Relaxation of nuclear spin in atomic hydrogen due to long-range orbital currents in metal walls

Thermal current fluctuations in bulk metal produce a fluctuating magnetic field that extends outside the metal’s surface. We find that its spectral density 〈H(z${)}^2$${\mathrm{〉}}_{\mathrm{\omega }}$ as a function of distance from the surface decays as ln(z) at distances less than the mean free path of the electrons in the metal and as 1/z at large z. We evaluate the nuclear-spin relaxation rate due to these fluctuations. We apply our model to the one-body surface relaxation rate of atomic hydrogen. We find the relaxation time to be of the order of ${10}^3$ s at a temperature of 1 K. A possible relaxation mechanism due to electric-field fluctuations, which may also be applicable to cells with insulating walls, is discussed.