Full density-matrix numerical renormalization group calculation of impurity susceptibility and specific heat of the Anderson impurity model

Merker, L.; Weichselbaum, A.; Costi, T.A.

doi:10.1103/PhysRevB.86.075153

Journal Article

Full density-matrix numerical renormalization group calculation of impurity susceptibility and specific heat of the Anderson impurity model

Merker, L.FZJ* ; Weichselbaum, A. ; Costi, T. A.FZJ*

2012
APS College Park, Md.

Physical review / B 86(7), 075153 (2012) [10.1103/PhysRevB.86.075153]

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Please use a persistent id in citations: http://hdl.handle.net/2128/10845 doi:10.1103/PhysRevB.86.075153

Abstract: Recent developments in the numerical renormalization group (NRG) allow the construction of the full density matrix (FDM) of quantum impurity models [see A. Weichselbaum and J. von Delft, Phys. Rev. Lett. 99, 076402 (2007)] by using the completeness of the eliminated states introduced by F. B. Anders and A. Schiller [F. B. Anders and A. Schiller, Phys. Rev. Lett. 95, 196801 (2005)]. While these developments prove particularly useful in the calculation of transient response and finite-temperature Green's functions of quantum impurity models, they may also be used to calculate thermodynamic properties. In this paper, we assess the FDM approach to thermodynamic properties by applying it to the Anderson impurity model. We compare the results for the susceptibility and specific heat to both the conventional approach within NRG and to exact Bethe ansatz results. We also point out a subtlety in the calculation of the susceptibility (in a uniform field) within the FDM approach. Finally, we show numerically that for the Anderson model, the susceptibilities in response to a local and a uniform magnetic field coincide in the wide-band limit, in accordance with the Clogston-Anderson compensation theorem.

Keyword(s): J

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Physics, Condensed Matter

Note: We thank Jan von Delft, Markus Hanl, and Ralf Bulla for useful discussions and acknowledge supercomputer support by the John von Neumann institute for Computing (Julich). Support from the DFG under grant number WE4819/1-1 is also acknowledged (AW).

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