1112.0737 (B. Mansart et al.)

Coupling of paired quasiparticles to a non-retarded interaction in a
high-Tc cuprate    [PDF]

B. Mansart, J. Lorenzana, A. Mann, A. Odeh, M. Scarongella, M. Chergui, F. Carbone

Dynamical information of spin degrees of freedom of proteins or solids can be obtained by nuclear magnetic resonance (NMR). A technique with similar versatility for charge degrees of freedom and their ultrafast correlations could move forward the understanding of systems like high-T_c materials. By perturbing the superconducting state in a cuprate using a femtosecond laser pulse we generate coherent oscillations of the Cooper pairs which can be described by an NMR formalism. The oscillations are detected by transient broad-band reflectivity and found to resonate at the typical scale of Mott physics (2.6 eV) implying a substantial contribution of non-retarded interactions to the pairing interaction, as in unconventional (non Migdal-Eliashberg) theories.

View original: http://arxiv.org/abs/1112.0737