AMID CREPITANT FLAMES and crying gulls, Pablo Larraín’s Ema begins with the same musical device that opened his previous film, Jackie (2016): a glissando, that quivering freefall between two notes ferried by string, synth, or breath. The sound of surrender to momentum, the sliding frequencies of a swoon. Jackie’s blooming glissandi laid a shortcut to intrigue where there was otherwise little, but with composer Nicolás Jaar, Larraín has found a way to spin that sonic texture into the core of his new film. Ema is about many things—a couple’s failed adoption, the special vitriol reserved for