More than 15 years after finishing his first string quartet, Arcadiana, Thomas Adès wrote a second one, The Four Quarters, which premiered in 2010. “All I’ve been able to discover over this time is that music only gets more and more mysterious,” the British composer said in his usual enigmatic way. In four movements, the work traces the passing of a day—from nightfall to dawn and daylight to the mystical “twenty-fifth hour.” The Danish String Quartet combines the piece with quartets by Joseph Haydn and Dmitri Shostakovich. The program concludes with the four musicians’ trade mark arrangements of Scandinavian folk music.