Zobrazeno 1 - 10
of 72
pro vyhledávání: '"Gunacker, P."'
Publikováno v:
Phys. Rev. B 100, 075119 (2019)
We derive equations of motion for Green's functions of the multi-orbital Anderson impurity model by differentiating symmetrically with respect to all time arguments. The resulting equations relate the one- and two-particle Green's function to correla
Externí odkaz:
http://arxiv.org/abs/1906.00880
Publikováno v:
Phys. Rev. Lett. 122, 127601 (2019)
We present a dynamical mean-field study of dynamical susceptibilities in two-band Hubbard model. Varying the model parameters we analyze the two-particle excitations in the normal as well as in the ordered phase, an excitonic condensate. The two-part
Externí odkaz:
http://arxiv.org/abs/1808.08046
Autor:
Kowalski, Alexander, Hausoel, Andreas, Wallerberger, Markus, Gunacker, Patrik, Sangiovanni, Giorgio
Publikováno v:
Phys. Rev. B 99, 155112 (2019)
Due to the intrinsic complexity of the quantum many-body problem, quantum Monte Carlo algorithms and their corresponding Monte Carlo configurations can be defined in various ways. Configurations corresponding to few Feynman diagrams often lead to sev
Externí odkaz:
http://arxiv.org/abs/1807.00361
Publikováno v:
Phys. Rev. B 98, 125106 (2018)
The dual fermion (DF) method allows for calculating corrections due to non-local correlations relative to an effective impurity model. Choosing the impurity as that of a dynamical mean field theory (DMFT) solution at self-consistency is popular, and
Externí odkaz:
http://arxiv.org/abs/1805.10996
Autor:
Wallerberger, Markus, Hausoel, Andreas, Gunacker, Patrik, Kowalski, Alexander, Parragh, Nicolaus, Goth, Florian, Held, Karsten, Sangiovanni, Giorgio
Publikováno v:
Comput. Phys. Commun. 235, 388-399 (2019)
We describe the hybridization-expansion continuous-time quantum Monte Carlo code package "w2dynamics", developed in Wien and W\"urzburg. We discuss the main features of this multi-orbital quantum impurity solver for the Anderson impurity model, dynam
Externí odkaz:
http://arxiv.org/abs/1801.10209
Publikováno v:
Phys. Rev. B 97, 245136 (2018)
In this work, we analyze in detail the occurrence of divergences in the irreducible vertex functions for one of the fundamental models of many-body physics: the Anderson impurity model (AIM). These divergences -- a surprising hallmark of the breakdow
Externí odkaz:
http://arxiv.org/abs/1712.04171
Autor:
Ribic, T., Gunacker, P., Iskakov, S., Wallerberger, M., Rohringer, G., Rubtsov, A. N., Gull, E., Held, K.
Publikováno v:
Phys. Rev. B 96, 235127 (2017)
We investigate the influence of self-energy diagrams beyond the two-particle vertex level within dual fermion theory. Specifically, we calculate the local three-particle vertex and construct from it selected dual fermion self-energy corrections to dy
Externí odkaz:
http://arxiv.org/abs/1710.00648
While key effects of the many-body problem---such as Kondo and Mott physics---can be understood in terms of on-site correlations, non-local fluctuations of charge, spin, and pairing amplitudes are at the heart of the most fascinating and unresolved p
Externí odkaz:
http://arxiv.org/abs/1709.02663
Publikováno v:
Phys. Rev. B 96, 035114 (2017)
We derive the equations for calculating the high-frequency asymptotics of the local two-particle vertex function for a multi-orbital impurity model. These relate the asymptotics for a general local interaction to equal-time two-particle Green's funct
Externí odkaz:
http://arxiv.org/abs/1703.09407
The mass-imbalanced Hubbard model represents a continuous evolution from the Hubbard to the Falicov-Kimball model. We employ dynamical mean field theory and study the paramagnetic metal-insulator transition, which has a very different nature for the
Externí odkaz:
http://arxiv.org/abs/1611.10079