In one powerful scene in Ron Howard’s ”A Beautiful Mind,” Jennifer Connelly says to costar Russell Crowe, ”I need to believe that something extraordinary can happen.” Well, it did. As tortured mathematician John Forbes Nash Jr. and his loyal wife Alicia, Crowe and Connelly not only age convincingly from their 20s to their 60s (latex included), but also go head-to-head in intense scene after intense scene. Whether Nash is courting Alicia with a dazzling game of connect-the-dots using a galaxy of stars, or Alicia is racing to keep her mentally ill husband from harming their infant son, their relationship is played out with an uncommon urgency. It’s the kind of turn we’ve come to expect from last year’s Best Actor Oscar winner Crowe, 37, who again melds passion and intelligence to bring the horror of schizophrenia out of the shadows. The movie is also a bona fide career-catapulter for ”Requiem for a Dream” player Connelly, 31. As the never-quietly suffering wife of a genius, she finds a brilliance all her own.