June 2023
Abstracts of the Quantum Center Lunch Seminar
Date: Thursday, June 1, 2023
Place: ETH Zurich, Hönggerberg, HPF G 6
Time: 12:00 - 13:30
On the path to a magnonic qubit
William Legrand - Magnetism and Interface Physics (Gambardella group), ETH Zurich
Magnetically ordered ensembles such as ferromagnets experience elementary excitations, quantized into magnons1. Their fundamental properties as well as their hybridization with light have been studied in the context of cavity quantum electrodynamics2-4. The recent progress in electron spin resonance spectroscopy based on nanofabricated superconducting resonators5,6, rather than bulk electromagnetic cavity resonators, offers a very relevant integrated approach to design hybrid quantum systems composed of nanoscale magnetically ordered ensembles7,8.
We investigate here some hybrid systems coupling superconducting resonators and high-quality, thin film ferrimagnetic insulators, such as yttrium iron garnet. Being able to bring the desirable magnetic properties of these epitaxially-grown crystals into experiments compatible with low temperatures requires some new approaches. We will present our results on yttrium iron garnet synthesis and their magnetic properties, new instrumentation that is relevant for this class of experiments, and conceptual progress with respect to enhancing inductive couplings between magnons and photons. This opens the perspective of realizing few-level magnon systems, suitable for the investigation of quantum states for the magnonic degree of freedom.
[1] Holstein, T. & Primakoff, H. Phys. Rev. 1940, 58, 1098-1113. [2] Tabuchi, Y. et al. Phys. Rev. Lett. 2014, 113, 083603. [3] Tabuchi, Y. et al. Science 2015, 349, 405-408. [4] Lachance-Quirion, D. et al. Science 2020, 367, 425-428. [5] Albertinale, E. et al. Nature 2021, 600, 434-438. [6] Wang, Z. et al. arXiv preprint 2023, arXiv:2301.02653. [7] Li, Y. et al. Phys. Rev. Lett. 2019, 123, 107701. [8] Hou, J. T. & Liu, L. Phys. Rev. Lett. 2019, 123, 107702.
Simulation of Gauge Theories: From classical limitations to quantum opportunities
Joao Pinto Barros - High Performance Computational Physics (Marinkovic group), ETH Zurich
Classical simulations of lattice gauge theories have been tremendously successful, in particular in the study of Quantum Chromodynamics (QCD). Notwithstanding, certain problems, such as real-time evolution, remain open and are not expected to be fully resolved within classical algorithms. Quantum simulations of gauge theories offer a promising avenue for answering open questions and exploring a vast landscape of characteristic physical phenomena. In this talk, we will explore the challenges, and phenomena, associated with classical and quantum simulation of lattice gauge theories, focusing on analog simulators with ultracold atoms.