Parameter-free analytic continuation for quantum many-body calculations

Many-body effects on graphene conductivity: Quantum Monte Carlo calculations

Parameter-free quasiparticle calculations for YH3.

Electronic structure calculations for YH3 within the local density approximation result in a metallic ground state with the bands at the Fermi energy overlapping by more than 1 eV, whereas a band gap of 2.8 eV is deduced from optical experiments. Here, we report the results of parameter-free GW calculations which predict a fundamental gap of 1 eV. When we take into account electric dipole matri...

Analytic continuation average spectrum method for quantum liquids.

We revisit the problem of determining the real-frequency density response in quantum fluids via analytical continuation of imaginary-time quantum Monte Carlo data. We demonstrate that the average spectrum method (ASM) is capable of revealing resolved modes in the dynamic structure factor of both ortho-deuterium and liquid para-hydrogen, in agreement with experiments and quantum mode-coupling th...

Many-Body Calculations of the Isotope Shift

Atomic energy levels are commonly evaluated assuming that the nuclear mass is infinite. In this report, we consider corrections to atomic levels associated with finite nuclear mass. These corrections are referred to as isotope shifts. We evaluate isotope shifts using many-body perturbation theory (MBPT), following the pioneering work by Mårtensson-Pendrill et al. [1, 2, 3, 4, 5, 6, 7, 8, 9]. We...

One-particle spectral function and analytic continuation for many-body implementation in the exact muffin-tin orbitals method

A. Östlin,1,* L. Chioncel,2,3 and L. Vitos1,4,5 1Department of Materials Science and Engineering, Applied Materials Physics, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden 2Augsburg Center for Innovative Technologies, University of Augsburg, D-86135 Augsburg, Germany 3Theoretical Physics III, Center for Electronic Correlations and Magnetism, Institute of Physics, University of A...