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Some theoretical studies using perturbation and tight-binding methods have tried to shed light on the magnetic behaviors of carbon-based nanostructures in the limit of wave vector q = 0 . In a recent work, we studied a half-filled model of helical carbon chains to gain new insights for q ≠ 0 . Although in carbon the energy bands are usually derived from partially filled atomic p-shells, here we explore the hole contribution to these magnetic responses. We calculate the longitudinal spin susceptibility of an almost-filled tight-binding model of a helical chain for q ≠ 0 . We find that when the Fermi level lies at the band edges, the system shows for positive chirality a divergent paramagnetic susceptibility. This result is in agreement with that previously reported for the macroscopic limit q = 0 . [ABSTRACT FROM AUTHOR]

We have loaded spin-polarized hydrogen (SPH) into a magnetostatic Ioffe trap with central fields as high as 1 T and at two different temperatures, 0.25 and 0.4 K, on the way to create a gas of SPH with two distinguishable Bose component. We have measured the magnetic dipole decay rate constant of SPH at these high fields and found good agreement with theory. A measurement technique that allows determination of the absolute number of atoms was developed. [ABSTRACT FROM AUTHOR]