Bloch Waves and Fuzzy Cylinders: 1/4-BPS Solutions of Matrix Theory
  In this note, we present a broad class of quarter-BPS solutions to matrix theory, corresponding to non-commutative cylinders of arbitrary cross-sectional profile in R^8. The solutions provide a microscopic description of a general supertube configuration. Taking advantage of an analogy between a compact matrix dimension and the Hamiltonian of a 1-dimensional crystal, we use a Bloch wave basis to diagonalize the transverse matrices, finding a distribution of eigenvalues which smoothly trace the profile curve as the Bloch wave number is varied. 
Peter G. Shepard (UC Berkeley)