  We use a variational method to calculate the spectrum and the parton
distribution function of ground state hadrons of various gauge theories in 1+1
dimensions. The template functions in our method minimize a free energy
functional defined as a combination of free valence partons' kinetic energy on
the lightcone and the Renyi entanglement entropy of biparton subsystems. Our
results show that hadrons in these theories minimize the proposed free energy.
The success of this technique motivates applying it to confining gauge theories
in higher dimensions.
