We develop an analytical tool to extract bulk electronic properties of
unconventional superconductors through inelastic neutron scattering (INS)
spectra. Since the spin excitation spectrum in the superconducting (SC) state
originates from Bogoliubov quasiparticle scattering associated with Fermi
surface nesting, its energy-momentum relation--the so called `hour-glass'
feature--can be inverted to reveal the Fermi momentum dispersion of the
single-particle spectrum as well as the corresponding SC gap function. The
inversion procedure is analogous to the quasiparticle interference (QPI) effect
in scanning tunneling microscopy (STM). Whereas angle-resolved photoemission
spectroscopy (ARPES) and STM provide surface sensitive information, our
inversion procedure provides bulk electronic properties. The technique is
essentially model independent and can be applied to a wide variety of
materials.Comment: 8 pages, 4 figure