2 Search Results for "Acín, Antonio"


Document
A Single Entangled System Is an Unbounded Source of Nonlocal Correlations and of Certified Random Numbers

Authors: Florian J. Curchod, Markus Johansson, Remigiusz Augusiak, Matty J. Hoban, Peter Wittek, and Antonio Acín

Published in: LIPIcs, Volume 73, 12th Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC 2017)


Abstract
The outcomes of local measurements made on entangled systems can be certified to be random provided that the generated statistics violate a Bell inequality. This way of producing randomness relies only on a minimal set of assumptions because it is independent of the internal functioning of the devices generating the random outcomes. In this context it is crucial to understand both qualitatively and quantitatively how the three fundamental quantities – entanglement, non-locality and randomness – relate to each other. To explore these relationships, we consider the case where repeated (non projective) measurements are made on the physical systems, each measurement being made on the post-measurement state of the previous measurement. In this work, we focus on the following questions: Given a single entangled system, how many nonlocal correlations in a sequence can we obtain? And from this single entangled system, how many certified random numbers is it possible to generate? In the standard scenario with a single measurement in the sequence, it is possible to generate non-local correlations between two distant observers only and the amount of random numbers is very limited. Here we show that we can overcome these limitations and obtain any amount of certified random numbers from a single entangled pair of qubit in a pure state by making sequences of measurements on it. Moreover, the state can be arbitrarily weakly entangled. In addition, this certification is achieved by near-maximal violation of a particular Bell inequality for each measurement in the sequence. We also present numerical results giving insight on the resistance to imperfections and on the importance of the strength of the measurements in our scheme.

Cite as

Florian J. Curchod, Markus Johansson, Remigiusz Augusiak, Matty J. Hoban, Peter Wittek, and Antonio Acín. A Single Entangled System Is an Unbounded Source of Nonlocal Correlations and of Certified Random Numbers. In 12th Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC 2017). Leibniz International Proceedings in Informatics (LIPIcs), Volume 73, pp. 1:1-1:23, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2018)


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@InProceedings{curchod_et_al:LIPIcs.TQC.2017.1,
  author =	{Curchod, Florian J. and Johansson, Markus and Augusiak, Remigiusz and Hoban, Matty J. and Wittek, Peter and Ac{\'\i}n, Antonio},
  title =	{{A Single Entangled System Is an Unbounded Source of Nonlocal Correlations and of Certified Random Numbers}},
  booktitle =	{12th Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC 2017)},
  pages =	{1:1--1:23},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-034-7},
  ISSN =	{1868-8969},
  year =	{2018},
  volume =	{73},
  editor =	{Wilde, Mark M.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.TQC.2017.1},
  URN =		{urn:nbn:de:0030-drops-85809},
  doi =		{10.4230/LIPIcs.TQC.2017.1},
  annote =	{Keywords: Randomness certification, Nonlocality, Entanglement, Sequences of measurements}
}
Document
Certifying the Absence of Apparent Randomness under Minimal Assumptions

Authors: Gonzalo de la Torre, Chirag Dhara, and Antonio Acin

Published in: LIPIcs, Volume 22, 8th Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC 2013)


Abstract
Contrary to classical physics, the predictions of quantum theory for measurement outcomes are of a probabilistic nature. Questions about the completeness of such predictions lie at the core of quantum physics and can be traced back to the foundations of the field. Recently, the completeness of quantum probabilistic predictions could be established based on the assumption of freedom of choice. Here we ask when can events be established to be as unpredictable as we observe them to be relying only on minimal assumptions, ie. distrusting even the free choice assumption but assuming the existence of an arbitrarily weak (but non-zero) source of randomness. We answer the latter by identifying a sufficient condition weaker than the monogamy of correlations which allow us to provide a family of finite scenarios based on GHZ paradoxes where quantum probabilistic predictions are as accurate as they can possibly be. Our results can be used for a protocol of full randomness amplification, without the need of privacy amplification, in which the final bit approaches a perfect random bit exponentially fast on the number of parties.

Cite as

Gonzalo de la Torre, Chirag Dhara, and Antonio Acin. Certifying the Absence of Apparent Randomness under Minimal Assumptions. In 8th Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC 2013). Leibniz International Proceedings in Informatics (LIPIcs), Volume 22, pp. 207-219, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2013)


Copy BibTex To Clipboard

@InProceedings{delatorre_et_al:LIPIcs.TQC.2013.207,
  author =	{de la Torre, Gonzalo and Dhara, Chirag and Acin, Antonio},
  title =	{{Certifying the Absence of Apparent Randomness under Minimal Assumptions}},
  booktitle =	{8th Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC 2013)},
  pages =	{207--219},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-55-2},
  ISSN =	{1868-8969},
  year =	{2013},
  volume =	{22},
  editor =	{Severini, Simone and Brandao, Fernando},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.TQC.2013.207},
  URN =		{urn:nbn:de:0030-drops-43112},
  doi =		{10.4230/LIPIcs.TQC.2013.207},
  annote =	{Keywords: randomness, Bell nonlocality, free choice}
}
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