2006/11/30 by Andreas Friedrich, A. Friedrich, A. K. Kolezhuk +4 · 1 citation
Physics and Astronomy · #Advanced Condensed Matter Physics #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.75.094414
published as Phys. Rev. B 75, 094414 (2007) · (v2) error in Eq.(11) corrected
arxiv created 2007/02/12 · openalex publication_date 2007/03/13 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We use the dynamical density matrix renormalization group technique to show that the high-energy part of the spectrum of an S=1 Heisenberg chain, placed in a strong external magnetic field H exceeding the Haldane gap \ensuremathΔ, contains edge singularities, similar to those known to exist in the low-energy spectral response. It is demonstrated that in the frequency range \ensuremathω\ensuremath\gtrsim\ensuremathΔ the longitudinal (with respect to the applied field) dynamical structure factor is dominated by the power-law singularity S^\ensuremath\Vert(q=\ensuremathπ,\ensuremathω)\ensuremath∝(\ensuremathω\ensuremath-\ensuremathω0)^\ensuremath-\ensuremathα^\ensuremath'. We study the behavior of the high-energy edge exponent \ensuremathα^\ensuremath' and the edge \ensuremathω0 as functions of the magnetic field. The existence of edge singularities at high energies is directly related to the Tomonaga-Luttinger liquid character of the ground state at H>\ensuremathΔ and is expected to be a general feature of one-dimensional gapped spin systems in high magnetic fields.