Quantum parallelism efficiency conjecture

Consider a quantum parallel computation performed by a quantum parallel random-access machine, or QPRAM, and let its efficiency be the ratio of the serial work to the product of the parallel running time and the number of processors. Quantum parallelism efficiency conjecture. Unlike classical parallel computing, the efficiency of quantum parallel computing can be greater than $1$. The source motivates this claim through the Quantum Parallelism Thesis, but the supplied text does not establish it; elsewhere it explicitly describes this conjecture as open because the capabilities of quantum computers relative to conventional PRAMs remain unclear.