Info - SpinNet

Info - SpinNet

We investigate robust quantum control of spin-1/2 quantum networks through optimization and control techniques, ranging from gradient-based optimization to reinforcement learning. In addition to dynamic control, we specifically focus on static energy landscape control. Controller robustness is evaluated using sensitivity and singular value analysis, and we pioneer novel avenues toward a theory of robust quantum control. This research also investigates the intrinsic properties of quantum spin networks.

We have contributed theory and efficient methods for

  • Characterizing the performance and robustness of quantum controls using statistical measures, differential and log sensitivity analysis, and structured singular value analysis.
  • Finding robust quantum controls using reinforcement learning and feedback control laws.
  • Investigating the geometric properties of quantum spin networks, including optimal information transfer and its connection to simultaneous Diophantine approximation.
  • Performing quantum process tomography with spectral and Bayesian analysis.

People

Publications

  • CA Weidner, SP O’Neil, EA Jonckheere, FC Langbein, SG Schirmer. Energy Landscape Shaping for Robust Control of Atoms in Optical Lattices. New J. Phys. 27 064503, 2025. [arXiv:2501.12564] [DOI:10.1088/1367-2630/addc0d] [PDF]
  • FC Langbein. Robust Quantum Control and Algorithms. QEVEC/QuANDiE Workshop: Quantum Algorithms for Fluids, Cardiff University, 7th March 2025.
  • CA Weidner, EA Reed, J Monroe, S O'Neil, E Maas, EA Jonckheere, FC Langbein, SG Schirmer. Robust Quantum Control in Closed and Open Systems: Theory and Practice. Automatica, 172:111987, 2025. [DOI:10.1016/j.automatica.2024.111987] [arXiv:2401.00294] [PDF]
  • SP O'Neil, CA Weidner, EA Jonckheere, FC Langbein, SG Schirmer. Robustness of Dynamic Quantum Control: Differential Sensitivity Bounds. AVS Quantum Sci 6:032001, 2024. [DOI:DOI:10.1116/5.0196110] [arXiv:2401.00301] [PDF]
  • S O'Neil, SG Schirmer, FC Langbein, CA Weidner, E Jonckheere. Time Domain Sensitivity of the Tracking Error. IEEE Transactions on Automatic Control, 69(4):2340-2351, 2024. [DOI:10.1109/TAC.2023.3331681] [arXiv:2210.15783] [PDF]
  • E Jonckheere, SG Schirmer, FC Langbein, CA Weidner, S O'Neil. Disturbance-agnostic robust performance with structured uncertainties and initial state error in classical versus quantum oscillatory systems. Preprint, 2023. [arXiv:2305.03918] [PDF]
  • FC Langbein. Finding and Characterising Robust Quantum Controls. Faculti interview with Frank Langbein on robust quantum control, 25th May 2023. [URL: https://faculti.net/finding-and-characterising-robust-quantum-controls/]
  • I Khalid, CA Weidner, EA Jonckheere, SG Shermer, FC Langbein. Sample-efficient Model-based Reinforcement Learning for Quantum Control. Phys Rev Research 5:043002, 2023. [DOI:10.1103/PhysRevResearch.5.043002] [arXiv:2304.09718] [PDF]
  • SP O'Neil, I Khalid, AA Rompokmos, CA Weidner, FC Langbein, S Schirmer, EA Jonckmheere. Analyzing and Unifying Robustness Measures for Excitation Transfer Control in Spin Networks. IEEE Control Systems Letters, 7:1783-1788, 2023. Also accepted for presentation at the IEEE Conf Decision and Control (CDC) 2023. [DOI:10.1109/LCSYS.2023.3279797] [arXiv:2303.09518] [PDF]
  • SP O'Neil, FC Langbein, E Jonckheere, SG Shermer. Robustness of Energy Landscape Control to Dephasing. Research Directions: Quantum Technologies 1:e13, 2023. [doi:10.1017/qut.2023.6] [arXiv:2303.05649] [PDF] [Video Abstract]
  • S O'Neil, FC Langbein, E Jonckheere, SG Shermer. Robustness of Energy Landscape Controllers for Spin Rings under Coherent Excitation Transport. Research Directions: Quantum Technologies 1:e12, 2023. [DOI:10.1017/qut.2023.5] [arXiv:2303.00142] [PDF] [Video Abstract]
  • I Khalid, C Weidner, SG Schirmer, E Jonckheere, FC Langbein. Sample-efficient Model-based Reinforcement Learning for Quantum Control. Poster at BQIT:23, 2023. [PDF:poster]
  • I Khalid, CA Weidner, EA Jonckheere, SG Shermer, FC Langbein. Statistically Characterising Robustness and Fidelity of Quantum Controls and Quantum Control Algorithms. Phys Rev A, 107:032606, 2023. [DOI:10.1103/PhysRevA.107.032606] [arXiv:2207.07801] [PDF]
  • E Jonckheere, SG Schirmer, FC Langbein, CA Weidner. Noiseless Robust Performance with Structured Uncertainties and Initial State Error. Preprint, 2022 [PDF]
  • AA Rompokos, FC Langbein, EA Jonckheere. Information Transfer in Spintronics Networks under Worst Case Uncertain Parameter Errors. IEEE Conf Decision and Control (CDC), pp. 5825-5830, 2022. [DOI:10.1109/CDC51059.2022.9993088] [PDF]
  • CA Weidner, SG Schirmer, FC Langbein, EA Jonckheere. Applying Classical Control Techniques to Quantum Systems: Entanglement versus Stability Margin and other Limitations. IEEE Conf Decision and Control (CDC), pp. 5813-5818, 2022. [DOI:10.1109/CDC51059.2022.9992337] [arXiv:2207.12385] [PDF] [Video Abstract]
  • SG Schirmer, FC Langbein, CA Weidner, EA Jonckheere. Robust Control Performance for Open Quantum Systems. IEEE Trans Automatic Control, 67(11):6012-6024, 2022. [DOI:10.1109/TAC.2022.3181249] [arXiv:2008.13691] [PDF]
  • I Khalid, C Weidner, SG Schirmer, E Jonckheere, FC Langbein. Finding and Characterising Robust Quantum Controls. Poster at BQIT:22, 2022. [PDF:poster]
  • FC Langbein. AI3SD Video: Learning to Control Quantum Systems Robustly, 10/11/2021. AI3SD Autumn Seminar Series 2021. 13 Oct - 15 Dec 2021. [DOI:10.5258/SOTON/AI3SD0163] [Video] [PDF:slides]
  • SG Schirmer, FC Langbein, CA Weidner, EA Jonckheere. Robustness of Quantum Systems Subject to Decoherence: Structured Singular Value Analysis?. IEEE Conf Decision and Control (CDC), pp. 4158-4163, 2021. [DOI:10.1109/CDC45484.2021.9682796] [arXiv:2110.05372] [PDF]
  • I Khalid, CA Weidner, EA Jonckheere, SG Schirmer, FC Langbein. Reinforcement Learning vs. Gradient-Based Optimisation for Robust Energy Landscape Control of Spin-1/2 Quantum Networks. IEEE Conf Decision and Control (CDC), pp. 4133-4139, 2021. [DOI:10.1109/CDC45484.2021.9683463] [arXiv:2109.07226] [PDF]
  • I Khalid, C Weidner, SG Schirmer, E Jonckheere, FC Langbein. Finding and Characterising Robust Quantum Controls. European Quantum Technologies Conference (EQTC), 2021. [PDF:poster] [PDF:abstract]
  • EA Jonckheere, SG Schirmer, FC Langbein. Effect of Quantum Mechanical Global Phase Factor on Error vs Sensitivity Limitation in Quantum Routing. IEEE Conf Decision and Control (CDC), pp. 1339-1344, 2019. [DOI:10.1109/CDC40024.2019.9029913] [PDF]
  • SG Schirmer, EA Jonckheere, S O’Neil, FC Langbein. Robustness of energy landscape control for spin networks under decoherence. IEEE Conf Decision and Control (CDC), pp. 6608-6613, 2018. [DOI:doi.org/10.1109/CDC.2018.8619179] [arXiv:1808.01256] [PDF]
