N. David Mermin

Learn More
The role of measurement in quantum computation is examined in the light of John Bell’s critique of the how the term “measurement” is used in quantum mechanics. I argue that within the field of quantum computer science the concept of measurement is precisely defined, unproblematic, amd forms the foundation of the entire subject. Here are some words which . .(More)
To celebrate the 60th birthday of Charles H. Bennett I (1) publicly announce my referee reports for the original dense coding and teleportation papers, (2) present a very economical solution to the BernsteinVazirani problem that does not even hint at interference between multiple universes, and (3) describe how I inadvertently reinvented the Copenhagen(More)
As a pedagogical illustration of the Fourier-space approach to the crystallography of quasiperiodic crystals, a simple derivation is given of the spacegroup classification scheme for hexagonal and trigonal quasiperiodic crystals of rank 4. The categories, which can be directly inferred from the Fourier-space forms of the hexagonal and trigonal space groups(More)
The traditional crystallographic symmetry elements of screw axes and glide planes are subdivided into those that are removable and those that are essential. A simple real-space criterion, depending only on Bravais class, determines which types can be present in any space group. This terminological refinement is useful in expressing the complementary(More)