28/06/2022

Nachbin contributes to solving a problem that intrigued Einstein.

One of the problems in quantum physics that intrigued Albert Einstein is receiving contributions with the participation of a Brazilian. Published on June 8th in the journal Nature Communication Physics, the article “ Hydrodynamic superradiance in wave-mediated cooperative tunneling ” includes among its authors the IMPA researcher André Nachbin. The article's theme is motivated by the question that Einstein called “spooky action at a distance.” In 1935, Einstein published an article with collaborators that became known as the EPR paradox. The Nature article deals with the interaction at a distance (correlations) between two particles, in this case droplets.

“Our work shows how two droplets, interacting at a distance, can cooperate to overcome barriers in the form of tunneling. We show that this is possible through the underlying wave, which promotes the interaction between the two particles,” explained Nachbin, who developed the study in collaboration with researchers from the Massachusetts Institute of Technology (MIT) and the Paris School of Industrial Physics and Chemistry (ESPCI Paris).

The IMPA researcher developed the mathematical model used in the computational experimentation of the problem, which has analogies with quantum physics. The theoretical model developed by Nachbin (Chaos magazine 2018, https://doi.org/10.1063/1.5050805) was an offshoot of the doctoral thesis by IMPA's Carlos Galeano-Rios (2015), in partnership with John Bush (MIT) and Paul Milewski (University of Bath, England).

In 2005, Yves Couder and Emmanuel Fort discovered that a drop of silica oil can levitate indefinitely on the surface of the same fluid if the container is vibrating at the correct frequency . Upon bouncing, the droplet generates waves around it, creating a self-propelled wave-particle composite system—that is, a new dynamic system. Researchers worldwide began investigating the dynamic properties of this new object and its various quantum analogies.

Nachbin explains that the work represents an important step in solving this question, which Einstein never resolved because at the time there was no information that is available today. "We were only able to make progress on this issue because of the experimental advances of Couder, considered the 'father' of this problem. In his Paris laboratory, he identified an unprecedented partnership between wave and droplet, which until then was thought to belong only to the quantum world."

In addition to the IMPA researcher, the article is signed by Konstantinos Papatryfonos (MIT and ESPCI Paris), John Bush (MIT), Matthieu Labousse (ESPCI Paris), Mélanie Ruelle (ESPCI Paris), and Corentin Bourdiol (ESPCI Paris).

This breakthrough opens up very fertile ground for applied mathematics, for the formulation of new equations, and for fundamental questions in physics, since a photon of light has both wave and particle properties. According to Nachbin, an ambitious plan is underway following this publication in Nature: the violation of Bell's inequality. Preliminary results with the theoretical model, formulated at IMPA, have been promising.