2000/06/04 by Nikolay Prokof’ev, Nikolay Prokof'ev, Prokof'ev, Nikolay +3
Physics and Astronomy · #Atomic and Subatomic Physics Research #Condensed Matter (cond-mat) #FOS: Physical sciences #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #cond-mat
paper · pdf · doi:10.48550/arxiv.cond-mat/0006054
5 pages, LaTex, 3 figures, submitted to PRL in May, 2000
arxiv created 2000/06/04 · openalex publication_date 2000/06/04 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We consider a SQUID tunneling between 2 nearly degenerate flux states. Decoherence caused by paramagnetic and nuclear spins in the low-T limit is shown to be much stronger than that from electronic excitations. The decoherence time τϕ is determined by the linewidth Eo of spin bath states, which can be reduced by a correct choice of ring geometry and isotopic purification. Eo can be measured in either field sweep or microwave absorption experiments, allowing both a test of the theory and design control.