Noise in Quantum and Classical Computation and Non-locality
Falk Unger

Abstract:
Quantum computers seem to have capabilities which go beyond those of
classical computers. A particular example which is important for
cryptography is that quantum computers are able to factor numbers much
faster than what seems possible on classical machines.

In order to actually build quantum computers it is necessary to build
sufficiently accurate hardware, which is a big challenge.  In part 1
of this thesis we prove lower bounds on the accuracy of the hardware
needed to do quantum computation.  We also present a similar result
for classical computers.

One resource that quantum computers have but classical computers do
not have is entanglement. In Part 2 of this thesis we study certain
general aspects of entanglement in terms of quantum XOR games and
non-locality.