Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 44: Optical Properties I

HL 44.11: Hauptvortrag

Mittwoch, 9. März 2016, 12:45–13:15, H10

From a loophole-free Bell test to a secure quantum Internet — •Ronald Hanson — QuTech and Kavli Institute of Nanoscience, Delft University of Technology, The Netherlands

For more than 80 years, the counterintuitive predictions of quantum theory have stimulated debate about the nature of reality. In his seminal works, John Bell showed that in any theory in which events only have local causes, the correlations between distant measurements satisfy an inequality and, moreover, that this inequality can be violated according to quantum theory. In the past decades, numerous ingenious Bell inequality tests have been reported. However, because of experimental limitations, all experiments to date required additional assumptions to obtain a contradiction with local realism, resulting in "loopholes".

In this talk I will explain our recent Bell experiment that is free of any such additional assumption [1], in which we entangle two electron spins in diamond separated by more than 1 km. I will discuss the implications of its result for possible models of nature. Furthermore, I will speculate how this result, combined with recently achieved control over individual nuclear spins in diamond [2] and teleportation between separated diamond chips [3], may lead to a quantum Internet secured through device-independent protocols - reaching the ultimate physical limits of privacy [4].

[1] B. Hensen et al., Nature 526, 682 (2015). [2] J. Cramer et al., arXiv:1508.01388 (2015). [3] W. Pfaff et al., Science 345, 532 (2014). [4] A. Ekert and R. Renner, Nature 507, 443 (2014).