arXiv subjects

Tony Short

Publications and source records attributed to Tony Short.

3 recordsLinked to original sources

arXiv2020

Channels, measurements and post-selection in quantum thermodynamics

We analyse the benefit, in terms of extracting work, of having a single use of a quantum channel or measurement in quantum thermodynamics. This highlights a connection between unital and catalytic channels, and some subtleties concerning the conditional work cost of implementing a measurement given that a certain result was obtained. We also consider post-selected measurements, and show that any non-trivial post-selection leads to an unbounded work benefit.

quant-ph↗

arXiv2005

Entanglement swapping for generalized non-local correlations

We consider an analogue of entanglement-swapping for a set of black boxes with the most general non-local correlations consistent with relativity (including correlations which are stronger than any attainable in quantum theory). In an attempt to incorporate this phenomenon, we consider expanding the space of objects to include not only correlated boxes, but `couplers', which are an analogue for boxes of measurements with entangled eigenstates in quantum theory. Surprisingly, we find that no couplers exist for two binary-input/binary-output boxes, and hence that there is no analogue of entanglement-swapping for such boxes.

quant-ph↗

arXiv2005

The physics of no-bit-commitment : Generalized quantum non-locality versus oblivious transfer

We show here that the recent work of Wolf and Wullschleger (quant-ph/0502030) on oblivious transfer apparently opens the possibility that non-local correlations which are stronger than those in quantum mechanics could be used for bit-commitment. This is surprising, because it is the very existence of non-local correlations which in quantum mechanics prevents bit-commitment. We resolve this apparent paradox by stressing the difference between non-local correlations and oblivious transfer, based on the time-ordering of their inputs and outputs, which prevents bit-commitment.

quant-ph↗