3 years ago

A real-time extension of density matrix embedding theory for non-equilibrium electron dynamics.

Garnet Kin-Lic Chan, Joshua S. Kretchmer

We introduce real-time density matrix embedding theory (DMET), a dynamical quantum embedding theory for computing non-equilibrium electron dynamics in strongly correlated systems. As in the previously developed static DMET, real-time DMET partitions the system into an impurity corresponding to the region of interest coupled to the surrounding environment, which is efficiently represented by a quantum bath of the same size as the impurity. In this work, we focus on a single-impurity time-dependent theory as a first step towards a full multi-impurity theory. The equations of motion of the coupled impurity and bath embedding problem in real-time DMET are then derived using the time-dependent variational principle. The accuracy of real-time DMET is compared to that of time-dependent complete active space self-consistent field (TD-CASSCF) theory and time-dependent Hartree-Fock (TDHF) theory for a variety of quantum quenches in the single impurity Anderson model (SIAM), in which the Hamiltonian is suddenly changed (quenched) to induce a non-equilibrium state. Real-time DMET shows a marked improvement over the meanfield TDHF, converging to the exact answer even in the non-trivial Kondo regime of the SIAM. However, as in static DMET, the increased dynamic flexibility of TD-CASSCF in comparison to real-time DMET using a single impurity leads to faster convergence with respect to active space size. Our results demonstrate that real-time DMET is an efficient method well suited for the simulation of non-equilibrium electron dynamics in which strong electron correlation plays an important role.

Publisher URL: http://arxiv.org/abs/1609.07678

DOI: arXiv:1609.07678v2

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.