Adiabatic and local approximations for the kohn-sham potential in the hubbard model

Mancini, Lorenzo (2013) Adiabatic and local approximations for the kohn-sham potential in the hubbard model. [Laurea magistrale], Università di Bologna, Corso di Studio in Fisica [LM-DM270]
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We obtain the exact time-dependent Kohn-Sham potentials Vks for 1D Hubbard chains, driven by a d.c. external field, using the time-dependent electron density and current density obtained from exact many-body time-evolution. The exact Vxc is compared to the adiabatically-exact Vad-xc and the “instantaneous ground state” Vigs-xc. The effectiveness of these two approximations is analyzed. Approximations for the exchange-correlation potential Vxc and its gradient, based on the local density and on the local current density, are also considered and both physical quantities are observed to be far outside the reach of any possible local approximation. Insight into the respective roles of ground-state and excited-state correlation in the time-dependent system, as reflected in the potentials, is provided by the pair correlation function.

Tipologia del documento
Tesi di laurea (Laurea magistrale)
Autore della tesi
Mancini, Lorenzo
Relatore della tesi
Corso di studio
Curriculum C: Fisica della materia
Ordinamento Cds
Parole chiave
Time-dependent density functional theory, Hubbard model, Adiabatic approximation, electronic correlation
Data di discussione della Tesi
18 Ottobre 2013

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