title: Electron spin resonance in sine-gordon spin chains in the perturbative spinon regime.
abstract: We report the low-temperature multifrequency ESR studies of copper pyrimidine dinitrate, a spin-1/2 antiferromagnetic chain with alternating g tensor and the Dzyaloshinskii-Moriya interaction, allowing us to test a new theoretical concept proposed recently by Oshikawa and Affleck [Phys. Rev. Lett. 82, 5136 (1999)]. Their theory, based on bosonization and self-energy formalism, can be applied for precise calculation of ESR parameters of S=1/2 antiferromagnetic chains in the perturbative spinon regime. Excellent quantitative agreement between the theoretical predictions and experiment is obtained.
authors.affiliation: Hochfeld-Magnetlabor Dresden, Forschungszentrum Rossendorf, 01328 Dresden, Germany.
authors.forename: S A
authors.initials: SA
authors.lastname: Zvyagin
authors.forename: A K
authors.initials: AK
authors.lastname: Kolezhuk
authors.forename: J
authors.initials: J
authors.lastname: Krzystek
authors.forename: R
authors.initials: R
authors.lastname: Feyerherm