Adaptive Quantum Computation, Constant Depth Quantum Circuits and Arthur-Merlin Games (pp134-145) 
        Barbara M. Terhal and David P. DiVincenzo
          doi: https://doi.org/10.26421/QIC4.2-5
Abstracts: We present evidence that there exist quantum computations that can be carried out in constant depth, using 2-qubit gates, that cannot be simulated classically with high accuracy. We prove that if one can simulate these circuits classically efficiently then ${\rm BQP} \subseteq {\rm AM}$.
Key words: constant depath quantum circuits, quantum computation by teleportation