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The mass-flow error in the Numerical Renormalization Group method and the critical behavior of the sub-ohmic spin-boson model
Matthias Vojta, Ralf Bulla, Fabian Guettge +1
We discuss a particular source of error in the Numerical Renormalization Group (NRG) method for quantum impurity problems, which is related to a renormalization of impurity paramet…
The quantum phase transition in the sub-ohmic spin-boson model: Quantum Monte-Carlo study with a continuous imaginary time cluster algorithm
Andre Winter, Heiko Rieger, Matthias Vojta +1
A continuous time cluster algorithm for two-level systems coupled to a dissipative bosonic bath is presented and applied to the sub-ohmic spin-Boson model. When the power s of the…
Equilibrium and non-equilibrium dynamics of the sub-ohmic spin-boson model
Frithjof B. Anders, Ralf Bulla, Matthias Vojta
Employing the non-perturbative numerical renormalization group method, we study the dynamics of the spin-boson model, which describes a two-level system coupled to a bosonic bath w…
Quantum Phase Transitions in the Bosonic Single-Impurity Anderson Model
Hyun-Jung Lee, Ralf Bulla
We consider a quantum impurity model in which a bosonic impurity level is coupled to a non-interacting bosonic bath, with the bosons at the impurity site subject to a local Coulomb…
Quantum phase transitions in the sub-ohmic spin-boson model: Failure of the quantum-classical mapping
Matthias Vojta, Ning-Hua Tong, Ralf Bulla
The effective theories for many quantum phase transitions can be mapped onto those of classical transitions. Here we show that such a mapping fails for the sub-ohmic spin-boson mod…
Numerical Renormalization Group for Bosonic Systems and Application to the Subohmic Spin-Boson Model
Ralf Bulla, Ning-Hua Tong, Matthias Vojta
We describe the generalization of Wilson's Numerical Renormalization Group method to quantum impurity models with a bosonic bath, providing a general non-perturbative approach to b…