65 citations · 301 across the 33 of their papers we have counts for
23 papers · 1 filter
Fidelity-Based Robustness Margins for Finite-Time Quantum Control
S. P. O'Neil, F. C. Langbein, C. A. Weidner +2
We develop a structure-specific fidelity-threshold robustness margin for finite-dimensional closed quantum systems under piecewise-constant coherent control. A scalar physical para…
Energy Landscape Shaping for Robust Control of Atoms in Optical Lattices
C. A. Weidner, S. P. O'Neil, E. A. Jonckheere +2
Robust quantum control is crucial for realizing practical quantum technologies. Energy landscape shaping offers an alternative to conventional dynamic control, providing theoretica…
Robustness of Dynamic Quantum Control: Differential Sensitivity Bound
S. P. O'Neil, C. A. Weidner, E. A. Jonckheere +2
Dynamic control via optimized, piecewise-constant pulses is a common paradigm for open-loop control to implement quantum gates. While numerous methods exist for the synthesis of su…
Disturbance-agnostic robust performance with structured uncertainties and initial state error in classical versus quantum oscillatory systems
Edmond Jonckheere, Sophie G. Schirmer, Frank C. Langbein +2
A method to quantify robust performance for situations where structured parameter variations and initial state errors rather than extraneous disturbances are the main performance l…
Sample-efficient Model-based Reinforcement Learning for Quantum Control
Irtaza Khalid, Carrie A. Weidner, Edmond A. Jonckheere +2
We propose a model-based reinforcement learning (RL) approach for noisy time-dependent gate optimization with improved sample complexity over model-free RL. Sample complexity is th…
Analyzing and Unifying Robustness Measures for Excitation Transfer Control in Spin Networks
S. P. O'Neil, I. Khalid, A. A. Rompokos +4
Recent achievements in quantum control have resulted in advanced techniques for designing controllers for applications in quantum communication, computing, and sensing. However, th…
Robustness of Energy Landscape Control to Dephasing
Sean Patrick O'Neil, Frank C. Langbein, Edmond Jonckheere +1
As shown in previous work, in some cases closed quantum systems exhibit a non-conventional trade-off in performance and robustness in the sense that controllers with the highest fi…
Robustness of Energy Landscape Controllers for Spin Rings under Coherent Excitation Transport
Sean O'Neil, Frank Langbein, Edmond Jonckheere +1
The design and analysis of controllers to regulate excitation transport in quantum spin rings presents challenges in the application of classical feedback control techniques to syn…
Time Domain Sensitivity of the Tracking Error
S. O'Neil, S. G. Schirmer, F. C. Langbein +2
A strictly time-domain formulation of the log-sensitivity of the error signal to structured plant uncertainty is presented and analyzed through simple but representative classical…
Applying classical control techniques to quantum systems: entanglement versus stability margin and other limitations
C. A. Weidner, S. G. Schirmer, F. C. Langbein +1
Development of robust quantum control has been challenging and there are numerous obstacles to applying classical robust control to quantum system including bilinearity, marginal s…
Statistically Characterising Robustness and Fidelity of Quantum Controls and Quantum Control Algorithms
Irtaza Khalid, Carrie A. Weidner, Edmond A. Jonckheere +2
Robustness of quantum operations or controls is important to build reliable quantum devices. The robustness-infidelity measure (RIM) is introduced to statistically quantify the…
Robustness of Quantum Systems Subject to Decoherence: Structured Singular Value Analysis?
S G Schirmer, F C Langbein, C A Weidner +1
We study the problem of robust performance of quantum systems under structured uncertainties. A specific feature of closed (Hamiltonian) quantum systems is that their poles lie on…
Reinforcement Learning vs. Gradient-Based Optimisation for Robust Energy Landscape Control of Spin-1/2 Quantum Networks
I. Khalid, C. A. Weidner, E. A. Jonckheere +2
We explore the use of policy gradient methods in reinforcement learning for quantum control via energy landscape shaping of XX-Heisenberg spin chains in a model agnostic fashion. T…
Robustness of energy landscape control for spin networks under decoherence
S. Schirmer, E. Jonckheere, S. O'Neil +1
Quantum spin networks form a generic system to describe a range of quantum devices for quantum information processing and sensing applications. Understanding how to control them is…
Sensitivity and Robustness of Quantum Spin-1/2 Rings to Parameter Uncertainty
Sean O'Neil, Edmond Jonckheere, Sophie Schirmer +1
Selective transfer of information between spin-1/2 particles arranged in a ring is achieved by optimizing the transfer fidelity over a readout time window via shaping, externally a…
Structured singular value analysis for spintronics network information transfer control
Edmond A. Jonckheere, Sophie G. Schirmer, Frank C. Langbein
Control laws for selective transfer of information encoded in excitations of a quantum network, based on shaping the energy landscape using time-invariant, spatially-varying bias f…
Design of Feedback Control Laws for Information Transfer in Spintronics Networks
Sophie G Schirmer, Edmond Jonckheere, Frank C Langbein
Information encoded in networks of stationary, interacting spin-1/2 particles is central for many applications ranging from quantum spintronics to quantum information processing. W…
Time optimal information transfer in spintronics networks
Frank Langbein, Sophie Schirmer, Edmond Jonckheere
Propagation of information encoded in spin degrees of freedom through networks of coupled spins enables important applications in spintronics and quantum information processing. We…
The ubiquitous problem of learning system parameters for dissipative two-level quantum systems: Fourier analysis versus Bayesian estimation
Sophie Schirmer, Frank Langbein
We compare the accuracy, precision and reliability of different methods for estimating key system parameters for two-level systems subject to Hamiltonian evolution and decoherence.…
Information Transfer Fidelity in Spin Networks and Ring-based Quantum Routers
Edmond Jonckheere, Frank Langbein, Sophie Schirmer
Spin networks are endowed with an Information Transfer Fidelity (ITF), which defines an absolute upper bound on the probability of transmission of an excitation from one spin to an…
Characterization and Control of Quantum Spin Chains and Rings
Sophie Schirmer, Frank Langbein
Information flow in quantum spin networks is considered. Two types of control -- temporal bang-bang switching control and control by varying spatial degrees of freedom -- are explo…
Geometry and Curvature of Spin Networks
E Jonckheere, S G Schirmer, F C Langbein
A measure for the maximum quantum information transfer capacity (ITC) between nodes of a spin network is defined, and shown to induce a metric on a space of equivalence classes of…
Quantum System Identification: Hamiltonian Estimation using Spectral and Bayesian Analysis
S. G. Schirmer, F. C. Langbein
Identifying the Hamiltonian of a quantum system from experimental data is considered. General limits on the identifiability of model parameters with limited experimental resources…