Hardware-Centric Tightly-Coupled Quantum/Classical Computations
A hardware description language for quantum computing
Time: Wed 2026-06-10 14.00
Location: D3, Lindstedtsvägen 5, Stockholm
Video link: https://kth-se.zoom.us/s/69771296581
Language: English
Subject area: Computer Science
Doctoral student: Gilbert Netzer , Parallelldatorcentrum, PDC, Beräkningsvetenskap och beräkningsteknik
Opponent: Assistant Professor Rafael Ferreira da Silva, Oak Ridge National Laboratory: Oak Ridge, Tennessee, USA
Supervisor: Professor Stefano Markidis, Beräkningsvetenskap och beräkningsteknik; Professor Erwin Laure, Max Planck Society: Munich, DE
QC 20260513
Abstract
By exploiting quantum mechanical behavior, quantum computers have the potential to carry out classically hard computations, such as the prime factorization of integers, with disruptive, exponentially better efficiency, yet they struggle with classically simple task like integer addition. Hybrid applications, combining both quantum and classical computations, attempt to take advantage of the strength of both approaches while avoiding their weaknesses. In such applications, the design of the interface between quantum and classical computers deserves attention as a potential performance bottleneck.
In this thesis, the design of a modular software stack for hybrid quantum/classical applications that is agnostic to the used quantum technology platform is developed both for high-level application-oriented as well as high-performance low-level use-cases. A hardware description language for quantum circuits derived from the industry standard VHDL language is proposed, and its usage in tightly-coupled hybrid applications, where quantum and classical computations overlap in time, is discussed. To enable low-latency coupling, the proposed hybrid architecture connects quantum computations to hardware implementations of timing critical classical computations and utilizes established hardware/software co-design patterns to interface higher-level classical computations.
Experimental evidence of noise effects on state-of-the-art quantum hardware is presented for the case of solving partial differential equations. This supports the conclusion that frequent interaction between short and shallow quantum and classical computations is necessary even for loosely-coupled hybrid applications under these circumstances, strengthening the case for a low-latency, high-bandwidth quantum-classical interface as proposed in this thesis.