Quantum physics
From Tardis Wiki, the free Doctor Who reference
Quantum physics was a subject studied by Susan before she and the First Doctor settled at Totter's Lane. (PROSE: Losing the Audience)
While waiting for Clara Oswald to finish her day of work at Coal Hill School, (PROSE: The Day of the Doctor) the Eleventh Doctor read a book on Advanced Quantum Mechanics, (TV: The Day of the Doctor) which bored him after he failed to find Wally anywhere and had to resort to reading the text. (PROSE: The Day of the Doctor)
