  The single-particle excitations of a superconductor are coherent
superpositions of electrons and holes near the Fermi level, called Bogoliubov
quasiparticles. They are Majorana fermions, meaning that pairs of
quasiparticles can annihilate. We calculate the annihilation probability at a
beam splitter for chiral quantum Hall edge states, obtaining a 1 +/- cos phi
dependence on the phase difference phi of the superconductors from which the
excitations originated (with the +/- sign distinguishing singlet and triplet
pairing). This provides for a nonlocal measurement of the superconducting phase
in the absence of any supercurrent.
