arXiv subjects

Marcin Pawłowski

Publications and source records attributed to Marcin Pawłowski.

41 records · Page 3Linked to original sources

arXiv2013

Robustness of quantum randomness expansion protocols in the presence of noise

In this paper we investigate properties of several randomness generation protocols in the device independent framework. Using Bell-type inequalities it is possible to certify that the numbers generated by an untrusted device are indeed random. We present a selection of certificates which guarantee two bits of randomness for each run of the experiment in the noiseless case and require the parties to share a maximally entangled state. To compare them we study their efficiency in the presence of white noise. We find that for different amounts of noise different operators are optimal for certifying most randomness. Therefore the vendor of the device should use different protocols depending on the amount of noise expected to occur. Another of our results that we find particularly interesting is that using a single Bell operator as a figure of merit is rarely optimal.

quant-ph↗

arXiv2013

Free randomness amplification using bipartite chain correlations

A direct analysis of the protocol of randomness amplification using Bell inequality violation is performed in terms of the convex combination of no-signaling boxes required to simulate quantum violation of the inequality. The probability distributions of bits generated by a Santha-Vazirani source are shown to be mixtures of permutations of Bernoulli distributions with parameter defined by the source. An intuitive proof is provided for the range of partial randomness from which perfect randomness can be extracted using quantum correlations violating the chain inequalities. Exact values are derived in the asymptotic limit of a large number of measurement settings.

quant-ph↗

arXiv2012

Semi-device independent random number expansion protocol with n to 1 quantum random access codes

We study random number expansion protocols based on the $n \to 1$ quantum random access codes (QRACs). We consider them in the semi-device independent scenario where the inner workings of the devices are unknown to us but we can certify the dimensions of the systems being communicated. This approach does not require the use of the entanglement and makes the physical realization of these protocols much easier than in the standard device independent scenario. In our work, we propose a protocol for randomness expansion, compute min-entropy for the semi-device independent protocol, and investigate $n\to 1$ QRACs with a view to their use in randomness expansion protocols. We also calculate the dependence of the effectiveness of the randomness generation on $n$ and find it optimal for $n=3$, and provide the explanation for this fact.

quant-ph↗

arXiv2011

Information Causality

We review the literature on Information Causality. Since it's for a book, we don't think an abstract will be needed at all, so we have written this one just for the sake of the arXiv.

quant-ph↗

arXiv2006

Superfast Algorithms and the Halting Problem in Geometric Algebra

A new type of algorithms is presented that combine the advantages of quantum and classical ones. Those combined advantages along with aspects of Geometric Algebra that open possibilities unavailable to both of these computations are exploited to obtain database search and number factoring algorithms that are faster than the quantum ones, and even to create a ''pseudoalgorithm'' that can perform noncomputational tasks.

quant-ph↗