ROM-based computation: quantum versus classical (pp324-332)
        B.C. Travaglione, M.A. Nielsen, H.M. Wiseman, and A. Ambainis
          doi: https://doi.org/10.26421/QIC2.4-5
Abstracts: We introduce a model of computation based on \emph{read only memory} (ROM), which allows us to compare the space-efficiency of reversible, error-free classical computation with reversible, error-free quantum computation. We show that a ROM-based quantum computer with one writable qubit is universal, whilst two writable bits are required for a universal classical ROM-based computer. We also comment on the time-efficiency advantages of quantum computation within this model.
Key words: quantum space complexity, read only memory, reversible computation