Dresden 2009 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 6: Postersession Correlated Electrons: (General) Theory, Low-Dimensional Systems, Kondo Physics, Heavy Fermions, Quantum-Critical Phenomena

TT 6.61: Poster

Montag, 23. März 2009, 13:00–16:45, P1A

Longitudinal magnon decay near a quantum critical point — •Lucas Hollender and Matthias Vojta — Institut für theoretische Physik, Universiät zu Köln, Köln, Deutschland

A spin dimer system shows a zero-field magnetic order-disorder transition at a critical ratio of the inter-dimer to intra-dimer couplings. We investigate the decay process of the longitudinal magnon in the antiferromagnetic phase, which has been observed in neutron scattering experiments, as function of the distance to the quantum phase transition. We employ a perturbative analysis within a modified bond operator formalism to compute the lifetime of the longitudinal mode and compare the results to recent neutron scattering measurements on TlCuCl₃.