Prof Vlatko Vedral FInstP

Abstract:

In this paper we argue that one-way quantum computation can be seen as a form of phase transition with the available information about the solution of the computation being the order parameter. We draw a number of striking analogies between standard thermodynamical quantities such as energy, temperature, work, and corresponding computational quantities such as the amount of entanglement, time, potential capacity for computation, respectively. Aside from being intuitively pleasing, this picture allows us to make novel conjectures, such as an estimate of the necessary critical time to finish a computation and a proposal of suitable architectures for universal one-way computation in 1D. © 2008 Springer Science+Business Media, LLC.

Abstract:

The Kolmogorov complexity of a string is the length of its shortest description. We define a second quantized Kolmogorov complexity where the length of a description is defined to be the average length of its superposition. We discuss this complexity's basic properties. We define the corresponding prefix complexity and show that the inequalities obeyed by this prefix complexity are also obeyed by von Neumann entropy. © 2008 World Scientific Publishing Company.

Abstract:

We consider the characterization of entanglement from the perspective of a Heisenberg formalism. We derive a two-party generalized separability criterion, and from this describe a physical understanding of entanglement. We find that entanglement may be considered as fundamentally a local effect, and therefore as a separate computational resource from nonlocality. We show how entanglement differs from correlation physically, and explore the implications of this concept of entanglement for the notion of classicality. We find that this understanding of entanglement extends naturally to multipartite cases. © 2007 The American Physical Society.