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Caltech

IQIM Postdoctoral and Graduate Student Seminar

Friday, December 8, 2023
12:00pm to 1:00pm
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East Bridge 114
Data-driven compression of electron-phonon interactions
Yao Luo, Bernardi Group,

Abstract: First-principles calculations of electron interactions in materials have seen rapid progress in recent years, with electron-phonon (e-ph) interactions being a prime example. However, these techniques use large matrices encoding the interactions on dense momentum grids, which reduces computational efficiency and obscures interpretability. For e-ph interactions, existing interpolation techniques leverage locality in real space, but the high dimensionality of the data remains a bottleneck to balance cost and accuracy. Here we show an efficient way to compress e-ph interactions based on singular value decomposition (SVD), a widely used matrix / image compression technique. Leveraging (un)constrained SVD methods, we accurately predict material properties related to e-ph interactions - including charge mobility, spin relaxation times, band renormalization, and superconducting critical temperature - while using only a small fraction (1-2%) of the interaction data. These findings unveil the hidden low-dimensional nature of e-ph interactions. Furthermore, they accelerate state-of-the-art first-principles e-ph calculations by about two orders of magnitudes without sacrificing accuracy. Our Pareto-optimal parametrization of e-ph interactions can be readily generalized to electron-electron and electron-defect interactions, as well as to other couplings, advancing quantitative studies of condensed matter.

In addition, this compression method enables new calculations, which are numerically unaffordable before. As an example, I will show first-principles diagrammatic Monte Carlo simulations of polarons in real materials.

Lunch will be provided, following the talk, on the lawn north of the Bridge Building.

For more information, please contact Marcia Brown by phone at 626-395-4013 or by email at [email protected].