Quantum Glass Transition in a Periodic Long-Range Josephson Array

We show that the ground state of the periodic long range Josephson array frustrated by magnetic field is a glass for a sufficiently large Josephson energies despite the absence of a quenched disorder. Like superconductors, this glass state has non-zero phase stiffness and Meissner response; for smaller Josephson energies the glass "melts" and the ground state loses the phase stiffness and becomes insulating. We find the critical scaling behavior near this quantum phase transition: the excitation gap vanishes as (J-J_c)^2, the frequency-dependent magnetic susceptibility behaves as \chi(\omega) ~ \sqrt{\omega}\ln{\omega}.