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Please use this identifier to cite or link to this item: https://dspace.lboro.ac.uk/2134/27339

Title: Open quantum systems, effective Hamiltonians, and device characterization
Authors: Dwyer, Vincent M.
Duffus, Stephen N.A.
Everitt, Mark J.
Issue Date: 2017
Publisher: © American Physical Society
Citation: DWYER, V.M., DUFFUS, S.N.A. and EVERITT, M.J., 2017. Open quantum systems, effective Hamiltonians, and device characterization. Physical Review B: Condensed Matter and Materials Physics, 96, 134520
Abstract: High fidelity models, which are able to both support accurate device characterization and correctly account for environmental effects, are crucial to the engineering of scalable quantum technologies. As it ensures positivity of the density matrix, one preferred model of open systems describes the dynamics with a master equation in Lindblad form. In practice, Linblad operators are rarely derived from first principles, and often a particular form of annihilator is assumed. This results in dynamical models that miss those additional terms which must generally be added for the master equation to assume the Lindblad form, together with the other concomitant terms that must be assimilated into an effective Hamiltonian to produce the correct free evolution. In first principles derivations, such additional terms are often canceled (or countered), frequently in a somewhat ad hoc manner, leading to a number of competing models. Whilst the implications of this paper are quite general, to illustrate the point we focus here on an example anharmonic system; specifically that of a superconducting quantum interference device (SQUID) coupled to an Ohmic bath. The resulting master equation implies that the environment has a significant impact on the system’s energy; we discuss the prospect of keeping or canceling this impact and note that, for the SQUID, monitoring the magnetic susceptibility under control of the capacitive coupling strength and the externally applied flux results in experimentally measurable differences between a number of these models. In particular, one should be able to determine whether a squeezing term of the form ˆX ˆ P + ˆ P ˆX should be present in the effective Hamiltonian or not. If model generation is not performed correctly, device characterization will be prone to systemic errors.
Version: Published
DOI: 10.1103/PhysRevB.96.134520
URI: https://dspace.lboro.ac.uk/2134/27339
Publisher Link: https://doi.org/10.1103/PhysRevB.96.134520
ISSN: 2469-9950
Appears in Collections:Published Articles (Mechanical, Electrical and Manufacturing Engineering)
Published Articles (Physics)

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