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TT: Tiefe Temperaturen

TT 34: Correlated Electrons - Quantum Impurities, Kondo Physics

TT 34.5: Talk

Wednesday, March 9, 2005, 10:45–11:00, TU H104

Bosonic Kondo effect of a magnetic impurity in a deconfined magnet — •Lars Fritz¹, Serge Florens¹, Matthias Vojta¹, and Kedar Damle² — ¹Institut für Theorie der Kondensierten Materie, Universität Karlsruhe,76128 Karlsruhe — ²Department of Theoretical Physics, Tata Institute of Fundamental Research, Mumbai, India

Recent works have proposed the occurrence of deconfined s=1/2 gapless bosonic degrees of freedom at the quantum critical point separating the Neel state from the valence-bond phase in some two-dimensional quantum antiferromagnets. We propose to couple such systems to a single magnetic impurity. We find within a large-N approach a quenching of the extra moment, which provides a bosonic analog to the Kondo effect in metals. This behavior is in strong contrast to the known Curie susceptibility shown in usual confining critical points, and could serve as a probe for deconfinement in critical antiferromagnets.