concise. This summary will be used to select suited reviewers for
the proposal.}
Recent investment in quantum technologies has paid off, and quantum computers are now here. Current and near-term quantum computers, known as noisy intermediate-scale quantum (NISQ) devices, have few qubits, short coherence times, and non-trivial gate error. In this regime, quantum software support -- in particular focussed towards compilation and optimisation -- is vital to the efficient use of scarce, noisy, hardware resources, and the development of implementable protocols that go beyond what is feasible classically.
These NISQ computers are not so much single devices, but instead patchworks of components (including classical) which vary greatly between implementations such as silicon qubits, superconducting circuits, or ion traps. Programming such devices currently requires intimate knowledge of the hardware, which is a significant barrier to the realisation of usable, scalable quantum computers, as programs must be rewritten for every new device. High-level software descriptions of quantum algorithms must be translated to low-level control instructions for quantum hardware.
\newt{Furthermore, whereas}
classical computers have had a roughly static concept of ``low-level instructions'' for decades, the analogous notion for quantum hardware is constantly changing and evolving to cope with the rapid progress in quantum technology. We face a situation where the ever-multiplying range of quantum computers has minimal software support.
We propose the development of ``deep quantum compilation'' technology, which is the concept of a compiler for quantum systems which can be used to develop large portions of the software stack, in a way which is modular in design but tightly integrated once compiled.
A ``deep'' quantum compiler will be versatile enough to target a wide variety of hardware implementations, and simple enough to support any programming language.
To develop such a compiler, we will leverage the versatility and the power of the \zxcalculus, a tensor-based system for analysing quantum operations.
Recent formal and practical advances in completeness and optimisation of the \zxcalculus demonstrate a proof-of-principle of the possibility of developing a deep quantum compiler, including provably-correct program transformations for automatically adding error correction and performing hardware-guided optimisations.
Developing such a compiler will allow for the sound development of tightly integrated software stacks for quantum computers, enabling them to perform computations better and faster.
We propose the development of ``deep quantum compilation'' technology, which is the concept of a compiler for quantum systems which can be used to develop large portions of the software stack, in a way which is modular in design but tightly integrated once compiled.
We propose to develop deep quantum compilation technology by leveraging the \zxcalculus, a versatile formal tool to efficiently reason about tensors, which recently demonstrated state-of-the-art capability to optimise unitary circuits.
This provides us with the opportunity to develop compiler technology with a scope that would be difficult to achieve otherwise.
Recent investment in quantum technologies has brought us into the era of noisy intermediate-scale quantum (NISQ) devices.
These computers are not so much single devices, but instead patchworks of components (including classical) which vary greatly between implementations such as silicon qubits, superconducting circuits, or ion traps.
Even as the technology matures, we may expect that even fault-tolerant quantum computers will be accompanied by a myriad of control systems, and a scarcity of resources.
Programming such devices currently requires intimate knowledge of the hardware.
This is a barrier to the realisation of quantum software, as programs must be rewritten for every new device to closely match the hardware model.
Furthermore, whereas classical computers have had a roughly static concept of ``low-level instructions'' for decades, the analogous notion for quantum hardware is constantly changing and evolving to cope with the rapid progress in quantum technology. We face a situation where the ever-multiplying range of quantum computers has minimal software support.
Solving this problem requires a ``deep'' quantum compiler --- one which can transform algorithms to match the resources and capabilities of diverse hardware platforms.
To develop such a compiler, we will leverage the versatility and the power of the \zxcalculus.
Recent formal and practical advances in completeness and optimisation of the \zxcalculus demonstrate a proof-of-principle of the possibility of developing a deep quantum compiler, including provably-correct program transformations for automatically adding error correction and performing hardware-guided optimisations.
Developing such a compiler will allow for the sound development of tightly integrated software stacks for quantum computers, enabling them to perform computations better and faster.
%The goal of this project is to develop the flexible intermediate for compilation and optimisation, which is necessary for the immediate-term practical implementation of post-classical protocols on noisy intermediate-scale quantum computers. %how many buzzwords can we get in this sentence
