Form factors approach to current correlations in onedimensional systems with impurities
Abstract
We show how to compute analytically time and space dependent correlations in onedimensional quantum integrable systems with an impurity. Our approach is based on a description of these systems in terms of massless scattering of quasiparticles. Correlators follow then from matrix elements of local operators between multiparticle states, the "massless form factors". Although an infinite sum of these form factors has to be considered in principle, we find that for current, spin, and energy operators, only a few (typically two or three) are necessary to obtain an accuracy of more than 1%, for arbitrary coupling strength, that is all the way from short to large distances. As examples we compute, at zero temperature, the frequencydependent conductance in a Luttinger liquid with impurity, the spectral function in the doublewell problem of dissipative quantum mechanics and part of the spacedependent susceptibility in the Kondo model.
 Publication:

Nuclear Physics B
 Pub Date:
 February 1996
 DOI:
 10.1016/05503213(96)002349
 arXiv:
 arXiv:condmat/9603043
 Bibcode:
 1996NuPhB.474..602L
 Keywords:

 Condensed Matter;
 High Energy Physics  Theory
 EPrint:
 2 References corrected, three added. Discussion of the Screening cloud modified. 42 pages, harvmac, epsf and 6 figures