Apparatus and methods for performing quantum computations are disclosed.
Such apparatus and methods may include identifying a first quantum state
of a lattice having a system of quasi-particles disposed thereon, moving
the quasi-particles within the lattice according to at least one
predefined rule, identifying a second quantum state of the lattice after
the quasi-particles have been moved, and determining a computational
result based on the second quantum state of the lattice. A topological
quantum computer encodes information in the configurations of different
braids. The computer physically weaves braids in the 2D+1 space-time of
the lattice, and uses this braiding to carry out calculations. A pair of
quasi-particles, such as non-abelian anyons, can be moved around each
other in a braid-like path. The quasi-particles can be moved as a result
of a magnetic or optical field being applied to them, for example. When
the pair of quasi-particles are brought together, they may annihilate
each other or create a new anyon. A result is that an anyon may be
present or not, which can be thought of as a "one" or "zero,"
respectively. Such ones and zeros can be interpreted to provide
information.