Software tools for quantum control: Improving quantum computer performance through noise and error suppression

Ball, Harrison; Biercuk, Michael J.; Carvalho, André F.; Chen, Jiayin; Hush, Michael; Castro, Leonardo Andreta de; Li, Li; Liebermann, Per J.; Slatyer, Harry J.; Edmunds, Claire; Frey, Virginia; Hempel, Cornelius; Milne, Alistair

doi:10.48550/arxiv.2001.04060

Cited by 18 publications

(33 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…FFs were originally introduced to compute the decay of phase coherence under dynamical decoupling sequences [16][17][18][19] consisting of wait times and perfect π-pulses. For small noise strengths, they were perturbatively extended to quantum gates [20][21][22][23] to compute gate fidelities [21,22,24] and develop strategies for noise mitigation [11,[25][26][27]. Here, we build on these results to compute quantum processes for gates and gate sequences on an arbitrary number of qubits and to analyse their concatenation properties.…”

Section: Introductionmentioning

confidence: 99%

Filter Functions for Quantum Processes under Correlated Noise

Cerfontaine,

Hangleiter,

Bluhm

2021

Preprint

View full text Add to dashboard Cite

Many qubit implementations are afflicted by correlated noise not captured by standard theoretical tools that are based on Markov approximations. While independent gate operations are a key concept for quantum computing, it is actually not possible to fully describe noisy gates locally in time if noise is correlated on times longer than their duration. To address this issue, we develop a method based on the filter function formalism to perturbatively compute quantum processes in the presence of correlated classical noise. We derive a composition rule for the filter function of a sequence of gates in terms of those of the individual gates. The joint filter function allows to efficiently compute the quantum process of the whole sequence. Moreover, we show that correlation terms arise which capture the effects of the concatenation and thus yield insight into the effect of noise correlations on gate sequences. Our generalization of the filter function formalism enables both qualitative and quantitative studies of algorithms and state-of-the-art tools widely used for the experimental verification of gate fidelities like randomized benchmarking, even in the presence of noise correlations.

show abstract

Section: Introductionmentioning

confidence: 99%

Filter Functions for Quantum Processes under Correlated Noise

Cerfontaine,

Hangleiter,

Bluhm

2021

Preprint

View full text Add to dashboard Cite

show abstract

“…The formalism facilitated recognizing these sequences as band-pass filters that allow for probing the environmental noise characteristics of a quantum system through noise spectroscopy [12,[21][22][23] or optimizing sequences to suppress specific noise bands [24][25][26][27]. It can also be extended to fidelities of gate operations for single [28,29] or multiple [30,31] qubits using the ME [32,33] as well as more general DD protocols [34]. The works by Green et al [29] and Clausen et al [35] also introduced the notion of the control matrix as a quantity closely related to the canonical filter function that is convenient for calculations.…”

Section: Introductionmentioning

confidence: 99%

Filter Function Formalism and Software Package to Compute Quantum Processes of Gate Sequences for Classical Non-Markovian Noise

Hangleiter,

Cerfontaine,

Bluhm

2021

Preprint

View full text Add to dashboard Cite

Correlated, non-Markovian noise is present in many solid-state systems employed as hosts for quantum information technologies, significantly complicating the realistic theoretical description of these systems. In this regime, the effects of noise on sequences of quantum gates cannot be described by concatenating isolated quantum operations if the environmental correlation times are on the scale of the typical gate durations. The filter function formalism has been successful in characterizing the decay of coherence under the influence of such classical, non-Markovian environments and here we show it can be applied to describe unital evolution within the quantum operations formalism. We find exact results for the quantum process and a simple composition rule for a sequence of operations. This enables the detailed study of effects of noise correlations on algorithms and periodically driven systems. Moreover, we point out the method's suitability for numerical applications and present the open-source Python software package filter_functions. Amongst other things, it facilitates computing the noise-averaged transfer matrix representation of a unital quantum operation in the presence of universal classical noise for arbitrary control sequences. We apply the presented methods to selected examples.

show abstract

“…Concurrent with our work, the startup Q-CTRL developed a software with similar methods but pursued a different strategy and targeted a commercial audience [39]. As for qopt, these methods include generalized filter functions and the simulation of noise by explicitly sampling noise distributions as Monte Carlo simulations.…”

Section: Introductionmentioning

confidence: 99%

qopt: An experiment-oriented Qubit Simulation and Quantum Optimal Control Package

Teske,

Cerfontaine,

Bluhm

2021

Preprint

View full text Add to dashboard Cite

Realistic modeling of qubit systems including noise and constraints imposed by control hardware is required for performance prediction and control optimization of quantum processors. We introduce qopt, a software framework for simulating qubit dynamics and robust quantum optimal control considering common experimental situations. To this end, we model open and closed qubit systems with a focus on the simulation of realistic noise characteristics and experimental constraints. Specifically, the influence of noise can be calculated using Monte Carlo methods, effective master equations or with the efficient filter function formalism, which enables the investigation and mitigation of autocorrelated noise. In addition, limitations of control electronics including finite bandwidth effects as well as nonlinear transfer functions and drive-dependent noise can be considered. The calculation of gradients based on analytic results is implemented to facilitate the efficient optimization of control pulses. The software easily interfaces with QuTip, is published under an open source license, well-tested and features a detailed documentation.

show abstract

Software tools for quantum control: Improving quantum computer performance through noise and error suppression

Cited by 18 publications

References 0 publications

Filter Functions for Quantum Processes under Correlated Noise

Filter Functions for Quantum Processes under Correlated Noise

Filter Function Formalism and Software Package to Compute Quantum Processes of Gate Sequences for Classical Non-Markovian Noise

qopt: An experiment-oriented Qubit Simulation and Quantum Optimal Control Package

Contact Info

Product

Resources

About