Quantum information processing offers significant advantages over classical methods, especially in computation, cryptography, communication, and sensing. Recently, alternative approaches using bosons as information carriers have gained traction due to their potential for fault-tolerance and scalability. For instance, bosonic modes of light enable the generation of large entangled quantum states, while superconducting microwave fields provide avenues for quantum error correction. Quantum devices can only realize their full potential if they operate with high precision. Quantum verification ensures the correct functioning and accuracy of these devices, which is crucial for their effective use. As quantum devices become more accessible, robust verification methods will be essential for maintaining the privacy and integrity of quantum computations for end-users.
The urgency for efficient quantum verification methods is underscored by the need to demonstrate the first major quantum advantage (quantum speedup), is a milestone in the development of quantum computers. Despite ongoing efforts, achieving verified quantum speedup remains challenging. Efficient and rigorous verification thus remains a bottleneck in demonstrating quantum speedup and in scaling up quantum computers to solve real-world problems.
Quantum verification protocols typically involve numerous measurements of a device’s output to analyse its performance. However, general-purpose methods like tomography require impractically large numbers of measurements. This presents a major obstacle to the development of large-scale quantum technologies. Alternative approaches are therefore required.
In 2020, a theoretical breakthrough by the project coordinator led to the following idea: large bosonic quantum devices can be verified efficiently using continuous-variable (CV) quantum measurements, avoiding the exponential cost in terms of measurement samples. Although further development is needed to make these methods practical, this hints at the possibility of developing practical and efficient quantum verification methods for bosonic quantum computing architectures based on CV measurements. These measurements are already used in state-of-the-art quantum cryptography and communication protocols, but are rarely applied to quantum verification and computing.
The VeriQuB consortium will develop a state-of-the-art verification toolbox consisting of two main components: (1) an experimental demonstration of the verification of multimode bosonic systems for both optical and superconducting architectures, including the first verified quantum computational speedup; and (2) a theoretical framework outlining the fundamental advantages of VeriQuB’s contributions while identifying resourceful bosonic quantum devices.
Website:
https://veriqub.eu(opens in new window)
