Lifetime of magnetically trapped ultracold atomic deuterium gas

We have calculated the magnetic dipolar spin-relaxation rates of magnetically trapped doubly-spin-polarized atomic deuterium gas. The results are expressed in a simple closed formula describing the dipolar-relaxation-limited stability in the Boltzmann ($T\gg T_F$), the degeneracy ($T\ll T_F$), and the crossover ($T\simeq T_F$) regimes. In the degeneracy regime we typically find lifetimes of some hours. We also discuss the dipolar decay of magnetically trapped spin-polarized fermionic alkali-metal atoms.