Zobrazeno 1 - 5
of 5
pro vyhledávání: '"Markku Hyrkäs"'
For a given diagrammatic approximation in many-body perturbation theory it is not guaranteed that positive observables, such as the density or the spectral function, retain their positivity. For zero-temperature systems we developed a method [2014 Ph
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::25f16696beb1e747aa1762cf7a657bca
http://urn.fi/URN:NBN:fi:jyu-202208254337
http://urn.fi/URN:NBN:fi:jyu-202208254337
In non-equilibrium many-body perturbation theory, Langreth rules are an efficient way to extract real-time equations from contour ones. However, the standard rules are not applicable in cases that do not reduce to simple convolutions and multiplicati
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::fd2751fc47fd4181b6295530d9a04d8d
http://urn.fi/URN:NBN:fi:jyu-202208314416
http://urn.fi/URN:NBN:fi:jyu-202208314416
Recently, a method was presented for constructing self-energies within many-body perturbation theory that are guaranteed to produce a positive spectral function for equilibrium systems, by representing the self-energy as a product of half-diagrams on
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::27508e4d5fd3cb46312b923d27296253
http://urn.fi/URN:NBN:fi:jyu-202001081106
http://urn.fi/URN:NBN:fi:jyu-202001081106
Publikováno v:
Physical Review A. 87
The difference between boson and fermion dynamics in quasi-one-dimensional lattices is studied by calculating the persistent current in small quantum rings and by exact simulations of the time evolution of the many-particle state in two cases: expans
Publikováno v:
Physical Review A. 82
We study atoms trapped with a harmonic confinement in an optical lattice characterized by a flat band and Dirac cones. We show that such an optical lattice can be constructed which can be accurately described with the tight binding or Hubbard models.