Physics – Quantum Physics
Scientific paper
2004-03-10
Physics
Quantum Physics
7 pages, 1 figure eps
Scientific paper
It has long been known that to minimise the heat emitted by a deterministic computer during it's operation it is necessary to make the computation act in a logically reversible manner\cite{Lan61}. Such logically reversible operations require a number of auxiliary bits to be stored, maintaining a history of the computation, and which allows the initial state to be reconstructed by running the computation in reverse. These auxiliary bits are wasteful of resources and may require a dissipation of energy for them to be reused. A simple procedure due to Bennett\cite{Ben73} allows these auxiliary bits to be "tidied", without dissipating energy, on a classical computer. All reversible classical computations can be made tidy in this way. However, this procedure depends upon a classical operation ("cloning") that cannot be generalised to quantum computers\cite{WZ82}. Quantum computations must be logically reversible, and therefore produce auxiliary qbits during their operation. We show that there are classes of quantum computation for which Bennett's procedure cannot be implemented. For some of these computations there may exist another method for which the computation may be "tidied". However, we also show there are quantum computations for which there is no possible method for tidying the auxiliary qbits. Not all reversible quantum computations can be made "tidy". This represents a fundamental additional energy burden to quantum computations. This paper extends results in \cite{Mar01}.
No associations
LandOfFree
Are all reversible computations tidy? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Are all reversible computations tidy?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Are all reversible computations tidy? will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-418795