How to Enhance Dephasing Time in Superconducting Qubits

By Ł. Cywiński, R. Lutchyn, Cody P. Nave. 2007

435 citations recorded by the source corpus.

We theoretically investigate the influence of designed pulse sequences in restoring quantum coherence lost due to background noise in superconducting qubits. We consider both $1/f$ noise and random telegraph noise and show that the qubit coherence time can be substantially enhanced by carefully engineered pulse sequences. Conversely, the time dependence of qubit coherence under external pulse sequences could be used as a spectroscopic tool for extracting the noise mechanisms in superconducting qubits, i.e., by using Uhrig's pulse sequence [Phys. Rev. Lett. 98, 100504 (2007)], one can obtain information about moments of the spectral density of noise. We also study the effect of pulse sequences on the evolution of the qubit affected by a strongly coupled fluctuator and show that the non-Gaussian features in decoherence are suppressed by the application of pulses.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/5f5adaf53d905b114591b39026ad4ee474700e57

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Citations in the corpus

Noise spectroscopy through dynamical decoupling with a superconducting flux qubit (2011, methodology): “es square pulses, but is a reasonable approximation in our case. Alternatively to equation (21), one can deﬁne a function FN(ω,τ) = |yN(ω,τ)|2 that ﬁlters the phase noise, S(ω)/ω2, as in, e.g., Refs. [11,16,21,22,37]. The Ramsey free induction (N = 0) and the Hahn spin echo (N = 1) have weighting fu”
Dynamical decoupling for superconducting qubits: A performance survey (2022, background): “The idea is to find which DD sequence acts as an optimal filter function on the noise-spectral density of the bath while relaxing the constraint of uniform pulse intervals [51, 62–64].”
Sensitivity optimization for NV-diamond magnetometry (2019, methodology): “Here th NMR signal s measur d sing a modified XY8-k dynamic l decoupling sequence (8) and detect d using repetitive readout of the electroni spin state. jyie and jφin correspond t the electric and nuclear spin state , respectively.”
Dynamical decoupling and noise spectroscopy with a superconducting flux qubit (2011, background): “[11, 16, 21, 22, 37].”
Decoherence of ensembles of nitrogen-vacancy centers in diamond (2020, methodology): “where f(t) are step-like functions describing the periodic inversion of the NV spin for the pulse sequence under consideration [25, 56], and B(t) includes the random magnetic fields due to the spin bath surrounding the NV center.”
1 / f noise: Implications for solid-state quantum information (2013, methodology): “Referring to superconducting qubits, Cywinski et al. (2008) studied CMPG, UDD and CDD for 1/fα (0.5 ≤ α ≤ 1.5) Gaussian classical noise at pure dephasing with UV-cutoff ωc.”
Review of performance metrics of spin qubits in gated semiconducting nanostructures (2021, background): “[66], which derived log f (t) ∼ (t∕T2) as the envelope for decay under a generic dynamical-decoupling sequence assuming noise spectrum 1∕f .”