Article
Automation & Control Systems
Wonjun Shin, Kyung Kyu Min, Jong-Ho Bae, Jaehyeon Kim, Ryun-Han Koo, Dongseok Kwon, Jae-Joon Kim, Daewoong Kwon, Jong-Ho Lee
Summary: In recent years, the development of neuromorphic computing has faced the limitations of von Neumann architecture. Therefore, there is a growing demand for high-performance synaptic devices that possess high switching speeds, low power consumption, and multilevel conductance. Among various synaptic devices, ferroelectric tunnel junctions (FTJs) have emerged as promising candidates. While previous studies have focused on improving the reliability of FTJs to enhance synaptic behavior, the low-frequency noise (LFN) of FTJs and its impact on the learning accuracy in neuromorphic computing have not been thoroughly investigated. This study explores the LFN characteristics of FTJs fabricated on n- and p-type Si and evaluates the impact of 1/f noise on the learning accuracy of convolutional neural networks (CNNs). The results demonstrate that FTJs on p-type Si exhibit significantly lower 1/f noise than those on n-type Si. Consequently, the FTJs on p-type Si achieve a significantly higher learning accuracy (86.26%) compared to those on n-type Si (78.70%) due to their low-noise properties. This study provides valuable insights into the LFN characteristics of FTJs and offers a potential solution to enhance the performance of synaptic devices by drastically reducing 1/f noise.
ADVANCED INTELLIGENT SYSTEMS
(2023)
Article
Quantum Science & Technology
Simanraj Sadana, Lorenzo Maccone, Urbasi Sinha
Summary: We use quantum computers to test the foundations of quantum mechanics through implementing quantum algorithms that serve as experimental tests for the theory's postulates. These algorithms can be used to test the efficacy of a quantum computer in obeying the postulates, assuming perfect hardware, or to test the hardware under the assumption that quantum theory is correct. This work demonstrates how algorithms can be utilized to examine the impact of different types of noise on experimental tests of the postulates, revealing how systematic errors affect the quantumness of the quantum computer.
QUANTUM INFORMATION PROCESSING
(2023)
Article
Engineering, Multidisciplinary
Lukasz Ciura, Jaroslaw Wrobel, Jacek Boguski, Jerzy Wrobel
Summary: This article demonstrates the use of the coherence function to analyze 1/f noise sources in a planar semiconductor structure with multiple electrical contacts. The study includes noise and coherence function measurements, the development of a 1/f noise model for the sample, theoretical calculations of the coherence function, and a comparison of theoretical and experimental values. The results show that the model, which assumes no 1/f noise from the bulk semiconductor and only 1/f noise from contacts, can effectively explain the experimental measurements of coherence. This method provides a straightforward interpretation and avoids the need for complex model parameters, unlike models based solely on power spectral density.
Article
Optics
J. Avron, Ofer Casper, Ilan Rozen
Summary: Distributed quantum computing can reduce noise and still exhibit quantum advantage in certain algorithms. However, some algorithms may have higher complexity in a distributed environment.
Article
Materials Science, Multidisciplinary
S. Sruthi, Deepa S. Narang, Prasad Vishnubhotla, Arnab Bera, Sk Kalimuddin, Kenji Watanabe, Takashi Taniguchi, Mintu Mondal, Aveek Bid
Summary: In this paper, we investigate the resistance fluctuations near the Lifshitz transition in WTe2 devices and identify the Lifshitz transition from electrical and thermal transport studies. Our study reveals the effect of interband scattering on the physics of Weyl semimetals through band structure analysis and electrical noise measurements.
Article
Multidisciplinary Sciences
Ali Shaib, Mohamad Hussein Naim, Mohammed E. Fouda, Rouwaida Kanj, Fadi Kurdahi
Summary: Quantum computers have the ability to solve problems that are beyond the capabilities of current machines, but handling noise is necessary. To address this, several protocols for efficient and accurate quantum noise profiling and mitigation have been proposed. In this study, a novel protocol is proposed to estimate the average output of a noisy quantum device efficiently, which can be used for quantum noise mitigation. The protocol approximates the average behavior of a multi-qubit system as a specific form of a Pauli Channel and uses Clifford gates to estimate the average output for circuits of different depths. The characterized Pauli channel error rates, as well as state preparation and measurement errors, are then used to construct the outputs for different depths, eliminating the need for large simulations and enabling efficient mitigation. The proposed protocol demonstrates improved accuracy with efficient noise characterization, showing up to 88% and 69% improvement compared to unmitigated and pure measurement error mitigation approaches, respectively.
