Doctoral Dissertation

1.3.2019 M.Sc. Luis Cort Barrada (Faculty of Mathematics and Science, The Department of Physics)


1.3.2019 12:00 — 16:00

Location: Ylistonrinne , FYS1
Release: 1.3.2019 Time-dependent density-functional theory for strongly correlated electrons
One of the most used methods in condensed matter theory and quantum chemistry for the description of matter properties is Time-dependent density-functional theory (TDDFT), an alternative formalism to wave function methods which uses the time-dependent electronic density for the determination of any quantum average of an electronic system. In his dissertation M.Sc Luis Cort Barrada has tested Time-dependent density-functional theory with SCE density functionals which describe physics of strongly interacting electrons.

 The usual approach in TDDFT is by means a non-interacting system, where all the interaction effects are encoded in an effective one-body potential that exactly reproduces the time-dependent density of any interacting system. The effective potential is called the exchange-correlation (xc) potential.

For the calculation of the excited states in TDDFT, one needs the knowledge of theexchange-correlation potential and its functional derivative with respect to the density, which is known as the exchange-correlation kernel. For practical applications, both theexchange-correlation potential and the exchange-correlation kernel needs to be approximated. 

In the last years, better approximations for the exchange-correlation potential and kernel have been constructed, but it turns out that the usual approximations fail for the description of strongly correlated systems.

Recently, a new type of density functionals, the strictly correlated electrons (SCE) formalism have been constructed with the aim to describe the physics of strongly correlated systems, but not tested so far for the obtaining of excitation energies. 

One way to gain insight and test the performance of the density functionals is to compare them against exact expressions obtained from exactly solvable systems. In this work, we construct such strongly correlated systems, and we solve them exactly for the subsequent comparison with the predictions provided by the SCE density functionals. The comparison of the results, therefore, will provide insights of the applicability of this kind of density functionals, establishing in this way its range of validity.

SCE density functional can describe the physics of a strongly interacting system but fails for the description of the physics of a dissociating molecule.

M.Sc. Luis Cort Barrada defends his doctoral dissertation in Subject "Time-dependent density-functional theory for strongly correlated electrons".  Opponent is Professor Stefan Kurth (University of the Basque Country/Donostia International Physics Center) and Custos is Professor Robert van Leeuwen (University of Jyväskylä). The doctoral dissertation is held in English.

The disseration is published in the JYU Dissertations series, University of Jyväskylä; 61, ISSN 2489-9003; 61. 

Link to publication: ISBN: 978-951-39-7687-3

More information:

M.Sc. Luis Cort Barrada,

Comminications officer Tanja Heikkinen,, tel. 0505818351







More information

Luis Cort Barrada

Doctoral Student

Faculty of Mathematics and Science, The Department of Physics