Upcoming Colloquia

COBRA COLLOQUIUM: Friday June 3, 2016 at 15:30 – 16:30 in Film Theater De Zwarte Doos.

Speaker: Prof.dr. Ronald Hanson, Antoni van Leeuwenhoek Professor at Delft University of
Technology and Roadmap Leader in the recently established institute QuTech.

Title: From a loophole-free Bell test to a quantum Internet

Abstract: 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 proved that no theory
of nature that obeys locality and realism could reproduce all the predictions of quantum theory. The resulting Bell inequality provided a recipe for experimental tests of the fundamental
principles underlying the laws of nature. In the past decades, numerous ingenious Bell inequality tests have been reported; however, because of experimental limitations, all required additional
assumptions to obtain a contradiction with local realism, resulting in “loopholes”.

I will discuss our recent experiment providing the first loophole-free Bell inequality violation [1]. We employ an event-ready scheme that generates entanglement between diamond electron spins
separated by more than 1 km. Furthermore, I will sketch how the techniques developed here, combined with recently achieved full control over individual nuclear spins [2] and teleportation
between separated devices [3] may enable the realization of a network of quantum bit registers for quantum computation and communication. In the long run, such networks 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., Nature Communications (in press); see arXiv:1508.01388.
[3] W. Pfaff et al., Science 345, 532 (2014).
[4] A. Ekert and R. Renner, Nature 507, 443 (2014).

Biography: Ronald Hanson (1976) is Antoni van Leeuwenhoek Professor at Delft University of Technology and Roadmap Leader in the recently established institute QuTech.
Hanson’s work in experimental quantum physics pursues state-of-the-art control of coupled quantum systems. His research aims for insights into fundamental concepts in quantum science as well as for realizing proof-of-principle quantum information technologies. Hanson is recipient of the QIPC Young Investigator Award (2012), the Nicholas Kurti European Science prize (2012) and the Royal Dutch Academy of Science - Ammodo prize for fundamental research (2015). He was elected member of the Young Academy of the Royal Dutch Academy of Sciences in 2010. Both His recent Bell experiment was chosen in the Top 10 scientific breakthroughs of the year by both Science and Nature.

After the colloquium (around 16:30) we organize a mini-colloquium in which two COBRA researchers, will give a short presentation about his or her work.

For the Electro-Optical Communications Group:
Speaker: Simone Cardarelli
Title: On chip electronic control of the optical beam profile

For the Physics of Nanostructures Group:
Speaker: Arno van den Brink
Title: A new direction for magnetic memory

The audience is invited to an informal gathering following the colloquium (around 17:00) in the lounge of Film Theater De Zwarte Doos.