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- Marco Tomamichel, Roger Colbeck, Renato Renner
- IEEE Transactions on Information Theory
- 2010

In classical and quantum information theory, operational quantities such as the amount of randomness that can be extracted from a given source or the amount of space needed to store given data are normally characterized by one of two entropy measures, called smooth min-entropy and smooth max-entropy, respectively. While both entropies are equal to the von… (More)

- Marco Tomamichel, Roger Colbeck, Renato Renner
- IEEE Transactions on Information Theory
- 2009

The classical asymptotic equipartition property is the statement that, in the limit of a large number of identical repetitions of a random experiment, the output sequence is virtually certain to come from the typical set, each member of which is almost equally likely. In this paper, a fully quantum generalization of this property is shown, where both the… (More)

- Ligong Wang, Renato Renner, Roger Colbeck
- 2009 IEEE International Symposium on Information…
- 2009

New channel coding converse and achievability bounds are derived for a single use of an arbitrary channel. Both bounds are expressed using a quantity called the “smooth 0-divergence”, which is a generalization of Rényi's divergence of order 0. The bounds are also studied in the limit of large block-lengths. In particular, they combine… (More)

- Roger Colbeck, Renato Renner
- Nature communications
- 2011

According to quantum theory, measurements generate random outcomes, in stark contrast with classical mechanics. This raises the question of whether there could exist an extension of the theory that removes this indeterminism, as suspected by Einstein, Podolsky and Rosen. Although this has been shown to be impossible, existing results do not imply that the… (More)

- Jonathan Barrett, Roger Colbeck, Adrian Kent
- ArXiv
- 2012

Outline • Motivation for device-independence • Brief History • Recent developments • Main result • Remaining problems and open questions Theoretical Start with 'clean', well-defined assumptions and try to prove security based on these. Two sides of cryptography Practical Try to build devices that satisfy the theoretical assumptions as closely as possible.… (More)

- Patrick J Coles, Roger Colbeck, Li Yu, Michael Zwolak
- Physical review letters
- 2012

Uncertainty relations provide constraints on how well the outcomes of incompatible measurements can be predicted, and as well as being fundamental to our understanding of quantum theory, they have practical applications such as for cryptography and witnessing entanglement. Here we shed new light on the entropic form of these relations, showing that they… (More)

- Roger Colbeck, Renato Renner
- Physical review letters
- 2012

Although quantum mechanics is one of our most successful physical theories, there has been a long-standing debate about the interpretation of the wave function--the central object of the theory. Two prominent views are that (i) it corresponds to an element of reality, i.e., an objective attribute that exists before measurement, and (ii) it is a subjective… (More)

- Roger Colbeck
- ArXiv
- 2007

We present attacks that show that unconditionally secure two-party classical computation is impossible for many classes of function. Our analysis applies to both quantum and relativistic protocols. We illustrate our results by showing the impossibility of oblivious transfer.

- Roger Colbeck, Adrian Kent
- ArXiv
- 2005

Alice is a charismatic quantum cryptographer who believes her parties are unmissable; Bob is a 1 glamorous string theorist who believes he is an indispensable guest. To prevent possibly traumatic collisions of self-perception and reality, their social code requires that decisions about invitation or acceptance be made via a cryptographically secure variable… (More)

T owards the end of 2011, Pusey, Barrett and Rudolph derived a theorem that aimed to show that the quantum state must be ontic (a state of reality) in a broad class of realist approaches to quantum theory. This result attracted a lot of attention and controversy. The aim of this review article is to review the background to the Pusey–Barrett– Rudolph… (More)