Noise spectroscopy through dynamical decoupling with a superconducting flux qubit

Bylander, Jonas; Gustavsson, Simon; Yan, Fei; Yoshihara, Fumiki; Harrabi, K.; Fitch, George; Cory, David G.; Nakamura, Y.; Tsai, Jaw Shen; Oliver, William

doi:10.1038/nphys1994

Cited by 727 publications

(903 citation statements)

References 38 publications

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“…We apply a spectral decomposition technique [21][22][23] to characterize the dynamics of the composite solid-state spin bath, consisting of both electronic spin (N) and nuclear spin ( 13 C) impurities. We study three different diamond samples with a wide range of NV densities and impurity spin concentrations (measuring both NV ensembles and single NV centres), and find unexpectedly long correlation times for the electronic spin baths in two diamond samples with natural abundance (1.1%) of 13 C nuclear spin impurities.…”

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confidence: 99%

Suppression of spin-bath dynamics for improved coherence of multi-spin-qubit systems

et al. 2012

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multi-qubit systems are crucial for the advancement and application of quantum science. such systems require maintaining long coherence times while increasing the number of qubits available for coherent manipulation. For solid-state spin systems, qubit coherence is closely related to fundamental questions of many-body spin dynamics. Here we apply a coherent spectroscopic technique to characterize the dynamics of the composite solid-state spin environment of nitrogen-vacancy colour centres in room temperature diamond. We identify a possible new mechanism in diamond for suppression of electronic spin-bath dynamics in the presence of a nuclear spin bath of sufficient concentration. This suppression enhances the efficacy of dynamical decoupling techniques, resulting in increased coherence times for multispin-qubit systems, thus paving the way for applications in quantum information, sensing and metrology.

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confidence: 99%

Suppression of spin-bath dynamics for improved coherence of multi-spin-qubit systems

et al. 2012

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“…In cases when both relaxation and dephasing exhibit exponential decay laws, their inverse times add to a decoherence rate T −1 2 = (2T 1 ) −1 + T −1 ϕ . While T 1 can now exceed 10 µs in several superconducting qubit modalities [1][2][3] , further improvements are required to comfortably exceed even the most lenient error correction thresholds. In general, energy relaxation is irreversible, such that further control-based improvements require resource-intensive multi-qubit quantum error-correction protocols.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopy of low-frequency noise and its temperature dependence in a superconducting qubit

et al. 2012

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We report a direct measurement of the low-frequency noise spectrum in a superconducting flux qubit. Our method uses the noise sensitivity of a free-induction Ramsey interference experiment, comprising free evolution in the presence of noise for a fixed period of time followed by single-shot qubit-state measurement. Repeating this procedure enables Fourier-transform noise spectroscopy with access to frequencies up to the achievable repetition rate, a regime relevant to dephasing in ensemble-averaged time-domain measurements such as Ramsey interferometry. Rotating the qubit's quantization axis allows us to measure two types of noise: effective flux noise and effective criticalcurrent or charge noise. For both noise sources, we observe that the very same 1/f -type power laws measured at considerably higher frequencies (0.2 − 20 MHz) are consistent with the noise in the 0.01 − 100-Hz range measured here. We find no evidence of temperature dependence of the noises over 65 − 200 mK, and also no evidence of time-domain correlations between the two noises. These methods and results are pertinent to the dephasing of all superconducting qubits.

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“…The DD technique is becoming an important tool for QIP [49,[54][55][56]59-67] as well as in spectroscopy [68][69][70][71] and imaging [72][73][74][75]. In most cases, the goal is to preserve a given input state, but it may also be combined with gate operations [76][77][78][79][80].…”

Section: Introductionmentioning

confidence: 99%

Robust dynamical decoupling

Souza

Álvarez

Suter

2012

Phil. Trans. R. Soc. A.

172

193

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Quantum computers, which process information encoded in quantum mechanical systems, hold the potential to solve some of the hardest computational problems. A substantial obstacle for the further development of quantum computers is the fact that the lifetime of quantum information is usually too short to allow practical computation. A promising method for increasing the lifetime, known as dynamical decoupling (DD), consists of applying a periodic series of inversion pulses to the quantum bits. In the present review, we give an overview of this technique and compare different pulse sequences proposed earlier. We show that pulse imperfections, which are always present in experimental implementations, limit the performance of DD. The loss of coherence due to the accumulation of pulse errors can even exceed the perturbation from the environment. This effect can be largely eliminated by a judicious design of pulses and sequences. The corresponding sequences are largely immune to pulse imperfections and provide an increase of the coherence time of the system by several orders of magnitude.

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Noise spectroscopy through dynamical decoupling with a superconducting flux qubit

Cited by 727 publications

References 38 publications

Suppression of spin-bath dynamics for improved coherence of multi-spin-qubit systems

Suppression of spin-bath dynamics for improved coherence of multi-spin-qubit systems

Spectroscopy of low-frequency noise and its temperature dependence in a superconducting qubit

Robust dynamical decoupling

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