Physical Chemistry Seminar: Professor Vojtech Vlcek, UC Santa Barbara
About the Seminar
Excitations Dynamics Driving Electronic Correlations in Molecules and Solids
Capturing the dynamics of electronic excitations in realistic systems containing more than a few electrons is one of the outstanding theoretical challenges. Dynamical quantum fluctuations mediate interactions among excited electrons (and holes), determining the material electronic structure and optoelectronic response. A predictive ab initio theory is critical for understanding, predicting, and designing novel compounds with tailored (quantum) properties. In this talk, I will discuss my group's developments tackling the first-principles description of excitation dynamics in molecular and condensed systems containing up to several thousands of electrons. We employ the concept of downfolding - "compression" of the (otherwise intractable) many-body problem on an effective few-body problem solved by a combination of real-time evolution of quantum fluctuations. Conceptually, the methodology is improvable by accounting for systematically higher and higher-order correlators. Our work overcomes the limitations of traditional methods and exhibits low scaling of the computational cost and high accuracy. I will exemplify the methodologies on practical applications to large-scale quantum condensed matter systems, e.g., twisted bilayer graphene, quantum defects, and selected molecular problems. These efficient low-scaling numerical techniques arguably constitute an ideal platform for simulating excitations in complex nanoscale systems.
About the Speaker
Dr. Vlcek received his Ph.D. in 2016 jointly from The Hebrew University of Jerusalem (Israel) and the University of Bayreuth (Germany), where he studied in the chemistry and physics departments. His PhD was sponsored by the Minerva Fellowship of the Max Planck Society. From 2016 to 2018, Dr. Vlcek continued as a postdoctoral researcher at UCLA in the Department of Chemistry and Biochemistry. He joined the chemistry faculty at UCSB in 2018, and since 2023 he is also affiliated with the Materials Department at UCSB. He received an NSF Career award in 2020, he has been named an emerging leader by the Editorial Boards of the Journal of Physics: Condensed Matter and an Emerging Investigator by the Journal of Chemical Physics. His research focuses on quantum many-body techniques and the description of electronic excitation dynamics in materials. He is leading a multidisciplinary DOE partnership to tackle the non-equilibrium in driven quantum systems.
Host: Todd Martinez