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Q: Fachverband Quantenoptik und Photonik
Q 10: Quantum Information (Concepts and Methods) II
Q 10.4: Talk
Monday, March 14, 2022, 17:15–17:30, Q-H12
Bohmian Trajectories of Quantum Walks — •Florian Huber1,2,3, Carlotta Versmold1,2,3, Jan Dziewior1,2,3, Lukas Knips1,2,3, Harald Weinfurter1,2,3, and Jasmin Meinecke1,2,3 — 1Department für Physik, Ludwig-Maximilians-Universität, Munich, Germany — 2Max-Planck-Institut für Quantenoptik, Garching, Germany — 3Munich Center for Quantum Science and Technology (MCQST), Munich, Germany
Quantum walks are the quantum mechanical equivalent to the classical random walk and ,in standard quantum mechanics (QM), describes the coherent propagation of a quantum particle in a discrete environment, which cannot be represented with trajectories, as it would be possible in the classical case. However, certain interpretations of QM, as for example Bohmian mechanics, a non-local hidden variable theory, attribute definite positions and momenta to particles and therefore allow particle trajectories. In classical electrodynamics energy flow lines of photons, given by the Poynting vectors, correspond to these Bohmian trajectories. Here we report on the simulation and how to observe energy flow lines of a quantum walk, realized in an integrated waveguide array written into fused silica substrate. The curvature of the phase front, corresponding to the Poynting vector is reconstructed via weak measurements. To this end, the curvature is first weakly coupled to the polarization of the photons. Subsequently, a strong polarization measurement, behind a phase front preserving magnification optics, gives the desired information on the phase front curvature and thus makes a reconstruction of the Bohmian trajectories possible.