@@ -593,20 +593,18 @@ various themes: the relation between \zx and other quantum computing representat
Several powerful high-level languages (HLLs) have been proposed for quantum programs, such as Quipper~\cite{Alexander-S.-Green:2013fk} and \Qsharp~\cite{qsharp}.
As with classical HLLs, these languages are not designed to be run directly on quantum hardware: instead, their compilers typically output quantum circuit descriptions, which are not tailored well to run on any particular hardware platform.
Our proposed \dzxc system would represent an interface between multiple different HLLs for quantum procedures, and various quantum hardware platforms.
This system would use terms of the \zxcalculus as an internal representation of the procedure as it undergoes optimisations and translations to fit a particular hardware architecture.
Our proposed \dzxc system will represent an interface between multiple different HLLs for quantum procedures, and various quantum hardware platforms.
This system will use terms of the \zxcalculus as an internal representation of the procedure as it undergoes optimisations and translations, \newt{both abstractly and} to fit a particular hardware architecture.
This representation would not be required from or exposed to the user,\footnote{This said, the \zxcalculus has proved a very useful notation for mathematical proofs.}
but would be generated by a compiler front-end from programs written in existing high-level languages.
Therefore it is essential to provide a robust, general framework for compilation of HLLs to \zx terms.
As most existing quantum HLLs can output circuit descriptions, and as circuits can easily be represented in the \zxcalculus,
we first focus on a simple front end for the circuit language QASM~\cite{Cross2017Open-Quantum-As} in \ref{task:HHL} before moving towards more expressive HHLs.
As most existing quantum HLLs can output circuit descriptions, and as circuits can easily be represented in the \zxcalculus, \newt{in \ref{task:HHL}} we first focus on a simple front end for the circuit language QASM~\cite{Cross2017Open-Quantum-As} before moving towards more expressive HHLs.
This will allow virtually any extant quantum HLL to interface with the \dzxc system, albeit rather naively at first.
Later, we will perform concrete front-end
experiments using more sophisticated existing HLLs in, for example
\emph{Quipper}, \Qsharp~\cite{qsharp}, or ProjectQ
\cite{Steiger2016ProjectQ:-An-Op}, with the help of
Task~\ref{task:betterboxes}.
\cite{Steiger2016ProjectQ:-An-Op}, with the help of \newt{Task~\ref{task:trans1}}.
Proposed and existing quantum devices differ along a variety of axes.
At the most abstract level, the quantum circuit model and the
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@@ -623,7 +621,7 @@ modes.\REM{noise,fidelitY}
Due to the novelty of our proposal, we adopt an exploratory approach with respect to back-end models.
Initially, and in parallel, we study the circuit model (\ref{task:circuit-model}) and
the 1-way model (\ref{task:mbqc-model}) because these models are well understood, stable, and have been extensively treated in the \zxcalculus literature.
These models will allow us to prototype the development of hardware annotations for the \dzxc system.
These models will allow us to prototype the development of hardware annotations for the \dzxc system, \newt{cf.\ Task~\ref{task:runnable}}.
In both cases, this involves three tightly related tasks:
