Quantum physics governs the behaviour of matter and energy at the atomic and subatomic levels.
Quantum control allows us to steer and engineer these systems to achieve specific goals, such as carrying out a complex computation or simulation, detecting tiny variations in biological molecules or understanding how proteins work at the molecular level.
We develop algorithms and theories to find high-fidelity, robust quantum controls, understand their capabilities and limitations, and improve our knowledge of the underlying processes. We pursue applications of robust quantum controls to engineer computational devices and sensors, understand biological and chemical processes, and improve medical diagnosis and treatments.
To advance quantum control and its applications we have contributed theory and efficient methods for:
- characterising the performance and robustness of quantum controls using statistical measures, differential and log sensitivity analysis, and structured singular value analysis
- designing chemically specific magnetic resonance spectroscopy pulse sequences via quantum control and metabolite quantification via deep learning
- 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.
The group is part of the Qyber research network with our latest news, updates, and results.
Research
We are actively conducting research on the following topics:
- robustness of energy landscape (static) and dynamic quantum control
- reinforcement learning to find robust, high-fidelity (low error) quantum controls
- explainable and lightweight models of physical, chemical and biological processes from measurements
- dynamics of quantum networks of interacting spin-1/2 particles
- ultracold trapped atoms for sensing and simulation
- magnetic resonance spectroscopy for metabolite quantification and biomarkers
- robust, early-stage cancer diagnosis and explainable artificial intelligence.
Projects
Our work has been supported by various UKRI/EPSRC, European Union, NSF, Sêr Cymru National Research Networks, and individual PhD student grants. Our current projects include:
- SpinNET: Optimal control of spin network dynamics and characterisation of the network dynamics, including robust quantum control, energy landscape control schemes, and reinforcement learning approaches.
- Robust, trapped ultracold atom interferometry for six-axis inertial sensing: Demonstrate inertial sensing with shaken lattice interferometry using ultracold atoms trapped in an optical lattice.
- MRSNet: Machine learning and quantum control for metabolite quantification in magnetic resonance spectroscopy.
- BCa and PCaNet: Prostate and brain cancer diagnosis in multi-parametric magnetic resonance imaging and spectroscopy focused on early-stage cancers, including investigating the robustness of machine learning diagnosis, computationally lightweight machine learning approaches, and explainable artificial intelligence.
- Quantum Spintronics: Simulation of spin-orbit coupling with a Monte Carlo semiconductor device simulator and coherent control of electron spin polarisation.
Seminars from members and visitors are presented at the Visual computing research seminars and Qyber Workshops.
Meet the team
Lead researcher
Academic staff
Postgraduate students
Related partners
- Mark Davies, Swansea Bay University Health Board
- Edmond Jonckheere, Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California
- Sophie Shermer, Physics, Swnasea University
- Carrie Weidner, School of Physics and School of Electrical, Electronic and Mechanical Engineering, University of Bristol
Publications
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, in press, 2024.
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.
A Muftah, SM Shermer, FC Langbein. Texture Feature Analysis for Classification of Early-Stage Prostate Cancer in mpMRI. Proc AI in Healthcare (AIiH), LNCS 14976:118-131, Swansea, UK, September 2024.
E Alwadee, X Sun, Y Qin, FC Langbein. Assessing and Enhancing the Robustness of Brain Tumor Segmentation using a Probabilistic Deep Learning Architecture. Proc 2024 ISMRM & ISMRT Annual Meeting & Exhibition, Singapore, May 2024.
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.
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.
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.
SP O'Neil, FC Langbein, E Jonckheere, SG Shermer. Robustness of Energy Landscape Control to Dephasing. Research Directions: Quantum Technologies 1:e13, 2023.
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.
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.
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.
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.
SG Schirmer, FC Langbein, CA Weidner, EA Jonckheere. Robust Control Performance for Open Quantum Systems. IEEE Trans Automatic Control, 67(11):6012-6024, 2022.
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.
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.
I Khalid, C Weidner, SG Schirmer, E Jonckheere, FC Langbein. Finding and Characterising Robust Quantum Controls. European Quantum Technologies Conference (EQTC), 2021.
JE Evans, G Burwell, FC Langbein, SG Shermer, K Kalna. Dilute Magnetic Contact for a Spin GaN HEMT. In: Semiconductor and Integrated OptoElectronics Conference (SIOE), Cardiff, 16-18th April, 2019.
C Jenkins, M Chandler, FC Langbein, SM Shermer. Quantification of edited magnetic resonance spectroscopy: a comparative phantom based study of analysis methods. ISMRM 27th Annual Meeting & Exhibition, Montréal, QC, Canada, 11th-16th May 2019.
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.
B Thorpe, SG Schirmer, K Kalna, FC Langbein. Monte Carlo Simulations of Spin Transport in an InGaAs Field Effect Transistor. In: 34th Int. Conf. Physics of Semiconductors (ICPS2018), Poster P3_176, 29th July to 3rd August 2018.
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.
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.
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.
B Thorpe, K Kalna, FC Langbein, SG Schirmer. Spin Recovery in the 25nm Gate Length InGaAs Field Effect Transistor. In: Proc. Int. Workshop on Computational Nanotechnology, pp. 168-169, Windermere, UK, 6-9th June, 2017.
SM Schirmer, FC Langbein, C Jenkins, M Chandler. Design of novel MRI pulse sequences for GABA quantification using optimal control. Proc 4th Int Symp on MRS of GABA, 2017.
B Thorpe, K Kalna, FC Langbein, SG Schirmer. Monte Carlo Simulations of Spin Transport in Nanoscale InGaAs Field Effect Transistors. J Applied Physics, 122, 223903, 2017.
B Thorpe, SG Schirmer, K Kalna, FC Langbein. Monte Carlo simulation of Spin Transport and Recovery in a 25 nm gate length InGaAs Field Effect Transistor. In: European Materials Research Society 2017 Fall Meeting, Symposium F: Spintronics in semiconductors, 2D materials and topological insulators, F.FP.7, 2017.
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.
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.
FC Langbein, SG Schirmer, EA Jonckheere. Time optimal information transfer in spintronics networks. IEEE Conf Decision and Control (CDC), pp. 6454-6459, 2015.
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.
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.
SG Schirmer, FC Langbein. Characterization and Control of Quantum Spin Chains and Rings. Int Symp Communications, Control and Signal Processing, pp. 615-619, 2014.
EA Jonckheere, FC Langbein, SG Schirmer. Quantum networks: Anti-core of spin chains. Quantum Information Processing, 13(7):1607-1637, 2014.
EA Jonckheere, FC Langbein, SG Schirmer. Curvature of quantum rings. Int Symp Communications Control and Signal Processing, pp. 1-6, 2012.
EA Jonckheere, SG Schirmer, FC Langbein. Geometry and Curvature of Spin Networks. IEEE Int Conf Control Applications, pp. 786-791, 2011.
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.
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