Chesi, Stefano

Stefano Chesi is currently an Associate Professor at the Beijing Computational Science Research Center (CSRC) in China. He received his Ph.D. in Condensed Matter Theory from Purdue University (2007) and held postdoctoral positions at the University of Basel (Switzerland) and McGill University (Canada). In 2013 he became a Research Scientist at RIKEN (Japan) and in 2014 joined CSRC, after being selected for the national "Young Thousand Talents" program. His research focuses on the theoretical description of quantum systems, with strong interests in spin coherence, solid-state quantum devices, and dissipative phase transitions.

For more details, visit his webpage at https://csrc.ac.cn/~stefano/.

Dynamics of spiral magnetic order in an electrically-biased Kondo chain

• Speaker: Stefano Chesi (Computational Science Research Center, China)
• Event: Quantum Technology Workshop 2026

We analyze a one-dimensional system of localized magnetic moments coupled to itinerant electrons, which has been proposed, in conjunction with proximity-induced superconductivity, to host a self-organized topological phase. Here, we characterize the magnetic properties of this model in the absence of superconductivity, by employing a non-equilibrium description of the itinerant electrons, combined with an adiabatic approximation and a phenomenological damping term for the localized spin dynamics. In the equilibrium limit, our approach reveals a weak spatial modulation of the predicted spiral order (i.e., the specific magnetic texture behind topological superconductivity). This modulation stems from an electronic instability that drives the system towards a fully gapped state. The presence of a finite gap, rather than half-metallic chiral states, could potentially hinder the formation of the topological phase. Furthermore, upon applying a finite bias, we uncover a complex landscape of dynamical regimes. At low bias, we find a rigidly-rotating non-coplanar magnetic structure, which transitions to quasi-periodic dynamics and ultimately to chaos as the voltage increases. These phases yield distinct signatures in both charge and spin transport. For the rigidly-rotating state, we analyze the dependence of the rotation axis and frequency on system parameters, demonstrate the transport of spin polarization between the two contacts, and show that the spin dynamics slows down in the thermodynamic limit, where a static conical state persists to arbitrarily long times.