2001/01/30 by Jacek Dziarmaga, Dziarmaga, Jacek
Computer Science · Physics and Astronomy · #Condensed Matter (cond-mat) #FOS: Physical sciences #Quantum Computing Algorithms and Architecture #Quantum Physics (quant-ph) #Quantum and electron transport phenomena #Quantum many-body systems #cond-mat #quant-ph
paper · pdf · doi:10.48550/arxiv.cond-mat/0101454
4 pages in RevTex plus 2 .eps figures
arxiv created 2001/01/30 · openalex publication_date 2001/01/30 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A persistent current qubit has two quantum states with opposite currents flowing in a superconducting loop. Their magnetic field couple to nuclear spins. The qubit state is not only perturbed by the spins but it also gets entangled with the spins' state on a very short timescale. However, when the same spins are exposed to a strong but less than critical external magnetic field, then the qubit field is just a small perturbation on top of the external field and the entanglement with each spin is negligible. For a qubit which is more microscopic than certain threshold this partial entanglement results in negligible partial decoherence.