Stabilizing and improving qubit coherence by engineering noise spectrum
of two-level systems
- URL: http://arxiv.org/abs/2206.10669v2
- Date: Tue, 11 Oct 2022 18:39:35 GMT
- Title: Stabilizing and improving qubit coherence by engineering noise spectrum
of two-level systems
- Authors: Xinyuan You, Ziwen Huang, Ugur Alyanak, Alexander Romanenko, Anna
Grassellino, and Shaojiang Zhu
- Abstract summary: Superconducting circuits are a leading platform for quantum computing.
Charge fluctuators inside amorphous oxide layers contribute to both low-frequency $1/f$ charge noise and high-frequency dielectric loss.
We propose to mitigate those harmful effects by engineering the relevant TLS noise spectral densities.
- Score: 52.77024349608834
- License: http://creativecommons.org/licenses/by/4.0/
- Abstract: Superconducting circuits are a leading platform for quantum computing.
However, their coherence times are still limited and exhibit temporal
fluctuations. Those phenomena are often attributed to the coupling between
qubits and material defects that can be well described as an ensemble of
two-level systems (TLSs). Among them, charge fluctuators inside amorphous oxide
layers contribute to both low-frequency $1/f$ charge noise and high-frequency
dielectric loss, causing fast qubit dephasing and relaxation. Moreover,
spectral diffusion from mutual TLS interactions varies the noise amplitude over
time, fluctuating the qubit lifetime. Here, we propose to mitigate those
harmful effects by engineering the relevant TLS noise spectral densities.
Specifically, our protocols smooth the high-frequency noise spectrum and
suppress the low-frequency noise amplitude via depolarizing and dephasing the
TLSs, respectively. As a result, we predict a drastic stabilization in qubit
lifetime and an increase in qubit pure dephasing time. Our detailed analysis of
feasible experimental implementations shows that the improvement is not
compromised by spurious coupling from the applied noise to the qubit.
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