2003/08/31 by M. I. Dykman, Lea F. Santos, L. F. Santos
Computer Science · Physics and Astronomy · #Quantum Information and Cryptography #Quantum and electron transport phenomena #Quantum many-body systems #cond-mat
paper · pdf · doi:10.1088/0305-4470/36/44/l01
published as J. Phys. A 36, L561 (2003) · Updated version
openalex publication_date 2003/10/22 · arxiv created 2003/11/13 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/30
We study a spin chain with an anisotropic XXZ coupling in a magnetic field. Such a chain models several proposed types of quantum computers. The chain contains a defect with a different on-site energy. The interaction between excitations leads to the onset of two-excitation states localized next to the defect. In a resonant situation scattering of excitations on each other might cause decay of an excitation localized on the defect. We find that destructive many-particle quantum interference eliminates this decay. Numerical results confirm the analytical predictions.