Spectral signatures of non-trivial topology in a superconducting circuit

• DOI: 10.48550/arxiv.2401.10876
• Publication Date: 2024-01-01
• Authors: L. Peyruchat; R. Rodriguez; Jean-Loup Smirr; Raphaël Leone; Çaǧlar Girit
• Keywords: Superconductivity (cond-mat.supr-con); Quantum Physics; Condensed Matter - Mesoscale and Nanoscale Physics; Physics; QC1-999; Condensed Matter - Superconductivity; Mesoscale and Nanoscale Physics (cond-mat.mes-hall); FOS: Physical sciences; Quantum Physics (quant-ph); [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall]

Topology, like symmetry, is a fundamental concept in understanding general properties of physical systems. In condensed matter systems, non-trivial topology may manifest itself as singular features the energy spectrum or quantization observable quantities such electrical conductance and magnetic flux. Using microwave spectroscopy, we show that superconducting circuit with three Josephson tunnel junctions parallel can possess degeneracies indicative $\textrm{\emph{intrinsic}}$ topology. We identify topological invariants, one which related to hidden quantum mechanical supersymmetry. Depending on fabrication parameters, devices are gapless not, fall simple phase diagram shown be robust perturbations including junction imperfections, asymmetry, inductance. circuits, readily fabricated conventional microlithography techniques, allow access wide range systems have no analog. Notable spectral these flat bands, leveraged for information applications, whereas quantized transport could useful metrology applications.