Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Are all reversible computations tidy?   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}.

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The categories of this paper are: cmp-lg
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The categories of this paper are: eess
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-lat
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The categories of this paper are: supr-con
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The categories of this paper are: hep-ph
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The categories of this paper are: nlin
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The categories of this paper are: bayes-an
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The categories of this paper are: funct-an
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The categories of this paper are: q-alg
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The categories of this paper are: q-bio
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The categories of this paper are: nucl-ex
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The categories of this paper are: math-ph
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The categories of this paper are: adap-org
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The categories of this paper are: dg-ga
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The categories of this paper are: chem-ph