An International Network on Quantum Annealing
Register now for the upcoming INQA conference 9-11 November in London!
The International Network on Quantum Annealing (INQA) will for the first time establish a mechanism by which four global collaborations come together to share technical and intellectual know-how and critically analyse developments in theoretical and experimental research in quantum annealing.
- 27th September 2022 | 16:00 UTC | Adolfo del Campo | University of Luxembourg
Universal dynamics of open quantum phase transitions in a quantum annealer
The number of topological defects created in a system driven through a quantum phase transition exhibits a power-law scaling with the driving time. This universal scaling law is the key prediction of the Kibble-Zurek mechanism (KZM), and testing it using a hardware-based quantum simulator is a coveted goal of quantum information science. Here we provide such a test using quantum annealing. Specifically, we report on extensive experimental tests of topological defect formation via the one-dimensional transverse-field Ising model on two different D-Wave quantum annealing devices. We find that the quantum simulator results can indeed be explained by the KZM for open-system quantum dynamics with phase-flip errors, with certain quantitative deviations from the theory likely caused by factors such as random control errors and transient effects. In addition, we probe physics beyond the KZM by identifying signatures of universality in the distribution and cumulants of the number of kinks and their decay, and again find agreement with the quantum simulator results. This implies that the theoretical predictions of the generalized KZM theory, which assumes isolation from the environment, applies beyond its original scope to an open system. We support this result by extensive numerical computations. To check whether an alternative, classical interpretation of these results is possible, we used the spin-vector Monte Carlo model as well as the spin-vector Langevin model, both candidate classical descriptions of the D-Wave device. Our work provides an experimental test of quantum critical dynamics in an open quantum system, and paves the way to new directions in quantum simulation experiments.
- 5th October 2022 | 00:01 UTC | Eliot Kapit | Colorado School of Mines
Noise tolerant quantum speedups in quantum annealing without fine tuning
Quantum annealing (QA) is a promising method to solve hard optimization problems with quantum hardware, without the need for fault tolerance and topological error correction. However, despite great effort it has thus far failed to achieve broadly applicable quantum advantage in practical problems. We identify four key issues as the likely reason for this, two of which are engineering challenges and two of which are deeper physics problems. We propose a novel modification, called RFQA, which we argue will solve or at least mitigate the core physics issues in ordinary QA. This modification applies low-frequency oscillating terms independently to every qubit in the system, which results in an exponential proliferation of weak resonances that accelerates the first order phase transitions that bottleneck QA. This novel quantum speedup mechanism allows for faster thermalization in glassy problems; we present a mix of analytical and numerical results demonstrating this. Implemented at scale, RFQA would thus be an extremely promising route to achieving near-term quantum advantage in practical problems.
If you miss any of our live seminars you can watch our previous sessions on our YouTube Channel.
Visit past seminars to view a list of all of our past seminars and their abstracts.
The INQA network unifies the research activities of major global collaborations in quantum annealing in North America, Japan, the European Union and the United Kingdom.
By hosting weekly on-line seminars and annual international conferences and by funding exchange visits, the INQA network will address the key topics which will enable quantum annealing to move towards a true quantum scaling advantage over classical approaches to NP-hard computational problems.
The topics INQA will focus on include:
- Exploiting quantum coherence,
- Extending the order and degree of qubit interactions,
- Strategies for error correction and,
- Exploiting diabaticity and non-stoquasticity in a systematic way.
The network will be led by Professor Paul Warburton of UCL, who is a co-investigator in the UK’s Quantum Computation and Simulation (QCS) Hub and in the recently-announced QEVEC project. He was also previously a co-investigator in the US-led QEO and QAFS collaborations.
Members of the management board include:
- Prof Paul Warburton (UCL, UK)
- Dr Pol Forn-Díaz (IFAE, Spain)
- Dr Shiro Kawabata (AIST, Japan)
- Prof Viv Kendon (University of Strathclyde, UK)
- Dr Jamie Kerman (MIT Lincoln Lab, USA)
INQA is supported by a International Network Grant from the UK Engineering and Physical Sciences Research Council.
Keep up-to-date with meetings, news and events by joining INQA.