Constant-depth quantum circuits with unbounded-fanout gates.
Defined in [Spa02].
Contains QNC0, and is contained in QACC0.Is equivalent to QACf0 due to [Tak12].
Same as QAC0, except that an additional "quantum fanout" gate is available, which CNOT's a qubit into arbitrarily many target qubits in a single step.
Defined in [Moo99], where it was also shown that QACf0 =QAC0[2] = QACC0.Is equivalent to QNCf0 due to [Tak12].
Constant-depth quantum circuits without fanout gates.
Defined in [Spa02].
Contained in QNCf0.