APS March Meeting 2026, Day 2
Today was again a bit random, as I had talks for both one of my students and me, and meetings with folks. Some highlights: Edoardo Baldini ...
Large variations in the energy relaxation time (T1) of superconducting qubits make it difficult to accurately evaluate and compare new qubit materials and fabrication processes, or to perform studies that require precise measurements of energy loss. To address this issue, we present techniques for characterizing qubit quality factors by applying electric fields to TLS in the vicinity of qubits. Introducing low-frequency (<1 Hz) AC fields allows us to stabilize the measured T1 by averaging over the accessible TLS configurations, producing a robust estimate of T1 that is difficult to replicate with hundreds of measurements over long periods, without applied fields. In a complementary technique, we apply a randomly selected DC field to the qubit and measure T1. Repeated ‘fast-random’ measurements reveal a distribution of T1 values whose harmonic mean is consistent with that obtained through AC measurements but illustrates a wider range of qubit lifetimes induced by TLS interactions. We implement these TLS control techniques in various ways, including demonstrating a simple T1 improvement protocol and precise measurements of T1 vs temperature. These techniques will facilitate our understanding of how to improve qubit coherence by enabling better measurements in shorter times or with fewer devices.
Today was again a bit random, as I had talks for both one of my students and me, and meetings with folks. Some highlights: Edoardo Baldini ...