Closing the gaps in Quantum Computing: Co-Development and Co-Design

Alexandre M. Zagoskin

Frederic T. Chong

Yunong Shi

Quantum computing has recently transitioned from a theoretical prediction to a nascent technology. Nevertheless, there is still a gap between the computational ability and reliability of current QIP technologies and the requirements of the first useful quantum computing applications. It will require tremendous efforts and investment to solve the engineering and research challenges to close the gap. Because of the uncertainties and difficulties in relying on hardware breakthroughs, it will also be crucial to close the gap using higher-level quantum optimizations and software-hardware co-design, which could maximally utilize noisy devices and potentially provide an accelerated pathway to real-world quantum computing applications. This thesis develops methods to explore the vast design space for highly optimized and reliable quantum computing architectures and software and focuses on the compilation, verification, and error correction aspects of the quantum computing stack. Specifically, the three main chapters in this thesis discuss, respectively, a direct-to-pulse compiler, a protocol to fault-tolerantly prepare approximate GKP (Gottesman-Kitave-Preskill) qubit states, and a verification framework that helps quantum programmers write provably correct compiler components through formal verification. Though touching many aspects of the stack and based on different technologies in physics and computer science, the majority of this thesis can be connected by a main theme --- improving the efficiency of existing quantum computing stacks by breaking the abstraction between layers in the quantum computing stack.

Nicole Holzmann

Quantum computing is a deep technology whose progress cannot be driven effectively from one direction alone. While the field has developed a growing catalogue of mathematically grounded algorithmic speedups, industrial impact will depend just as much on starting from real industrial decision contexts and working downward to what must be computed, validated and integrated. In this Perspective, I argue that sustained progress requires treating these two directions: bottom-up development from physics, hardware and algorithms, and top-down development from industrial needs and constraints. Equally primary and continuously coupled. This dual-viewpoint is not a matter of balance for its own sake. Quantum computers cannot solve arbitrary problems, so engagement with industry must remain anchored in algorithmic tractability. Yet tractable computations are rarely valuable unless they connect to decision points in established workflows such as candidate selection in drug discovery or the design of a new aircraft shape with improved aerodynamics. I analyse how historical narratives and structural separations of expertise slowed the formation of this coupling and outline what it takes to build it: explicit interfaces between technical teams and domain context and intermediate layers that translate quantum outputs into decision-relevant observables without suffocating foundational innovation. Framed this way, quantum computing's opportunity is clearest where deep physical modelling meets high-value decisions. Provided the field co-designs both sides from the outset.

Andreas H. Trabesinger

Frederic T. Chong

Quantum computing is at an inflection point, where 127-qubit machines are deployed, and 1000-qubit machines are only a few years away. These machines have the potential to fundamentally change our concept of what is computable and demonstrate practical applications in areas such as quantum chemistry, optimization, and quantum simulation.