aiqbench analysis
This research advances quantum control theory by demonstrating that concatenated composite pulses can maintain robustness against systematic errors even when local residual-error preservation is violated, provided global error cancellation occurs across the sequence. The study derives necessary and sufficient conditions for this behavior using first-order error generators, specifically addressing pulse-length and off-resonance errors common in magnetic resonance systems. By extending design principles beyond strict local constraints, the work offers new pathways for optimizing gate fidelity in quantum hardware without relying on idealized error preservation at every step.
Concatenated Composite Pulses Beyond Local Residual-Error Preservation
arXiv:2609.22728v1 Announce Type: new Abstract: Residual-error preservation (REP) provides a sufficient rule for constructing concatenated composite pulses that compensate multiple systematic errors. We show that local REP is not necessary: deviations from REP can cancel across the full sequence. Using first-order error generators, we derive a necessary and sufficient condition for concatenation to retain the robustness of an outer sequence. A simple sufficient condition is that all inner pulses rescale the corresponding elementary error generators by a common real factor, not necessarily unity. We illustrate this principle using pulse-length and off-resonance errors, two systematic error models commonly considered in magnetic resonance. Short CORPSE and SCROFULOUS each compensate one error without preserving the other locally. Combining these inner pulses with suitable equal-rotation-angle outer sequences yields simultaneous first-order compensation of both errors, extending concatenated composite-pulse design beyond local REP.
Abstract:Residual-error preservation (REP) provides a sufficient rule for constructing concatenated composite pulses that compensate multiple systematic errors. We show that local REP is not necessary: deviations from REP can cancel across the full sequence. Using first-order error generators, we derive a necessary and sufficient condition for concatenation to retain the robustness of an outer sequence. A simple sufficient condition is that all inner pulses rescale the corresponding elementary error generators by a common real factor, not necessarily unity. We illustrate this principle using pulse-length and off-resonance errors, two systematic error models commonly considered in magnetic resonance. Short CORPSE and SCROFULOUS each compensate one error without preserving the other locally. Combining these inner pulses with suitable equal-rotation-angle outer sequences yields simultaneous first-order compensation of both errors, extending concatenated composite-pulse design beyond local REP.
arXiv:2609.22728 [quant-ph]
(or arXiv:2609.22728v1 [quant-ph] for this version)
https://doi.org/10.48550/arXiv.2609.22728 Focus to learn more arXiv-issued DOI via DataCite (pending registration)
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Full text under the publisher's open licence · 223 words
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