Nature of order from random two-body interactions

We investigate the origin of order in the low-lying spectra of many-body sy stems with random two-body interactions. Our study based both on analytical as well as on numerical arguments shows that except for the most J-stretch ed states, the ground states in the higher J-sectors are more orderly and d evelop larger energy gaps than the ones in the J = 0-sector. Due to differe nt characteristic energy scales in different J-sectors the J = 0 ground sta tes may predominate only when all the states are taken together. (C) 2001 E lsevier Science B.V. All rights reserved.