 
Summary: HighLevel Methods for Quantum Computation and Information
Samson Abramsky
Oxford University Computing Laboratory
1. Background
Quantum information and computation is concerned
with the use of quantummechanical systems to carry out
computational and informationprocessing tasks [18]. In
the few short years that this approach has been studied, a
number of remarkable concepts and results have emerged,
most notably:
A couple of spectacular algorithms  Shor's
polynomialtime algorithm for prime factorization
[23] and Grover's sublinear search algorithm [14].
A number of information protocols, exemplified by
quantum teleportation, which exploit quantum entan
glement in an essential fashion. We give a thumbnail
sketch of teleportation here, since it may be less famil
iar, and it will serve as a useful motivating example.
Teleportation uses just two classical bits to transport
an unknown qubit q from one site to another. Since a
