Finite temperature correlations in the onedimensional quantum Ising model
Abstract
We extend the formfactors approach to the quantum Ising model at finite temperature. The twopoint function of the energy is obtained in closed form, while the twopoint function of the spin is written as a Fredholm determinant. Using the approach of Korepin et al., we obtain, starting directly from the continuum formulation, a set of six differential equations satisfied by this twopoint function. Four of these equations involve only spacetime derivatives, of which three are equivalent to the equations obtained earlier. In addition, we obtain two new equations involving a temperature derivative. Some of these results are generalized to the Ising model on the half line with a magnetic field at the origin.
 Publication:

Nuclear Physics B
 Pub Date:
 February 1996
 DOI:
 10.1016/S05503213(96)004567
 arXiv:
 arXiv:condmat/9606104
 Bibcode:
 1996NuPhB.482..579L
 Keywords:

 Condensed Matter;
 High Energy Physics  Theory
 EPrint:
 37 pages, uses harvmac, minor changes in the last two paragraphs, updating some conjectures