Dynamical Spectral Function From Numerical Renormalization Group: A Full Excitation Approach
arXiv:2006.16488 · doi:10.1103/PhysRevB.102.085125
Abstract
For a given quantum impurity model, Wilson's numerical renormalization group (NRG) naturally defines a NRG Hamiltonian whose exact eigenstates and eigenenergies are obtainable. We give exact expressions for the free energy, static, as well as dynamical quantities of the NRG Hamiltonian. The dynamical spectral function from this approach contains full excitations including intra- and inter-shell excitations. For the spin-boson model, we compare the spectral function obtained from the present method and the full density matrix (FDM) method, showing that while both guarantee rigorous sum rule, the full excitation approach avoids the causality problem of FDM method.
9 pages and 8 figures
References in corpus (9)
- The numerical renormalization group method for quantum impurity systems
- Real-time dynamics in Quantum Impurity Systems: A Time-dependent Numerical Renormalization Group Approach
- Sum-rule Conserving Spectral Functions from the Numerical Renormalization Group
- Energy resolution and discretization artefacts in the numerical renormalization group
- Numerical Renormalization Group for Bosonic Systems and Application to the Subohmic Spin-Boson Model
- A Numerical Renormalization Group approach to Green's Functions for Quantum Impurity Models
- Spin Precession and Real Time Dynamics in the Kondo Model: A Time-Dependent Numerical Renormalization-Group Study
- Matrix product state comparison of the numerical renormalization group and the variational formulation of the density matrix renormalization group
- Equilibrium Dynamics of the Sub-Ohmic Spin-boson Model Under Bias