  • EA Jonckheere, SG Schirmer, FC Langbein. Cover Image. Int J Robust and Nonlinear Control, 28(6), 2018. [DOI:10.1002/rnc.4085]
  • EA Jonckheere, SG Schirmer, FC Langbein. Jonckheere-Terpstra test for nonclassical error versus log-sensitivity relationship of quantum spin network controllers. Int J Robust and Nonlinear Control, 28(6):2383-2403, 2018. [DOI:10.1002/rnc.4022] [arXiv:1612.02784] [PDF]
  • SG Schirmer, EA Jonckheere, FC Langbein. Design of Feedback Control Laws for Information Transfer in Spintronics Networks. IEEE Trans Automatic Control, 63(8):2523-2536, 2018. [DOI:10.1109/TAC.2017.2777187] [arXiv:1607.05294] [PDF]
  • S O’Neil, EA Jonckheere, SG Schirmer, FC Langbein. Sensitivity and Robustness of Quantum Spin-1/2 Rings to Parameter Uncertainty. IEEE Conf Decision and Control (CDC), pp. 6137-6142, 2017. [DOI:10.1109/CDC.2017.8264584] [arXiv:1708.09649] [PDF]
  • EA Jonckheere, SG Schirmer, FC Langbein. Structured Singular Value Analysis for Spintronics Network Information Transfer Control. IEEE Trans Automatic Control, 62(12):6568-6574, 2017. [DOI:10.1109/TAC.2017.2714623] [arXiv:1706.03247] [PDF]
  • P Bogdan, EA Jonckheere, SG Schirmer. Multi-fractal Geometry of Finite Networks of Spins. Chaos, Solitons and Fractals, 103:622-631, 2017. [DOI:10.1016/j.chaos.2017.07.008] [arXiv:1608.08192] [PDF]
  • FC Langbein, SG Schirmer, EA Jonckheere. Time optimal information transfer in spintronics networks. IEEE Conf Decision and Control (CDC), pp. 6454-6459, 2015. [DOI:10.1109/CDC.2015.7403236] [arXiv:1508.00928] [PDF]
  • EA Jonckheere, FC Langbein, SG Schirmer. Information Transfer Fidelity in Spin Networks and Ring-based Quantum Routers. Quantum Information Processing, 14(12):4761-4785, 2015. [DOI:10.1007/s11128-015-1136-4] [arXiv:1408.3765] [PDF]
  • SG Schirmer, FC Langbein. The ubiquitous problem of learning system parameters for dissipative two-level quantum systems: Fourier analysis versus Bayesian estimation. Phys Rev A, 91:022125, 2015. [DOI:10.1103/PhysRevA.91.022125] [arXiv:1412.4282] [PDF]
  • SG Schirmer, FC Langbein. Characterization and Control of Quantum Spin Chains and Rings. Int Symp Communications, Control and Signal Processing, pp. 615 – 619, 2014. [DOI:10.1109/ISCCSP.2014.6877950] [arXiv:1403.0226] [PDF]
  • EA Jonckheere, FC Langbein, SG Schirmer. Quantum networks: Anti-core of spin chains. Quantum Information Processing, 13(7):1607-1637, 2014. [DOI:10.1007/s11128-014-0755-5] [arXiv:1403.0159] [PDF]
  • EA Jonckheere, FC Langbein, SG Schirmer. Curvature of quantum rings. Int Symp Communications Control and Signal Processing, pp. 1-6, 2012. [DOI:10.1109/ISCCSP.2012.6217863] [arXiv:1202.2556] [PDF]
  • EA Jonckheere, SG Schirmer, FC Langbein. Geometry and Curvature of Spin Networks. IEEE Int Conf Control Applications, pp. 786-791, 2011. [DOI:10.1109/CCA.2011.6044395] [arXiv:1102.3208] [PDF]
  • FC Langbein, SG Schirmer. Quantum Engineering: From Einstein’s Spooky Action to Sustainable Technology? IEEE GOLDRush newsletter, peer-reviewed contribution, pp. 14-15, September 2010. [DOI:10.13140/RG.2.1.4109.1921] [Published] [PDF]
  • SG Schirmer, FC Langbein. Quantum System Identification: Hamiltonian Estimation using Spectral and Bayesian Analysis. Int Symp Communications, Control and Signal Processing, pp. 1-5, 2010. [DOI:10.1109/ISCCSP.2010.5463437] [arXiv:0911.5429] [PDF]

