Characterizing low-frequency qubit noise

• URL: http://arxiv.org/abs/2207.01740v1
• Date: Mon, 4 Jul 2022 22:48:43 GMT
• Title: Characterizing low-frequency qubit noise
• Authors: Filip Wudarski, Yaxing Zhang, Alexander Korotkov, A. G. Petukhov, and M. I. Dykman
• Abstract summary: Fluctuations of the qubit frequencies are one of the major problems to overcome on the way to scalable quantum computers. The statistics of the fluctuations can be characterized by measuring the correlators of the outcomes of periodically repeated Ramsey measurements. This work suggests a method that allows describing qubit dynamics during repeated measurements in the presence of evolving noise.
• Score: 55.41644538483948
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: Fluctuations of the qubit frequencies are one of the major problems to overcome on the way to scalable quantum computers. Of particular importance are fluctuations with the correlation time that exceeds the decoherence time due to decay and dephasing by fast processes. The statistics of the fluctuations can be characterized by measuring the correlators of the outcomes of periodically repeated Ramsey measurements. This work suggests a method that allows describing qubit dynamics during repeated measurements in the presence of evolving noise. It made it possible, in particular, to evaluate the two-time correlator for the noise from two-level systems and obtain two- and three-time correlators for a Gaussian noise. The explicit expressions for the correlators are compared with simulations. A significant difference of the three-time correlators for the noise from two-level systems and for a Gaussian noise is demonstrated. Strong broadening of the distribution of the outcomes of Ramsey measurements, with a possible fine structure, is found for the data acquisition time comparable to the noise correlation time.

Related papers

• Purity benchmarking study of error coherence in a single Xmon qubit [0.0]
  We simultaneously measure the coherence noise budget across two different operational frequencies. Incoherent errors, which predominate in overall error rates, exhibit minimal frequency dependence. Coherent errors, although less prevalent, show significant sensitivity to operational frequency variations and telegraphic noise.
  arXiv  Detail & Related papers  (2024-07-10T18:01:04Z)
• Stochastic action for the entanglement of a noisy monitored two-qubit system [55.2480439325792]
  We study the effect of local unitary noise on the entanglement evolution of a two-qubit system subject to local monitoring and inter-qubit coupling. We construct a Hamiltonian by incorporating the noise into the Chantasri-Dressel-Jordan path integral and use it to identify the optimal entanglement dynamics. Numerical investigation of long-time steady-state entanglement reveals a non-monotonic relationship between concurrence and noise strength.
  arXiv  Detail & Related papers  (2024-03-13T11:14:10Z)
• Spatio-temporal correlations of noise in MOS spin qubits [0.2981781876202281]
  We show how to decompose signals into both frequency and time components to gain a deeper insight into the sources of noise in our systems. We apply the analysis to a long feedback experiment performed on a state-of-the-art two-qubit system in a pair of SiMOS quantum dots.
  arXiv  Detail & Related papers  (2023-09-21T23:45:14Z)
• Spatially correlated classical and quantum noise in driven qubits: The good, the bad, and the ugly [0.0]
  Correlated noise across multiple qubits poses a significant challenge for achieving scalable quantum processors. We study the dynamics of driven qubits under spatially correlated noise, including both Markovian and non-Markovian noise. In particular, we reveal that, in the quantum limit, pure dephasing noise induces a coherent long-range two-qubit Ising interaction that correlates distant qubits.
  arXiv  Detail & Related papers  (2023-08-06T08:34:49Z)
• Decoherence of a tunable capacitively shunted flux qubit [0.0]
  The measured relaxation at the qubit symmetry point is mainly due to intrinsic flux noise in the main qubit loop for qubit frequencies below $sim3textGHz$. The measured dephasing rate is primarily due to tunable intrinsic low-frequency flux noise in the two qubit loops. Our results are relevant for ongoing efforts toward building superconducting quantum annealers with increased coherence.
  arXiv  Detail & Related papers  (2023-07-26T05:22:05Z)
• Parameter estimation from an Ornstein-Uhlenbeck process with measurement noise [0.0]
  We present an algorithm that can effectively separate thermal noise with comparable performance to Hamilton Monte Carlo. We show that, with additional knowledge of the ratio between thermal and multiplicative noise, we can accurately distinguish between the two types of noise.
  arXiv  Detail & Related papers  (2023-05-22T21:28:57Z)
• Autonomous coherence protection of a two-level system in a fluctuating environment [68.8204255655161]
  We re-examine a scheme originally intended to remove the effects of static Doppler broadening from an ensemble of non-interacting two-level systems (qubits) We demonstrate that this scheme is far more powerful and can also protect a single (or even an ensemble) qubit's energy levels from noise which depends on both time and space.
  arXiv  Detail & Related papers  (2023-02-08T01:44:30Z)
• Stabilizing and improving qubit coherence by engineering noise spectrum of two-level systems [52.77024349608834]
  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.
  arXiv  Detail & Related papers  (2022-06-21T18:37:38Z)
• High-Order Qubit Dephasing at Sweet Spots by Non-Gaussian Fluctuators: Symmetry Breaking and Floquet Protection [55.41644538483948]
  We study the qubit dephasing caused by the non-Gaussian fluctuators. We predict a symmetry-breaking effect that is unique to the non-Gaussian noise.
  arXiv  Detail & Related papers  (2022-06-06T18:02:38Z)
• Learning Noise via Dynamical Decoupling of Entangled Qubits [49.38020717064383]
  Noise in entangled quantum systems is difficult to characterize due to many-body effects involving multiple degrees of freedom. We develop and apply multi-qubit dynamical decoupling sequences that characterize noise that occurs during two-qubit gates.
  arXiv  Detail & Related papers  (2022-01-26T20:22:38Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.