arXiv subjects

E. K. U. Gross

Publications and source records attributed to E. K. U. Gross.

168 records · Page 10Linked to original sources

arXiv2001

Relativistic Theory of Superconductivity

The relativistic generalization of the theory of superconductivity is reviewed with respect to its conceptual basis and first applications. The construction of relativistically covariant order parameters for superconductors is outlined and the generalization of the Dirac equation for the superconducting state is presented. A weakly relativistic expansion of this equation leads to the Pauli equation for superconductors, which describes the lowest-order relativistic corrections to the conventional theory of superconductivity. The physics of these corrections is discussed, and the prospects for experimental detection of relativistic effects in superconductors are examined.

cond-mat.soft↗

arXiv2000

A hybrid functional for the exchange-correlation kernel in time-dependent density functional theory

A review of the approximations in any time-dependent density functional calculation of excitation energies is given. The single-pole approximation for the susceptibility is used to understand errors in popular approximations for the exchange-correlation kernel. A new hybrid of exact exchange and adiabatic local density approximation is proposed and tested on the He and Be atoms.

cond-mat.mtrl-sci↗

arXiv2000

Excitation energies from time-dependent density functional theory using exact and approximate functionals

The role of the exchange-correlation potential and the exchange-correlation kernel in the calculation of excitation energues from time-dependent density functional theory is studied. Excitation energies of the He and Be atoms are calculated, both from the exact ground-state Kohn-Sham potential, and from two orbital-dependent approximations. These are exact exchange and self-interaction corrected local density approximation (SIC-LDA), both calculated using the Krieger-Li-Iafrate (KLI) approximation. For the exchange-correlation kernela, three adiabatic approximations were tested: The local density approximation, exact exchange, and SIC-LDA. The choice of the ground-state exchange-correlation potential has the largest impact on the absolute position of most excitation energies. In particular, orbital-dependent approximate potentials result in a uniform shift of the transition energies to the Rydberg states.

cond-mat.mtrl-sci↗

arXiv1996

Applications of the Optimized Effective Potential Method of Density Functional Theory to Atomic and Molecular Systems

Using the optimized effective potential method in conjunction with the semi-analytical approximation due to Krieger, Li and Iafrate, we have performed fully self-consistent exact exchange-only density-functional calculations for diatomic molecules with a fully numerical basis-set-free molecular code. The results are very similar to the ones obtained with the Hartree Fock approach. Furthermore we present results for ground states of positive atomic ions including correlation contributions in the approximation of Colle and Salvetti. It is found that the scheme performs significantly better than conventional Kohn-Sham calculations.

chem-ph↗

arXiv1995

Conventional Quantum Chemical Correlation Energy versus Density-Functional Correlation Energy

We analyze the difference between the correlation energy as defined within the conventional quantum chemistry framework and its namesake in density-functional theory. Both quantities are rigorously defined concepts; one finds that $E_c^{QC} \geq E_c^{DFT}$. We give numerical and analytical arguments suggesting that the numerical difference between the two rigorous quantities is small. Finally, approximate density functional correlation energies resulting from some popular correlation energy functionals are compared with the conventional quantum chemistry values.

atom-ph↗

arXiv1995

Density functional theory using an optimized exchange-correlation potential

We have performed self-consistent calculations for first and second row atoms using a variant of density-functional theory, the optimized effective potential method, with an approximation due to Krieger, Li and Iafrate and a correlation-energy functional developed by Colle and Salvetti. The mean absolute deviation of first-row atomic ground-state energies from the exact non-relativistic values is 4.7 mH in our scheme, as compared to 4.5 mH in a recent configuration-interaction calculation. The proposed scheme is significantly more accurate than the conventional Kohn-Sham method while the numerical effort involved is about the same as for an ordinary Hartree-Fock calculation.

chem-ph↗