Excitons in a quantum wire subjected to a magnetic field

We present variational calculations of the ground-state exciton binding energy and exciton radius in a quantum wire subjected to an external magnetic field. The magnetic field squeezes the exciton wave function, causing the binding energy to become very large and increase superlinearly with the field; at the same time, the exciton radius shrinks. The squeezing is more effective in wider wires, where the exciton wave function is ‘‘softer.’’ These results are consistent with recently reported experimental observations.