  A method for analytic continuation of imaginary-time correlation functions
(here obtained in quantum Monte Carlo simulations) to real-frequency spectral
functions is proposed. Stochastically sampling a spectrum parametrized by a
large number of delta-functions, treated as a statistical-mechanics problem, it
avoids distortions caused by (as demonstrated here) configurational entropy in
previous sampling methods. The key development is the suppression of entropy by
constraining the spectral weight to within identifiable optimal bounds and
imposing a set number of peaks. As a test case, the dynamic structure factor of
the S=1/2 Heisenberg chain is computed. Very good agreement is found with Bethe
Ansatz results in the ground state (including a sharp edge) and with exact
diagonalization of small systems at elevated temperatures.