SCIENTIFIC REPORTS
(2023)
Article
Multidisciplinary Sciences
Audrey Chu, Charlie Greboval, Yoann Prado, Hicham Majjad, Christophe Delerue, Jean-Francois Dayen, Gregory Vincent, Emmanuel Lhuillier
Summary: Narrow band gap nanocrystals provide an interesting platform for low-cost infrared sensors. A nanotrench device geometry designed using optical lithography demonstrates high responsivity and fast time response for short-wave infrared detection.
NATURE COMMUNICATIONS
(2021)
Article
Physics, Applied
Ziwen Huang, Xinyuan You, Ugur Alyanak, Alexander Romanenko, Anna Grassellino, Shaojiang Zhu
Summary: Although the Gaussian noise assumption is widely used in studying qubit decoherence, non-Gaussian noise sources have been found in many qubits. This study investigates qubit dephasing caused by non-Gaussian fluctuators and predicts a unique symmetry-breaking effect. The study also proposes a method to enhance coherence time by suppressing the second-order derivative of the qubit frequency using Floquet engineering.
PHYSICAL REVIEW APPLIED
(2022)
Article
Quantum Science & Technology
M. Carroll, S. Rosenblatt, P. Jurcevic, I Lauer, A. Kandala
Summary: Superconducting qubits, as a leading candidate for quantum computing, exhibit fluctuations in their energy relaxation times (T-1), which can cause instabilities in device performance. This study introduces a technique to probe the spectral and temporal dynamics of T-1 and discovers strong correlations between the mean T-1 and a snapshot of T-1 over a specific frequency range, offering a promising approach for rapid T-1 characterization.
NPJ QUANTUM INFORMATION
(2022)
Article
Optics
Kirill A. Kazakov
Summary: Quantum indeterminacy sets a lower bound on the power spectrum of voltage fluctuations, with a low-frequency asymptotic similar to 1/f and a modified behavior of 1/f^gamma due to charge-carrier-phonon interaction. The voltage variance grows with time as t(gamma-1), and the power spectrum remains well defined and finite for gamma < 2.
Article
Physics, Multidisciplinary
Anthony Kiely
Summary: All quantum systems are affected by noise and imperfections, which are crucial for the progress towards fully functional quantum devices. This perspective focuses on noise in quantum systems modelled by dynamic stochastic parameters in the Hamiltonian. The study outlines exact evolution equations and an approximate evolution equation for common noise types and their connections.
Article
Engineering, Electrical & Electronic
Yatao Peng, Andrea Ruffino, Edoardo Charbon
Summary: This study presents a cryogenic broadband low noise amplifier (LNA) for quantum applications based on a standard 40-nm CMOS technology, achieving broadband input matching impedance and low noise figure, while demonstrating sub-1 dB noise figure at 4.2 K temperature.
IEEE JOURNAL OF SOLID-STATE CIRCUITS
(2021)
Article
Physics, Multidisciplinary
Ferdinand Grueneis
Summary: Voss and Clarke observed thermal 1/f noise in samples in thermal equilibrium, which they attributed to spatially correlated temperature fluctuations and intermittent generation-recombination (g-r) pulses. They found no need to introduce other factors to explain 1/f noise.
PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS
(2022)
Article
Optics
Maria Hita-Perez, Pedro A. Orellana, Juan Jose Garcia-Ripoll, Manuel Pino
Summary: The study analyzes the coupling between heavy fluxonium without external flux and other systems and finds that when coupled to an extended system supporting a continuum of modes, the fluxonium can form a long-lived state. In the absence of noise, coupling the fluxonium to a superconducting waveguide can result in lifetimes on the order of seconds for the bound states in the continuum (BIC), even though typical device frequencies are in the gigahertz range. The presence of decoherence sources, such as finite temperature and 1/f flux noise, can affect the BIC decay times in realistic experiments.
Article
Physics, Applied
J. S. Rojas-Arias, A. Noiri, P. Stano, T. Nakajima, J. Yoneda, K. Takeda, T. Kobayashi, A. Sammak, G. Scappucci, D. Loss, S. Tarucha
Summary: In this study, we detected correlations in qubit-energy fluctuations of non-neighboring qubits in isotopically purified Si/Si-Ge quantum dots. The correlation coefficient reached 10% for a next-nearest-neighbor qubit-pair separated by 200 nm at low frequencies where the noise is strongest. We also found correlations with the charge-sensor signal reaching up to 70%, proving the electrical origin of the observed noise. A simple theoretical model accurately reproduced the measurements and predicted a polynomial decay of correlations with interqubit distance. These results quantify the long-range correlations of noise in quantum-dot spin-qubit arrays, which are essential for scalability and fault tolerance.
