Similar to TreeBQP except that the quantum computer's state at each time step is restricted to being exponentially close to a state in AmpP (that is, a state for which the amplitudes are computable by a classical polynomial-size circuit).
Defined in [Aar03b], where it was also observed that AmpP-BQP is contained in the third level of PH, just as TreeBQP is.
No class.