Fidelity susceptibility of the quantum Ising model in the transverse   field: The exact solution
  We derive an exact closed-form expression for fidelity susceptibility of the quantum Ising model in the transverse field. We also establish an exact one-to-one correspondence between fidelity susceptibility in the ferromagnetic and paramagnetic phases of this model. Elegant summation formulas are obtained as a by-product of these studies. 
Bogdan Damski
cond-mat.stat-mech cond-mat.other cond-mat.str-el quant-ph