OSp(n|2m) quantum chains with free boundaries

In this paper we investigate the spectrum of $OSp(n|2m)$ quantum spin chains with free boundary conditions. We compute surface energy these models which, similar to other properties in thermodynamic limit including effective central charge underlying conformal field theory, depends on $n-2m$ only. For several regime $n-2m< 2$ have studied finite-size subleading logarithmic corrections scaling. As case periodic conditions find existence a tower states same dimension as identity operator. expected amplitudes corresponding differ from those found previously for point out however simple relations connecting such and boundaries. Based our findings formulate conjecture long distance behaviour bulk watermelon correlators.