Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 80: Correlated Electrons: (General) Theory 2
TT 80.6: Vortrag
Donnerstag, 10. März 2016, 17:30–17:45, H18
Nature of the many-body excitations in a quantum wire — •Oleksandr Tsyplyatyev — Institut für Theoretische Physik, Universität Frankfurt, Frankfurt, Germany
The natural excitations of an interacting one-dimensional system at low energy are hydrodynamic modes of Luttinger liquid, protected by the Lorentz invariance of the linear dispersion. We show that beyond low energies, where quadratic dispersion reduces the symmetry to Galilean, the main character of the many-body excitations changes into a hierarchy: calculations of dynamic correlation functions for fermions (without spin) show that the spectral weights of the excitations are proportional to powers of R2/L2, where R is a length-scale related to interactions and L is the system length. Thus only small numbers of excitations carry the principal spectral power in representative regions on the energy-momentum planes. We have analysed the spectral function in detail and have shown that the first-level (strongest) excitations form a mode with parabolic dispersion, like that of a renormalised single particle. The second-level excitations produce a singular power-law line shape to the first-level mode and multiple power-laws at the spectral edge. We have illustrated crossover to Luttinger liquid at low energy by calculating the local density of state through all energy scales: from linear to non-linear, and to above the chemical potential energies.
O. Tsyplyatyev et al., PRL 114, 196401 (2015).
O. Tsyplyatyev et al., arXiv:1508.07125.