Quantum physics

Quantum physics revealed that particles changed their behaviour when observed. (AUDIO: ScrapeJane)

Quantum theory was one of the subjects 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)