Vision of a quantum internet — 2018
A quantum internet may very well be the first quantum information technology to become reality. We published a comprehensive guide towards this goal in Science. It describes six phases, starting with simple networks of qubits that could already enable secure quantum communications – a phase that could be reality in the near future. The development ends with networks of fully quantum-connected quantum computers. In each phase, new applications become available such as extremely accurate clock synchronization or integrating different telescopes on Earth in one virtual ‘supertelescope’. This work creates a common language that unites the highly interdisciplinary field of quantum networking towards achieving the dream of a world-wide quantum internet.
Testing quantum repeaters and memories — 2018
Quantum bits are highly delicate and must be protected against noise and imperfections to realize a large scale quantum internet and a quantum computer. Our team has now devised a novel method with which the quality of quantum memories, error correction schemes and quantum repeaters to store and send quantum bits can be certified. The quality of these operations on quantum information is captured by its so-called quantum capacity.
In this work, we propose the first method to directly estimate this capacity for storing quantum information, even if the noise is arbitrarily correlated. The estimation protocol only needs single qubit operations and measurements, and does not require a quantum error correction scheme to be implemented in order to test the quantum memory.
In 1935, Einstein asked a profound question about our understanding of Nature: are objects only influenced by their nearby environment? Or could, as predicted by quantum theory, looking at one object sometimes instantaneously affect another far-away object? We tried to answer that question, by performing a loophole-free Bell test.
Loophole-free Bell inequality violation using electron spins separated by 1.3 kilometres
Bas Hensen, H. Bernien, A. E. Dréau, A. Reiserer, N. Kalb, M. S. Blok, J. Ruitenberg, R. F. L. Vermeulen, R. N. Schouten, C. Abellán, W. Amaya, V. Pruneri, Morgan W. Mitchell, M. Markham, D. J. Twitchen, D. Elkouss, S. Wehner, T. H. Taminiau, R. Hanson
Nature 526 (7575), 682-686 (2015)
online – arXiv – pdf