title: Theory of the optical conductivity of spin liquid states in one-dimensional Mott insulators.
abstract: The low-energy dynamical optical response of dimerized and undimerized spin liquid states in a one-dimensional charge transfer Mott insulator is theoretically studied. An exact analysis is given for the low-energy asymptotic behavior using conformal field theory for the undimerized state. In the dimerized state, the infrared absorption due to the bound state of two solitons, i.e., the breather mode, is predicted with an accurate estimate for its oscillator strength, offering a way to detect experimentally the excited singlet state. The effects of external magnetic fields are also discussed.
authors.affiliation: Cross-Correlated Materials T. Research Group (CMRG), RIKEN, Saitama, Wako 351-0198, Japan.
authors.forename: Hosho
authors.initials: H
authors.lastname: Katsura
authors.forename: Masahiro
authors.initials: M
authors.lastname: Sato
authors.forename: Takashi
authors.initials: T
authors.lastname: Furuta
authors.forename: Naoto
authors.initials: N
authors.lastname: Nagaosa