Open Wilson chains for quantum impurity models: Keeping track of all bath modes

Bruognolo, B.; Linden, N.-O.; Schwarz, F.; Lee, S.-S. B.; Stadler, K.; Weichselbaum, A.; Vojta, M.; Anders, F. B.; Delft, J. von (2017): Open Wilson chains for quantum impurity models: Keeping track of all bath modes. In: Physical Review B, Vol. 95, No. 12, 121115

Abstract

When constructing a Wilson chain to represent a quantum impurity model, the effects of truncated bath modes are neglected. We show that their influence can be kept track of systematically by constructing an "open Wilson chain" in which each site is coupled to a separate effective bath of its own. As a first application, we use the method to cure the so-calledmass-flow problem that can arise when using standard Wilson chains to treat impurity models with asymmetric bath spectral functions at finite temperature. We demonstrate this for the strongly sub-Ohmic spin-boson model at quantum criticality where we directly observe the flow towards a Gaussian critical fixed point.

• Item Type: Journal article
• Faculties: Physics
• Research Centers: Center for NanoScience (CENS)
• Subjects: 500 Science > 530 Physics; 500 Science > 500 Science
• ISSN: 2469-9950
• Language: English