Researchers Create Quantum Droplet that Exists for 25 Trillionths of a Second

The dropleton was created by researchers at the Philipps-University of Marburg, Germany, and Joint Institute for Lab Astrophysics at the University of Colorado.

The dropleton is actually a combination of positively charged holes and negatively charged electrons. Holes are described as places in the semiconductor where the electrons are missing. The dropleton is the first quasiparticle that behaves like a liquid.

What was already known is that electrons and holes can form pairs called excitons when bombarded by light. In the current study, researchers created a cluster of these electrons and holes that had properties of both liquid and a quantum particle.

According to a statement by the National Institute of Standards and Technology, the dropleton can have ripples just like water.

Previously, researchers have described the existence of quasiparticles such as holons, spinons and orbitons. According to its creators, the dropleton is the first quasiparticle that has liquid properties.

Researchers created the new quasiparticle by shooting an "ultrafast red laser" at a gallium-arsenide semiconductor. The pulses initially form excitons. At a certain density of these excitons, the holes and electrons form clusters that act like a liquid.

The positively charged holes and negatively charged electrons make a neutral droplet. According to the researchers, the droplets are like bubbles within the matter. In a quantum droplet, all electrons and holes interact equally with each other.

"Electron-hole droplets are known in semiconductors, but they usually contain thousands to millions of electrons and holes," said JILA physicist Steven Cundiff, professor of physics at CU-Boulder and one of the study authors. "Here we are talking about droplets with around five electrons and five holes.

The particle currently has a lifetime of about 25 trillionths of a second (25 picoseconds). The dropletons could help researchers understand quantum mechanics.  

"Regarding practical benefits, nobody is going to build a quantum droplet widget. But this does have indirect benefits in terms of improving our understanding of how electrons interact in various situations, including in optoelectronic devices," Cundiff said in a news release.

The study is published in the journal Nature.

The research is supported by the National Science Foundation, NIST and the Alexander von Humboldt Foundation.