Finite size corrections to scaling of the formation probabilities and   the Casimir effect in the conformal field theories
  We calculate formation probabilities of the ground state of the finite size quantum critical chains using conformal field theory (CFT) techniques. In particular, we calculate the formation probability of one interval in the finite open chain and also formation probability of two disjoint intervals in a finite periodic system. The presented formulas can be also interpreted as the Casimir energy of needles in particular geometries. We numerically check the validity of the exact CFT results in the case of the transverse field Ising chain. 
M. A. Rajabpour
cond-mat.stat-mech cond-mat.str-el