Ground state of a hydrogen molecule in superstrong magnetic fields

We study the ground-state structural properties of a hydrogen molecule in superstrong magnetic fields (B≊${10}^{12}$ G) using quantum Monte Carlo (fixed-phase and variational) approaches. We determine that the ground state (spin-triplet) belongs to the sector of total (z-component) angular momentum M=-1 ${(}^3$ ${\mathrm{\Pi }}_0$), meaning that paramagnetic contributions to the total energy cannot be neglected. This non-time-reversal invariant ground state has a strong interatomic interaction, suggesting that a hydrogen gas under the same physical conditions has a tendency to form strong bonded molecules.