of Geneva, have proposed a new interpretation of classical physics without real numbers.

Twisted physics
A new study in the journal Nature shows that superconductivity in bilayer graphene can be turned on or off with a small voltage change, increasing its usefulness for electronic devices.

Physics vs. asthma
A research team from the MIPT Center for Molecular Mechanisms of Aging and Age-Related Diseases has collaborated with colleagues from the U.S., Canada, France, and Germany to determine the spatial structure of the CysLT1 receptor.

2D topological physics from shaking a 1D wire
Published in Physical Review X, this new study propose a realistic scheme to observe a 'cold-atomic quantum Hall effect.'

Helping physics teachers who don't know physics
A shortage of high school physics teachers has led to teachers with little-to-no training taking over physics classrooms, reports show.

Read More: Physics News and Physics Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.