2000/10/19 by Sergei Khlebnikov, S. Khlebnikov, Khlebnikov, S.
Physics and Astronomy · #FOS: Physical sciences #Magnetic properties of thin films #Physics of Superconductivity and Magnetism #Quantum Physics (quant-ph) #Quantum and electron transport phenomena #Superconductivity (cond-mat.supr-con) #cond-mat.supr-con #quant-ph
paper · pdf · doi:10.48550/arxiv.quant-ph/0010072
13 pages, revtex, 1 figure; corrected calculation for low frequencies
openalex publication_date 2000/10/19 · arxiv created 2000/12/28 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A superconducting ring has different sectors of states corresponding to different values of the trapped magnetic flux; this multitude of states can be used for quantum information storage. If a current supporting a nonzero flux is set up in the ring, fluctuations of electromagnetic field will be able to ``detect'' that current and thus cause a loss of quantum coherence. We estimate the decoherence exponent for a ring of a round type-II wire and find that it contains a macroscopic suppression factor (δ/ R1)2, where R1 is the radius of the wire, and δ is the London penetration depth. We present some encouraging numerical estimates based on this result.