Quantum programming

Quantum programming is the process of designing or assembling sequences of instructions, called quantum circuits, using gates, switches, and operators to manipulate a quantum system for a desired outcome or results of a given experiment. Quantum circuit algorithms can be implemented on integrated circuits, conducted with instrumentation, or written in a programming language for use with a quantum computer or a quantum processor. With quantum processor based systems, quantum programming languages help express quantum algorithms using high-level constructs. The field is deeply rooted in the open-source philosophy and as a result most of the quantum software discussed in this article is freely available as open-source software. Quantum computers, such as those based on the KLM protocol, a linear optical quantum computing (LOQC) model, use quantum algorithms (circuits) implemented with electronics, integrated circuits, instrumentation, sensors, and/or by other physical means. Other ci

Practical Compilation of Quantum Programs

Bruno Schmitt Antunes

It's been a little more than 40 years since researchers first suggested exploiting quantum physics to build more powerful computers. During this time, we have seen the development of many quantum algorithms and significant technological advances to make these devices. As a result, at this point, large-scale quantum computers, capable of providing valuable solutions to complex problems, seem like a certainty, even if still distant.Nonetheless, there is a great gap between the communities of quantum algorithms and quantum devices researchers. On the one hand, algorithm designers most often describe algorithms in a high level of abstraction, using a mixture of natural language, pseudocode, and mathematical formulas---a form deriving asymptotic complexity estimates while shielding researchers from the low-level complexities and restrictions. On the other hand, physical devices only understand algorithms implemented using the primitive low-level abstractions they support.Most programming systems available for quantum computing are intertwined with the quantum circuit model, so developers must implement algorithms in terms of low-level unitary operators. Not surprisingly, the implementation of quantum algorithms on such a low level of abstraction is very time-consuming, error-prone, and results in non-portable programs---given the technological diversity of quantum devices. In this thesis, I study problems related to the compilation of quantum programs, seeking forms of augmenting the expressive power of current frameworks and narrowing the gap between algorithmic research and concrete implementations. I focus on scalability and practicality---in particular, together with theoretical investigations, I developed concrete algorithms that are performant and scalable. The embodiment of my research contribution is a compiler companion library for the synthesis and compilation of quantum circuits called tweedledum.

EPFL2022

Cavity-mediated electron-photon pairs

Guanhao Huang, Tobias Kippenberg, Junqiu Liu, Zheru Qiu, Arslan Sajid Raja, Rui Ning Wang, Yujia Yang

Quantum information, communication, and sensing rely on the generation and control of quantum correlations in complementary degrees of freedom. Free electrons coupled to photonics promise novel hybrid quantum technologies, although single-particle correlations and entanglement have yet to be shown. In this work, we demonstrate the preparation of electron-photon pair states using the phase-matched interaction of free electrons with the evanescent vacuum field of a photonic chip-based optical microresonator. Spontaneous inelastic scattering produces intracavity photons coincident with energy-shifted electrons, which we employ for noise-suppressed optical mode imaging. This parametric pair-state preparation will underpin the future development of free-electron quantum optics, providing a route to quantum-enhanced imaging, electron-photon entanglement, and heralded single-electron and Fock-state photon sources.

AMER ASSOC ADVANCEMENT SCIENCE2022

Practical Compilation of Quantum Programs

Bruno Schmitt Antunes

EPFL2022

Practical Compilation of Quantum Programs

Cavity-mediated electron-photon pairs

Evaluating ESOP Optimization Methods in Quantum Compilation Flows

Practical Compilation of Quantum Programs

Evaluating ESOP Optimization Methods in Quantum Compilation Flows

Cavity-mediated electron-photon pairs