src/setups/decompositions/entangle.js

// Decompose the entangle gate.
import {Control} from '../../meta/control';
import {All} from '../../ops/metagates';
import {
  X, H, EntangleGate
} from '../../ops/gates';
import DecompositionRule from '../../cengines/replacer/decompositionrule';

const _decompose_entangle = (cmd) => {
  const qr = cmd.qubits[0]
  const eng = cmd.engine

  Control(eng, cmd.controlQubits, () => {
    H.or(qr[0])
    Control(eng, qr[0], () => new All(X).or(qr.slice(1)))
  })
}

export default [
  new DecompositionRule(EntangleGate, _decompose_entangle)
]