Dartmouth Events

Abstract: Nanomagnetic systems that exhibit clock transitions (CTs) have potential as qubits due to the suppression of the decohering effects of magnetic fluctuations to first order at the CTs, yielding substantially enhanced coherence times T2. The spin states that generate these CTs are addressable via electron-spin resonance (ESR) techniques. Similar to a spin-1 nanomagnet with a zero-field CT, silica (SiO2)-based glasses containing certain defects exhibit similar zero-field CT effects. In particular, borosilicate and aluminosilicate glasses demonstrate coherence times up to 5 µs at the CT; use of dynamical decoupling pulse sequences yield coherence times above 25 µs. We present characterization of these CTs using ESR in S-band in several different silica glass samples. The materials origin of these CTs is investigated via comparison to related materials, including boron and aluminum oxides, fused silica, and glasses in which impurities are primarily interstitial. Since boron and aluminum are acceptors when substituted for silicon, we suggest that the observed CT behavior is due to a spin-1 boron-vacancy center within borosilicate glass and, similarly, an aluminum-vacancy center in aluminosilicate glass.

Hosted by Professor Chandrasekhar Ramanathan

Zoom link: https://dartmouth.zoom.us/s/91597901421