Best Poster Award

SFB BeyondC encourages young researchers to present their results during poster sessions at the SFB events. Twice per year the “Best Poster Award” of 200 Euros will be granted.

On this page we have listed all the winners of the "Best Poster Award".

Macroscopicity of Matter Wave Interference

Björn Schrinski

Universität Duisburg-Essen
International Conference on Quantum Optics 2020

One driving force to motivate interference experiments involving high masses,long interference times, and large path separations is to verify the validity of theSchrödinger equation on ever larger scales. The degree of macroscopicity can beassessed by the amount of falsified modifications of quantum mechanics (collapsemodels [1]) which may be quantified with help of the underlying parameter space [2]. We focus on the fundamental measurement outcomes by applying Bayesianparameter estimation [3] and discuss state of the art experiments [4,5,6].

[1] Bassi et al., Rev. Mod. Phys. 85 (2013) [2] Nimmrichter et al., Phys. Rev.Lett. 110 (2013) [3] Schrinski et al., Phys. Rev. A 100 (2019) [4] Kovachy et al.,Nature 528 (2015) [5] Fein et al., Nat. Phys. (2019) [6] Xu et al., Science 366 (2019)

Quantum Computing with Graphene Plasmons

Irati Alonso Calafell, J. D. Cox, M. Radonjić, J. R. M. Saavedra, F. J. García de Abajo, L. A. Rozema, P. Walther University of Vienna

University of Vienna
Austrian Quantum Information Conference 2019

Among the various approaches to quantum computing, all-optical architectures are especially promising due to the robustness and mobility of single photons. However, the creation of the two-photon quantum logic gates required for universal quantum computing remains a challenge. Here we propose a universal two-qubit quantum logic gate, where qubits are encoded in surface plasmons in graphene nanostructures, that exploits graphene's strong third-order nonlinearity and long plasmon lifetimes to enable single-photon-level interactions. In particular, we utilize strong two-plasmon absorption in graphene nanoribbons, which can greatly exceed single-plasmon absorption to create a “square-root-of-swap” that is protected by the quantum Zeno effect against evolution into undesired failure modes. Our gate does not require any cryogenic or vacuum technology, has a footprint of a few hundred nanometers, and reaches fidelities and success rates well above the fault-tolerance threshold, suggesting that graphene plasmonics offers a route towards scalable quantum technologies.