Nathaniel David Mermin (/ˈmɜrmɪn/; born 1935) is a solid-state physicist at Cornell University best known for the eponymous Mermin–Wagner theorem, his application of the term "Boojum" to superfluidity, and for the quote "Shut up and calculate!"Together with Neil Ashcroft, Mermin has written an esteemed textbook, Solid State Physics. Mermin is a proponent of Quantum Bayesianism.