2001/02/14 by M. Dube, Marc A. Dubé, P. C. E. Stamp · 5 citations
Computer Science · Materials Science · Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Magnetism in coordination complexes #Nonlinear Dynamics and Pattern Formation #cond-mat.mes-hall #quant-ph
paper · pdf · doi:10.1016/s0301-0104(01)00303-2
Typos corrected, invited article to appear in special issue of Chemical Physics on "Quantum Physics of Open Systems"
arxiv created 2001/02/14 · openalex publication_date 2001/06/01 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We briefly review the oscillator and spin bath models of quantum environments, which can be used to describe the low-energy dynamics of open quantum systems. We then use them to discuss both the mechanisms causing decoherence at low T, and the dynamics of this decoherence. This is done first for a central 2-level system coupled to these environments- the results can be applied to the dynamics of quantum nanomagnets and superconducting SQUIDs, where large-scale tunneling of magnetisation and flux take place. Decoherence in these systems is caused principally by coupling to electrons and nuclear spins, the spin bath couplings are particularly dangerous at low T. These models are also generalised to discuss quantum measurements in which the measured system, the measuring apparatus, and the environment are treated quantum mechanically. The results can be used to calculate the dynamics of coupled SQUIDs and/or nanomagnets, in which one acts as a measuring apparatus and the other exhibits large-scale quantum superpositions. The same model can be used to describe coupled qubits.