% IMPORTANT: The following is UTF-8 encoded. This means that in the presence % of non-ASCII characters, it will not work with BibTeX 0.99 or older. % Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or % “biber”. @ARTICLE{Nghiem:852913, author = {Nghiem, H. T. M. and Costi, Theodoulos}, title = {{T}ime-dependent numerical renormalization group method for multiple quenches: {T}owards exact results for the long-time limit of thermodynamic observables and spectral functions}, journal = {Physical review / B}, volume = {98}, number = {15}, issn = {2469-9950}, address = {Woodbury, NY}, publisher = {Inst.}, reportid = {FZJ-2018-05700}, pages = {155107}, year = {2018}, abstract = {We develop an alternative time-dependent numerical renormalization group (TDNRG) formalism for multiple quenches and implement it to study the response of a quantum impurity system to a general pulse. Within this approach, we reduce the contribution of the NRG approximation to numerical errors in the time evolution of observables by a formulation that avoids the use of the generalized overlap matrix elements in our previous multiple-quench TDNRG formalism [Nghiem et al., Phys. Rev. B 89, 075118 (2014); Phys. Rev. B 90, 035129 (2014)]. We demonstrate that the formalism yields a smaller cumulative error in the trace of the projected density matrix as a function of time and a smaller discontinuity of local observables between quenches than in our previous approach. Moreover, by increasing the switch-on time, the time between the first and last quench of the discretized pulse, the long-time limit of observables systematically converges to its expected value in the final state, i.e., the more adiabatic the switching, the more accurately is the long-time limit recovered. The present formalism can be straightforwardly extended to infinite switch-on times. We show that this yields highly accurate results for the long-time limit of both thermodynamic observables and spectral functions, and overcomes the significant errors within the single quench formalism [Anders et al., Phys. Rev. Lett. 95, 196801 (2005); Nghiem et al., Phys. Rev. Lett. 119, 156601 (2017)]. This improvement provides a first step towards an accurate description of nonequilibrium steady states of quantum impurity systems, e.g., within the scattering states NRG approach [Anders, Phys. Rev. Lett. 101, 066804 (2008)].}, cin = {IAS-3 / JARA-HPC}, ddc = {530}, cid = {I:(DE-Juel1)IAS-3-20090406 / $I:(DE-82)080012_20140620$}, pnm = {142 - Controlling Spin-Based Phenomena (POF3-142) / Thermoelectric properties of molecular quantum dots and time-dependent response of quantum dots $(jiff23_20140501)$}, pid = {G:(DE-HGF)POF3-142 / $G:(DE-Juel1)jiff23_20140501$}, typ = {PUB:(DE-HGF)16}, UT = {WOS:000446296600003}, doi = {10.1103/PhysRevB.98.155107}, url = {https://juser.fz-juelich.de/record/852913}, }