280 research outputs found
Magnetization and energy dynamics in spin ladders: Evidence of diffusion in time, frequency, position, and momentum
The dynamics of magnetization and energy densities are studied in the two-leg
spin-1/2 ladder. Using an efficient pure-state approach based on the concept of
typicality, we calculate spatio-temporal correlation functions for large
systems with up to 40 lattice sites. In addition, two subsequent Fourier
transforms from real to momentum space as well as from time to frequency domain
yield the respective dynamic structure factors. Summarizing our main results,
we unveil the existence of genuine diffusion both for spin and energy. In
particular, this finding is based on four distinct signatures which can all be
equally well detected: (i) Gaussian density profiles, (ii) time-independent
diffusion coefficients, (iii) exponentially decaying density modes, and (iv)
Lorentzian line shapes of the dynamic structure factor. The combination of (i)
- (iv) provides a comprehensive picture of high-temperature dynamics in
thisarchetypal nonintegrable quantum model.Comment: 12 pages, 11 figure
Ferdinand Hamer 1840 - 1900, missiepionier en martelaar in China : een nieuwe kijk op de missiemethode van de Scheutisten in het noorden van China, en de reactie daarop van de Chinezen
UBL - phd migration 201
- …