Student Colloquium 11/6

Please join us for the next PGSA colloquium. It will be today at 4:00pm in room 144 Loomis. We are pleased to be hearing from Rachael Mansbach. The title and abstract of the talk are below.

Peptide folding and aggregation: Multiscale modeling and machine learning

The sequence of proteins determines their structure and function.  Understanding this interplay is fundamental to the understanding and rational design of new biomolecules.  I present a proposal for a project that applies atomistic molecular dynamics, coarse-grained molecular dynamics, and dissipative particle dynamics, as well as statistical mechanical theory, kinetic aggregation models, and machine learning to systems of engineered peptides: (i) for ultrahelicity and antimicrobial activity and (ii) for self-assembly into optically and electronically active biocompatible nanowires. The primary goal of this project is to understand and rationally design peptides to fold and assemble structural and functional nanostructures.

Student Colloquium 10/16

We are happy to announce that we have another Student colloquium this week. Please join us at 4:00pm today in Loomis 144 to hear about Sean Vig's work.

Title:
Characterization of the low-energy bosonic modes in Bi₂Sr₂CaCu₂O_8+x with incipient charge order

Abstract:
Cuprate high-temperature superconductors have been studied intensely for the past 30 years, understanding the mechanism responsible for superconductivity remains a significant challenge in condensed matter physics. Developing this understanding requires knowledge of both the fermionic charge excitations and many-body bosonic interactions that drive the associated emergent phenomena. Through work done through the Center for Emergent Superconductivity (CES), we have developed the technique of momentum-resolved electron energy-loss spectroscopy (M-EELS). M-EELS is capable of performing a full momentum-space mapping of the low-energy bosonic degrees of freedom over the first Brillouin zone with meV energy resolution, allowing us to characterize the interactions that give rise to collective electron dynamics. We present a study of the high-temperature superconductor material Bi₂Sr₂CaCu₂O_8+x (Bi2212) using M-EELS to measure low-energy electron dynamics. In optimally doped Bi2212, we find the emergence of static, short-range charge order at low temperature. The full measurement of χ"(q,ω) shows low-energy charge excitations, and resolving these excitations in momentum space, we see these excitations carry a similar structure to the charge order, suggesting that the static electronic order modulates the many-body interaction. We show that this observation is qualitatively consistent with features observed in the single particle spectral function by ARPES, namely the nodal dispersion anomaly, or “kink”.

PGSA Student Colloquium

The PGSA is resuming its student colloquium. For the new grad students, this is a weekly talk presented by you and your grad student colleagues organized by the PGSA on Fridays at 4:00 in Loomis 144 and will include refreshments. To make this happen, we need people to sign up to give presentations. This is a great chance to practice for your prelim, polish up for your thesis defense, or get ready for a conference presentation. Also, if you just want to present (and discuss) something interesting you have found, related to your research or not, feel free to sign up. Please email Greg at grhart2@illinois.edu to get on the schedule if you would like to give a talk.