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Agarwal, Abhishek; Young, Donovan

doi:10.1103/physrevd.87.065029

Cited by 7 publications

(10 citation statements)

References 23 publications

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“…It is generally thought that 1/f noise in semiconductors results from a distribution of bistable charge states. Such fluctuators are regularly observed in various solid state platforms [24,[26][27][28][29][30][31][32][33][34][35][36]. A simple model for TLSs causing 1/f noise proposed by McWhorter [37] considers a distribution of TLSs, each of which switches between two states and contributes a Lorentzian power spectrum to the overall noise spectrum.…”

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confidence: 99%

Low-frequency charge noise in Si/SiGe quantum dots

et al. 2019

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Electron spins in silicon have long coherence times [1][2][3][4][5][6] and are a promising qubit platform [7,8]. However, electric field noise in semiconductors poses a challenge for most single-and multi-qubit operations in quantum-dot spin qubits [4,9,10]. Here, we investigate the dependence of lowfrequency charge noise spectra on temperature and aluminum-oxide gate dielectric thickness in Si/SiGe quantum dots with overlapping gates. We find that charge noise increases with aluminum oxide thickness. We also find strong dot-to-dot variations in the temperature dependence of the noise magnitude and spectrum. These findings suggest that each quantum dot experiences noise caused by a distinct ensemble of two-level systems, each of which has a non-uniform distribution of thermal activation energies. Taken together, our results suggest that charge noise in Si/SiGe quantum dots originates at least in part from a non-uniform distribution of two-level systems near the surface of the semiconductor.

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confidence: 99%

Low-frequency charge noise in Si/SiGe quantum dots

et al. 2019

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“…Here we resort to a variational method based on a partial polaron transformation [48,49]. The idea is that, when the impurity mass is large compared to the Tkachenko boson mass, the bosonic field can instantaneously adjust to the slow motion of the impurity.…”

Section: B Finite Impurity Massmentioning

confidence: 99%

Mobile impurities and orthogonality catastrophe in two-dimensional vortex lattices

Caracanhas

Pereira

2015

Phys. Rev. A

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We investigate the properties of a neutral impurity atom coupled with the Tkachenko modes of a two-dimensional vortex lattice in a Bose-Einstein condensate. In contrast with polarons in homogeneous condensates, the marginal impurity-boson interaction in the vortex lattice leads to infrared singularities in perturbation theory and to the breakdown of the quasiparticle picture in the low energy limit. These infrared singularities are interpreted in terms of a renormalization of the coupling constant, quasiparticle weight and effective impurity mass. The divergence of the effective mass in the low energy limit gives rise to a power law singularity in the impurity spectral function and provides an example of an emergent orthogonality catastrophe in a bosonic system.

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“…12 Such two-level fluctuators involve tunneling between two spatial configurations with nearly equal potential energy and are routinely observed in amorphous materials. [13][14][15][16] These fluctuators have been observed as spurious resonances in the spectrum of superconducting phase qubits, 17 and have been the subject of an extensive literature in the Josephson qubit community. [18][19][20][21][22] Similar two-level fluctuators consisting of a charge hopping between localized states have been observed in the environment of various other solid-state devices, including lateral gated heterostructures [23][24][25][26] and self-assembled quantum dots.…”

Section: Introductionmentioning

confidence: 99%

Microscopic models for charge-noise-induced dephasing of solid-state qubits

Beaudoin

Coish

2015

Phys. Rev. B

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Several experiments have shown qubit coherence decay of the form exp [−(t/T2) α ] due to environmental charge-noise fluctuations. We present a microscopic description for temperature dependences of the parameters T2 and α. Our description is appropriate to qubits in semiconductors interacting with spurious two-level charge fluctuators coupled to a thermal bath. We find distinct power-law dependences of T2 and α on temperature depending on the nature of the interaction of the fluctuators with the associated bath. We consider fluctuator dynamics induced by first-and second-order tunneling with a continuum of delocalized electron states. We also study one-and two-phonon processes for fluctuators in either GaAs or Si. These results can be used to identify dominant charge-dephasing mechanisms and suppress them.

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Deconstructing supersymmetricSmatrices inD≤2+1

Cited by 7 publications

References 23 publications

Low-frequency charge noise in Si/SiGe quantum dots

Low-frequency charge noise in Si/SiGe quantum dots

Mobile impurities and orthogonality catastrophe in two-dimensional vortex lattices

Microscopic models for charge-noise-induced dephasing of solid-state qubits

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