  We present a theory of negative Coulomb drag in capacitively coupled quantum
wires based on the commensurability of the electron density and the long-range
nature of the Coulomb interaction in the Tomonaga-Luttinger liquid. The
commensurability introduces a notion of doped particles and holes. We point out
that the long-range interaction allows a particle-hole pairing over the wires
and that the particle-hole pairing brings about the positive drag of holes,
that is, the negative drag.