PhDs

  • Sean O'Neil. Robust Control of Quantum Systems. Department of Electrical Engineering. University of Southern California, ongoing.
  • Irtaza Khalid. Machine Learning methods for Robust Quantum Optimal Control. PhD thesis, Cardiff University, 2024. [PDF]

Reports

  • J Misra. Robust Quantum Control via Optimising a Stochastic Target Functional. BSc Computer Science dissertation, Cardiff University, 2023. [Archive]
  • J Misra, FC Langbein. Analysing the Robustness of Controllers for Information Transfer in Quantum Spin-1/2 Networks. Summer Research Internship in Quantum Control at Cardiff University, 2022. [Details]
  • V Manivasagam. Quantum Error Correction vs. Robust Quantum Control. MSc Advanced Computer Science, Cardiff Univerrsity, 2021.
  • M Esposito. Robust Quantum Controllers and Simulation. BSc Computer Science dissertation, Cardiff University, 2021. [Archive]
  • N Zaidi. Investigation into the robustness of static quantum controls with the introduction of uncertainty. BSc Computer Science dissertation, Cardiff University, 2021. [Archive]
  • A Ugaste. Reinforcement Learning Algorithms for Controlling Quantum Spin-1/2 Networks. BSc Computer Science dissertation, Cardiff University, 2021. [Archive]
  • B Uttley. Quantum Spin Network Simulator. BSc Computer Science dissertation, Cardiff University, 2019.
  • K Dimou. Visualising Quantum Control Landscapes. MSc Computer Science dissertation, Cardiff University, 2017.
  • P Davison. Parallelisation of Matrix Exponentials in C++/CUDA for Quantum Control. BSc Computer Science dissertation, Cardiff University, 2016. [Archive]
  • M Chandler. Parallelising the L-BFGS algorithm on GPUs for Quantum Control problems. BSc Computer Science dissertation, Cardiff University, 2015. [Archive]

Code and Results

Data

Workshops

  • Quantum Technology: Computational Models for Quantum Device Design (12w5061). Banff International Research Stations for Mathematical Innovation and Discovery, January 8-13, 2012. [Details]
  • NSEW 2008: Quantum Engineering. Practical Applications of Quantum Physics and How these Might Transform Society. A lecture on the fundamentals of quantum physics with hands-on demonstrations and a discussion of the potential impact of quantum technology on everyone’s life. [Details]

Funding

  • May 2023 - May 2025: Robust, Trapped Ultracold Atom Interferometry For Six-axis Inertial Sensing. EPSRC EP/Y004728/1. PI: CA Weider. CoI: A Clark, S Schirmer, FC Langbein. £579,418. [Details]
  • October 2020, 3 years: Cardiff University, School of Computer Science and Informatics PhD Scholarship. Irtaza Khalid.
  • September 2018 – August 2020: US-UK International Student Research in Robust Control of Quantum Networks. PI: EA Jonckheere (University of Southern California) with SG Schirmer (Swansea University) and FC Langbein (Cardiff University). NSF #1829078 OISE IRES ASI – Track II. USD164,503. [Details]
  • August 2014 – August 2015: Cardiff University Research Leave Fellowship. PI: FC Langbein (Cardiff University). Teaching replacement costs and £3,000 support. [Details]
  • August 2012 – July 2015: QUAINT – Optimal Control Technologies in Quantum Information Processing. Coordinator: University of Southampton (I. Kuprov) with Univerzita Karlova v Praze, Czech Republic, Universität Ulm, Germany, Karlsruher Institut fuer Technologie, Germany, Universität des Saarlandes, Germany, Universität Kassel, Germany, Technisch Universität München, Germany, Aarhus Universitet, Denmark, Universite de Bourgogne, France, Centre National de la Recherche Scientifique, France, The Hebrew University of Jerusalem, Israel, Weizmann Institute of Science, Israel, The University of Nottingham, UK, Cardiff University, UK, Swansea University, UK. FP7-ICT-2011-C, ICT-2011.9.1 – Challenging current Thinking, CSA – Coordination & support action, ref 297861. EUR 399,901. [Details]
  • 2009-2013: RIVIC: One Wales Research Institute for Visual Computing. WAG (HEFCW) via Bangor University. Consortium: RR Martin, NJ Avis, AD Marshall, PL Rosin, FC Langbein at Cardiff University, with Bangor University (lead), Aberystwyth University, Swansea University. £998,011. [Details]
  • 2008: Quantum engineering – practical applications of quantum physics and how these might transform society. PI: FC Langbein (Cardiff University) with SG Schirmer (Swansea University). Welsh Assembly Government via the BA, National Science and Engineering Week. £500. [Details]

Locations

The wiki is written and maintained on Qyber\black at https://qyber.black/pca/info-spinnet/.

Contact

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License

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