Multi-level charge fluctuations in a Si/SiGe double quantum dot device

• URL: http://arxiv.org/abs/2601.08088v1
• Date: Tue, 13 Jan 2026 00:06:26 GMT
• Title: Multi-level charge fluctuations in a Si/SiGe double quantum dot device
• Authors: Dylan Albrecht, Feiyang Ye, N. Tobias Jacobson, John M. Nichol,
• Abstract summary: We measure multi-level charge fluctuations present in a Si/SiGe double quantum dot device over a range of device operating voltages and temperatures.<n>By tracking fluctuator transition rates, biases, and weights over a range of different device configurations, we estimate gate voltage and conductivity sensitivity.
• Score: 1.212038449348389
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Discrete charge fluctuations, routinely observed in semiconductor quantum dot devices, may contribute significantly to device drift and errors resulting from qubit miscalibration. Understanding the nature and origins of these discrete charge fluctuations may provide insights into material improvements or means of mitigating charge noise in semiconductor quantum dot devices. In this work, we measure multi-level charge fluctuations present in a Si/SiGe double quantum dot device over a range of device operating voltages and temperatures. To characterize the parameter-dependent dynamics of the underlying fluctuating degrees of freedom, we perform a detailed analysis of the measured noise timeseries. We perform algorithmically assisted drift detection and change point detection to detrend the data and remove a slow fluctuator component, as a preprocessing step. We perform model comparison on the post-processed time series between different $n$-level fluctuator ($n$LF) factorial hidden Markov models (FHMMs), finding that although at most sweep values the independent pair of 2LFs model would be preferred, in a particular region of voltage space the 4LF model outperforms the other models, indicating a conditional rate dependence between the two fluctuators. By tracking fluctuator transition rates, biases, and weights over a range of different device configurations, we estimate gate voltage and conductivity sensitivity. In particular, we fit a phenomenological, detailed balance model to the extracted independent 2LFs rate data, yielding lever arm estimates in the range of $-2 μ$eV/mV up to $4 μ$eV/mV between the two 2LFs and nearby gate electrodes. We expect that these characterization results may aid in subsequent spatial triangulation of the charge fluctuators.

Related papers

• Towards autonomous time-calibration of large quantum-dot devices: Detection, real-time feedback, and noise spectroscopy [0.0]
  We introduce a method that uses the full network of charge-transition lines in repeatedly acquired double-quantum-dot charge stability diagrams.<n>We detect voltage drifts, identify abrupt charge reconfigurations, and apply compensating updates to maintain stable operating conditions.<n>These capabilities form the basis of a scalable, autonomous calibration and characterization module for QD-based quantum processors.
  arXiv  Detail & Related papers  (2025-12-31T14:41:39Z)
• Design and Optimization of Spin Dynamics in Ge Quantum Dots: g-Factor Modulation, Dephasing Sweet Spots, and Phonon-Induced Relaxation [0.0]
  We present a three-dimensional study of gate-defined quantum dot hole spin qubits in strained Si$_0.2$Ge$_0.8$/Ge heterostructures.<n>We quantify the impact of device size and gate bias on wavefunction localization, electric-field-induced g-factor modulation, and identify "sweet spots" in vertical electric field where g-factor sensitivity to charge noise is minimized.
  arXiv  Detail & Related papers  (2025-09-12T22:39:03Z)
• Dissipative quantum phase transitions monitored by current fluctuations [0.0]
  Dissipative phase transitions (DPT) are defined by sudden changes in the physical properties of nonequilibrium open quantum systems.<n>Here, we consider the $textitoutput current$, defined as the average total quantum jumps per unit time between the open quantum system and the environment.<n>We propose that output current fluctuations, and in particular their dynamical correlations, their power spectrum, and their characteristic timescale can provide valuable information about DPT.
  arXiv  Detail & Related papers  (2025-02-03T08:08:08Z)
• Characterization of individual charge fluctuators in Si/SiGe quantum dots [0.5340587140262308]
  We probe individual two-level fluctuators (TLFs) in Si/SiGe quantum dots through simple quantum-dot transport measurements.<n>We find that the TLF switching times depend sensitively on gate voltages, decrease with temperature, and depend on the current through a nearby quantum dot.
  arXiv  Detail & Related papers  (2024-01-25T22:19:19Z)
• Ancilla quantum measurements on interacting chains: Sensitivity of entanglement dynamics to the type and concentration of detectors [46.76612530830571]
  We consider a quantum many-body lattice system that is coupled to ancillary degrees of freedom (detectors'') We explore the dynamics of density and of entanglement entropy in the chain, for various values of $rho_a$ and $M$.
  arXiv  Detail & Related papers  (2023-11-21T21:41:11Z)
• Two Anderson impurities coupled through a superconducting island: charge stability diagrams and double impurity qubit [0.0]
  We present a model of two Anderson impurities coupled to and through a superconducting island. We explore the effect of the model parameters in the subspaces with total even and odd occupancy. For total odd electron parity, we identify a device tuning, in which the splitting between the two lowest energy states is highly insensitive to changes of the chemical potentials.
  arXiv  Detail & Related papers  (2023-03-25T09:30:15Z)
• 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)
• Slow semiclassical dynamics of a two-dimensional Hubbard model in disorder-free potentials [77.34726150561087]
  We show that introduction of harmonic and spin-dependent linear potentials sufficiently validates fTWA for longer times. In particular, we focus on a finite two-dimensional system and show that at intermediate linear potential strength, the addition of a harmonic potential and spin dependence of the tilt, results in subdiffusive dynamics.
  arXiv  Detail & Related papers  (2022-10-03T16:51:25Z)
• Gate-based spin readout of hole quantum dots with site-dependent $g-$factors [101.23523361398418]
  We experimentally investigate a hole double quantum dot in silicon by carrying out spin readout with gate-based reflectometry. We show that characteristic features in the reflected phase signal arising from magneto-spectroscopy convey information on site-dependent $g-$factors in the two dots.
  arXiv  Detail & Related papers  (2022-06-27T09:07:20Z)
• Photoinduced prethermal order parameter dynamics in the two-dimensional large-$N$ Hubbard-Heisenberg model [77.34726150561087]
  We study the microscopic dynamics of competing ordered phases in a two-dimensional correlated electron model. We simulate the light-induced transition between two competing phases.
  arXiv  Detail & Related papers  (2022-05-13T13:13:31Z)
• Quantum correlations, entanglement spectrum and coherence of two-particle reduced density matrix in the Extended Hubbard Model [62.997667081978825]
  We study the ground state properties of the one-dimensional extended Hubbard model at half-filling. In particular, in the superconducting region, we obtain that the entanglement spectrum signals a transition between a dominant singlet (SS) to triplet (TS) pairing ordering in the system.
  arXiv  Detail & Related papers  (2021-10-29T21:02:24Z)
• Feedback-induced instabilities and dynamics in the Jaynes-Cummings model [62.997667081978825]
  We investigate the coherence and steady-state properties of the Jaynes-Cummings model subjected to time-delayed coherent feedback. The introduced feedback qualitatively modifies the dynamical response and steady-state quantum properties of the system.
  arXiv  Detail & Related papers  (2020-06-20T10:07:01Z)

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.