quchip.chip.transformations.eliminate_effective¶
Diagonalize selected effective terms through a captured change of coordinates.
Every device and edge survives with its authored parameters. An exact rotation diagonalizes the selected terms together with the local Hamiltonians of the devices they act on. The kept matrix holds the resulting level-dependent shifts and the effect of the rotation on every other interaction in the chip.
Functions
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Diagonalize one effective contribution exactly and keep its complete correction. |
- quchip.chip.transformations.eliminate_effective.reduce_effective_terms(chip, target, method)[source]¶
Diagonalize one effective contribution exactly and keep its complete correction.
The rotation uses only the selected terms and the isolated local Hamiltonians of the devices they act on. Dressed states take the bare label of largest overlap. Its action on the full chip, including couplings and other effective terms, is kept, so dressed queries on the reduced chip return the source spectrum at the chip’s approximation. Only
method='exact'is implemented, because a second-order expansion is not reliable for a strong nonlinearity such as a junction cosine. Exact derivatives require a locally stable dressed assignment and nondegenerate eigenpairs.