# Quantum information and reality

Andreas Doering ( Oxford University Computing Laboratory )

- 16:30 19th January 2010 ( week 1, Hilary Term 2010 )Lecture Theartre B

Quantum Information Theory (QIT) is in large parts a practical
endeavour that utilises some of the counterintuitive features of
quantum systems to perform computational tasks faster than classical
systems can. But since some of the still mysterious aspects of quantum
theory are used, one is inevitably lead into questions on the
foundations of quantum theory, too. For example, there is no direct
access to quantum information: all one can do to extract information
from a quantum system is to perform a measurement on a qubit, the
alleged carrier of quantum information, to obtain a classical bit.
This points to the deeper problem that the usual mathematical
formalism of quantum theory does not provide a picture of reality, but
needs an interpretation in terms of measurements, classical observers
etc. After briefly reviewing some aspects of QIT from a conceptual
perspective, I will sketch a new mathematical formulation of quantum
theory that allows for a realist interpretation -- the topos approach.