  We show that carbon nanotubes (CNT) are good candidates for realizing
one-dimensional topological superconductivity with Majorana fermions localized
near the end points. The physics behind topological superconductivity in CNT is
novel and is mediated by a recently reported curvature-induced spin-orbit
coupling which itself has a topological origin. In addition to the spin-orbit
coupling, an important new requirement for a robust topological state is broken
chirality symmetry about the nanotube axis. We use topological arguments to
show that, for recently realized strengths of spin-orbit coupling and broken
chirality symmetry, a robust topological gap of around 500 mK is achievable in
carbon nanotubes.
