Ornstein-Zernike decay in the ground state of the quantum Ising model in a strong transverse field

We consider the quantum mechanical Ising ferromagnet in a strong transverse magnetic field in nay number of dimensions,d. We prove that in the ground state the power law correction to the exponential decay of the two point function isd/2. The proof begins by writing the ground state as a classical system in one more dimension. (Thus the classical Ornstein-Zernike power of (d-1)/2 becomesd/2). We then develop a convergent polymer expansion and use the techniques of Bricmont and Fröhlich [5].