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class XXDecomposer(euler_basis='U', embodiments=None, backup_optimizer=None)

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Bases: object

A class for optimal decomposition of 2-qubit unitaries into 2-qubit basis gates of XX type (i.e., each locally equivalent to CAN(alpha, 0, 0) for a possibly varying alpha).


  • euler_basis (str) – Basis string provided to OneQubitEulerDecomposer for 1Q synthesis. Defaults to “U”.
  • embodiments (Optional[dict]) – A dictionary mapping interaction strengths alpha to native circuits which embody the gate CAN(alpha, 0, 0). Strengths are taken so that pi/2 represents the class of a full CX.
  • backup_optimizer (Optional[Callable]) – If supplied, defers synthesis to this callable when XXDecomposer has no efficient decomposition of its own. Useful for special cases involving 2 or 3 applications of XX(pi/2), in which case standard synthesis methods provide lower 1Q gate count.

If embodiments is not passed, or if an entry is missing, it will be populated as needed using the method _default_embodiment.




Counts the number of gates that would be emitted during re-synthesis.

NOTE: Used by ConsolidateBlocks.

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