Nathaniel David Mermin (/ˈmɜːrmɪn/; born 30 March 1935) is a solid-state physicist at Cornell University best known for the eponymous Hohenberg–Mermin–Wagner theorem, his application of the term "boojum" to superfluidity, his textbook with Neil Ashcroft on solid-state physics, and for contributions to the foundations of quantum mechanics and quantum information science.

[4] Mermin was the first to note how the three-particle GHZ state demonstrates that no local hidden-variable theory can explain quantum correlations,[5][6] and together with Asher Peres, he introduced the "magic square" proof, another demonstration that attempting to "complete" quantum mechanics with hidden variables does not work.

[8] In collaboration with Charles Bennett and Gilles Brassard, he made a significant early contribution to quantum cryptography.

[3] Inspired by Lewis Carroll's comic poem The Hunting of the Snark, Mermin introduced the term boojum into the vocabulary of condensed-matter physics.

[13] In his book It's About Time (2005), one of several expository pieces on special relativity, he suggests that the English foot (0.3048 meters) be slightly modified to approximately 29.98 cm.