Thanh Nguyen, a Condensed Matter ICTP Associate from Vietnam, has published a paper in the prestigious science journal Physical Review Letters, in collaboration with ICTP scientist Mikhail Kiselev.
The paper, “Thermoelectric Transport in a Three-Channel Charge Kondo Circuit”, is the result of a long collaboration between the two scientists. Nguyen wrote the paper during her most recent stay at ICTP, a visit that was prolonged by the outbreak of the Covid-19 crisis in Italy.
Nguyen has been visiting ICTP since her appointment as a postdoctoral fellow here in 2007, after obtaining a PhD in France. During her time in Trieste, she worked with Kiselev on the topic of Kondo physics, studying the scattering of conduction electrons in a metal due to magnetic impurities. In 2010, she began a second postdoctoral position at the University of Cincinnati. She then decided to go back to Vietnam, but has continued to visit ICTP often as a Regular Associate since 2016. Thanks to the support of ICTP, she has also participated in several schools and workshops around the world, including some in Vietnam, India, Thailand and South Korea.
“I have spent quite a long time at ICTP with many fruitful visits,” says Nguyen. “ICTP is a great institute with many great professors, with many scientific activities each year, with a big library and the ability to access many journals.” The atmosphere of collaboration and cooperation at ICTP, and its vibrant and multicultural environment, impressed her from the very beginning of her involvement with the Centre. “I have great memories of my postdoc time at ICTP,” she says. “Some postdocs that were staying there at the same time became my close friends and we still keep in contact.”
The paper, published on PRL on 8 July, focusses on a topic Nguyen and Kiselev have been working on for more than ten years. In this work, they investigate theoretically the phenomenon of thermoelectric transport, implementing the so-called Kondo model through a quantum simulator. The Kondo effect is one of the most important effects in strongly correlated electron systems, a set of compounds that show unusual electronic and magnetic properties and can often have very useful technological applications.
Recently, some breakthrough experiments, especially those performed at the Centre for Nanoscience and Nanotechnology in France, convincingly demonstrated the paramount importance of the multi-channel Kondo physics for the quantum charge transport through nano-devices. With the rapid development of nanotechnologies, it is particularly challenging to investigate the Kondo effect in quantum devices, for the application in quantum technology and the implementation of hardware for quantum computers.
Nguyen's arrival at ICTP at the beginning of February 2020 to work on this project coincided with the Coronavirus outbreak in Italy. She was not expecting the situation to escalate so quickly and have such global and serious effects, so she decided not to go back to Vietnam, as suggested by the Associates Office. “We were waiting for the reports from referees for our manuscript submitted at the very end of 2019,” she remembers. “A paper in Physical Review Letters, one of the most respectful high-impact journals in physics, is a dream of many physicists. If I returned to Vietnam, I might not have been able to access my emails and work during the quarantine, or I might have gotten Coronavirus during my trip. So, I decided to stay.”
However, her stay has not been easy. “When the whole of Italy was locked down, I was really terrified. I tried to work as much as I could, but honestly, I haven't been able to work as effectively as usual during that time,” she admits. “What made me satisfied was that we have responded well to the questions of the referees, and edited the manuscript according to their suggestions so that our paper was finally accepted for publication in Physical Review Letters.”
Nguyen has now been able to return safely to her home in Vietnam, and is continuing to work, connecting online with her colleagues and working remotely on more projects with Kiselev. “I think the Covid-19 pandemic is the most memorable time for our generation,” she says, “I hope this crisis will be over soon, that everything will soon be reset to how it used to be and that I will be able to visit ICTP again in the future.”
---- Marina Menga