Dr. Lisandro Hernandez de la Peña, assistant professor of Chemistry at Kettering University, was invited to speak at the Energy Materials Nanotechnology (EMN) Meeting on Quantum Technology in April. The conference, hosted by the Chinese Academy of Science Institute of Semiconductors, was held in Beijing, China.

“It was an honor to represent Kettering University at a conference that featured faculty from universities around the world,” Hernandez de la Peña said. “It gave me the opportunity to highlight some of the great things about Kettering to a worldwide audience.”

The EMN Meetings were formerly a workshop series that began in 2008. Since, they’ve grown and organized multiple workshops themed around energy, materials and nanotechnology. They’ve been held at locations around the world, including the United States, Greece, the U.S. Virgin Islands and Mexico. This conference in Beijing was developed as a platform for leading scientists, researchers, scholars and engineers from education, labs and industry to share and discuss the latest developments in quantum science and technology.

Hernandez de la Peña presented a talk entitled, “Quantum Free Energies from Non-Equilibrium Processes: A Path Integral Approach”, a work that pertains to the framework of the thermodynamics of small systems.

“Small systems are allowed to follow rules that differ from the ones known to macroscopic systems,” Hernandez de la Peña said. “Recent and prominent results collectively known as nonequilibrium fluctuation relations, for example, indicate how to compute the free energy change of a process in a small system from the irreversible work involved, something untenable from the standpoint of classical thermodynamics.”

Small systems can also exhibit quantum behavior and the analysis becomes, in this setting, particularly challenging because their time-evolution is in general an intractable problem.

“In our work, we use the fact that the thermodynamics of a quantum system is equivalent to the one of a certain classical system with infinite degrees of freedom and show that the ‘nonequilibrium fluctuation relations’ also hold in this context,” Hernandez de la Peña said. “This work provides the only viable route for an exact nonequilibrium calculation of free energy change in quantum systems.”

The strategy was applied to study the free energy change associated to the escape of an ion trapped by a cluster of water molecules where the protons are treated quantum mechanically. However, this approach can be used quite generally to analyze all sorts of microscopic processes, including the functioning and efficiency of biological molecular machines where quantum effects might not be necessarily negligible.

For more on Hernandez de la Peña’s work, visit his website.

An animation of nonequilibrium methods in quantum systems