Optimization of a solid-state electron spin qubit using gate set tomography

Dehollain, Juan Pablo; Muhonen, Juha T.; Blume-Kohout, Robin; Rudinger, Kenneth; Gamble, John King; Nielsen, Erik; Laucht, Arne; Simmons, Stephanie; Kalra, Rachpon; Dzurak, A. S.; Morello, Andrea

doi:10.1088/1367-2630/18/10/103018

Cited by 81 publications

(85 citation statements)

References 41 publications

(85 reference statements)

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“…Clearly the observed performance of experimental GST in the presence of correlatedσ x noise, such as resulting from experimental overrotations, can make GST a valuable tool in debugging an experimental system, 25 although precise calibrations can also be carried out efficiently using a subset of the full experimental GST protocol. 26 The effect of gauge optimisation in the presence ofσ z errors and with use of the default gate set, however, is concerning as a key implied benefit of experimental GST is its ability to provide a rigorous upper bound on gate errors using a fully self-contained analysis package.…”

Section: Discussionmentioning

confidence: 99%

Experimental quantum verification in the presence of temporally correlated noise

et al. 2018

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Growth in the capabilities of quantum information hardware mandates access to techniques for performance verification that function under realistic laboratory conditions. Here we experimentally characterise the impact of common temporally correlated noise processes on both randomised benchmarking (RB) and gate-set tomography (GST). Our analysis highlights the role of sequence structure in enhancing or suppressing the sensitivity of quantum verification protocols to either slowly or rapidly varying noise, which we treat in the limiting cases of quasi-DC miscalibration and white noise power spectra. We perform experiments with a single trapped 171 Yb + ion-qubit and inject engineered noise /σ z ð Þto probe protocol performance. Experiments on RB validate predictions that measured fidelities over sequences are described by a gamma distribution varying between approximately Gaussian, and a broad, highly skewed distribution for rapidly and slowly varying noise, respectively. Similarly we find a strong gate set dependence of default experimental GST procedures in the presence of correlated errors, leading to significant deviations between estimated and calculated diamond distances in the presence of correlatedσ z errors. Numerical simulations demonstrate that expansion of the gate set to include negative rotations can suppress these discrepancies and increase reported diamond distances by orders of magnitude for the same error processes. Similar effects do not occur for correlatedσ x orσ y errors or depolarising noise processes, highlighting the impact of the critical interplay of selected gate set and the gauge optimisation process on the meaning of the reported diamond norm in correlated noise environments.

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Section: Discussionmentioning

confidence: 99%

Experimental quantum verification in the presence of temporally correlated noise

et al. 2018

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“…Extensions of randomized benchmarking to non-Clifford gates have been proposed too [21][22][23]. Gate set tomography [24][25][26][27][28], on the other hand, is a sophisticated method which delivers simultaneously the fidelities of a set of gates.…”

Section: Introductionmentioning

confidence: 99%

Relations between single and repeated qubit gates: coherent error amplification for high-fidelity quantum-gate tomography

Vitanov

2020

New J. Phys.

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Keywords: quantum control, coherent control, quantum dynamics, quantum gates, quantum tomography, high fidelity N 2 , i.e. dramatically faster than the classical probability estimate. In the general case, however, the relation between the single-pass and N-pass propagators is much more involved. Recipes are proposed for unambiguous determination of the gate errors in the general case for both Clifford and non-Clifford gates.

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“…In the circuit model of quantum computing, a computation is represented as a sequence of primitive quantum logic operations or 'gates', each of which is implemented via a controlled quantum process. Characterization of these processes essential to assessing and improving their performance [2][3][4][5]. The paradigmatic way of characterizing a process involving some quantum system of interest is quantum process tomography (QPT) [6].…”

Section: Introductionmentioning

confidence: 99%

“…The execution of an arbitrary gate sequence is then modeled as a corresponding sequence of quantum channels on the device's qubits. While newer and more robust characterization methods such as gate set tomography (GST) [3,5,7] and randomized benchmarking (RB) [4,[8][9][10][11][12][13][14] have largely replaced QPT, these methods continue the approach of modeling each gate as a quantum channel involving only the targeted qubits.…”

Section: Introductionmentioning

confidence: 99%

“…While the theory of non-Markovian quantum dynamics has received growing attention in recent years [16,17], experimental strategies for characterizing such dynamics [18][19][20] are less well developed. Meanwhile, incoherent (Markovian) noise processes in quantum information technologies have been reduced to the point that non-Markovian errors are starting to becoming significant [3,5].…”

Section: Introductionmentioning

confidence: 99%

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Quantum process identification: a method for characterizing non-markovian quantum dynamics

Bennink

Lougovski

2019

New J. Phys.

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Established methods for characterizing quantum information processes do not capture non-Markovian (history-dependent) behaviors that occur in real systems. These methods model a quantum process as a fixed map on the state space of a predefined system of interest. Such a map averages over the system's environment, which may retain some effect of its past interactions with the system and thus have a history-dependent influence on the system. Although the theory of non-Markovian quantum dynamics is currently an active area of research, a systematic characterization method based on a general representation of non-Markovian dynamics has been lacking. In this article we present a systematic method for experimentally characterizing the dynamics of open quantum systems. Our method, which we call quantum process identification (QPI), is based on a general theoretical framework which relates the (non-Markovian) evolution of a system over an extended period of time to a time-local (Markovian) process involving the system and an effective environment. In practical terms, QPI uses time-resolved tomographic measurements of a quantum system to construct a dynamical model with as many dynamical variables as are necessary to reproduce the evolution of the system. Through numerical simulations, we demonstrate that QPI can be used to characterize qubit operations with non-Markovian errors arising from realistic dynamics including control drift, coherent leakage, and coherent interaction with material impurities.

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Optimization of a solid-state electron spin qubit using gate set tomography

Cited by 81 publications

References 41 publications

Experimental quantum verification in the presence of temporally correlated noise

Experimental quantum verification in the presence of temporally correlated noise

Relations between single and repeated qubit gates: coherent error amplification for high-fidelity quantum-gate tomography

Quantum process identification: a method for characterizing non-markovian quantum dynamics

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