Threshold singularities in the dynamic response of gapless integrable models.
We develop a method of an asymptotically exact treatment of threshold singularities in dynamic response functions of gapless integrable models. The method utilizes the integrability to recast the original problem in terms of the low-energy properties of a certain deformed Hamiltonian. The deformed Hamiltonian is local; hence, it can be analyzed using the conventional field theory methods. We apply the technique to spinless fermions on a lattice with nearest-neighbors repulsion, and evaluate the exponent characterizing the threshold singularity in the dynamic structure factor.
Cheianov
Vadim V
VV
Physics Department, Lancaster University, Lancaster LA1 4YB, United Kingdom.
Pustilnik
Michael
M