PHYSICAL REVIEW APPLIED
(2023)
Article
Quantum Science & Technology
Regina Finsterhoelzl, Guido Burkard
Summary: We evaluate the performance of small error-correcting codes tailored to different hardware platforms, taking into account hardware-specific errors and connectivity. We investigate the dependence of logical error rate on platform features and benchmark our predictions with experimental results. The results show that the quasi-linear layout of superconducting devices is advantageous for small codes, while the central-spin connectivity of color centers enables lower error rates for codes involving multi-qubit controlled operations.
QUANTUM SCIENCE AND TECHNOLOGY
(2023)
Review
Physics, Multidisciplinary
Guido Burkard, Thaddeus D. Ladd, Andrew Pan, John M. Nichol, Jason R. Petta
Summary: The spin degree of freedom of an electron or a nucleus is a basic property that provides a natural two-level system for quantum information processing. Semiconductor spin qubits have made significant advancements in terms of quantum state preparation, coherent control, and measurement. These qubits have the potential for scalable solid-state quantum information processing, thanks to their small size, high density, long coherence times, and existing industrial infrastructure.
REVIEWS OF MODERN PHYSICS
(2023)
Article
Quantum Science & Technology
Violeta N. N. Ivanova-Rohling, Niklas Rohling, Guido Burkard
Summary: Quantum state tomography is an essential tool for evaluating and validating quantum processors. In ideal scenarios, optimal measurement sets for tomography can be analytically determined, but in other cases, numerical approximation is needed. This study introduces a customized efficient tomography framework to find the optimal measurement set in the presence of noisy quantum gates. The results show that using entangling gates improves the accuracy of tomography reconstruction at realistic noise levels.
EPJ QUANTUM TECHNOLOGY
(2023)
Article
Optics
Jannis Ruh, Regina Finsterhoelzl, Guido Burkard
Summary: The paper presents a quantum algorithm for digital quantum simulations of the BCS model on a quantum register with a star-shaped connectivity map. The translation of the problem onto the quantum hardware and implementation using native interactions between qubits are discussed, along with the circuit complexity. The algorithm is used to simulate the dynamics of the BCS model and is studied using classical simulations.
Article
Optics
Philipp M. Mutter, Guido Burkard
Summary: We develop a theory to describe the transient transmission through noisy qubit-resonator systems, where quadratic interactions are present in superconducting and nanomechanical resonators coupled to solid-state qubits. By generalizing the quantum Langevin equations, we find that only linear and quadratic couplings allow for an analytical treatment using standard input-output theory. Focusing on quadratic couplings and arbitrary initial qubit coherences, we demonstrate that noise characteristics can be extracted from input-output measurements by analyzing the averaged fluctuations in transmission probability and phase. Our results extend the field of transmission-based noise spectroscopy and have immediate practical applications.
Article
Materials Science, Multidisciplinary
Balazs Gulacsi, Guido Burkard
Summary: We describe temporally correlated noise processes that influence the idle evolution of a superconducting transmon qubit. Based on quantum circuit theory, we model the composite qubit-environment system and derive a circuit Hamiltonian for transverse noise affecting the qubit. Using the time-convolutionless projection operator method, we construct a time-local master equation that exhibits eternally non-Markovian dynamics. By expressing the solution of the master equation in the Kraus representation, we identify two crucial non-Markovian phenomena: periodic revivals of coherence and the appearance of additional frequencies far from the qubit frequency.
Article
Optics
Joris Kattemoelle, Guido Burkard
Summary: The quantum approximate optimization algorithm (QAOA) has the potential to provide quantum advantage on noisy intermediate-scale quantum (NISQ) devices. Recent experimental results show that the errors impacting NISQ devices are significantly correlated. A model for spatially and temporally correlated errors based on classical environmental fluctuators is introduced. The study finds evidence that the performance of QAOA improves as the correlation time or correlation length of the noise increases at fixed local error probabilities, suggesting that noise correlations need not be detrimental for NISQ algorithms like QAOA.
Article
Materials Science, Multidisciplinary
Florian Ginzel, Guido Burkard
Summary: Both quantum transport measurements in the Pauli blockade regime and microwave cavity transmission measurements are important tools for spin-qubit readout and characterization. A theoretical framework is derived to investigate how a double quantum dot interacts with a coupled microwave resonator while the current through the dot is rectified by Pauli blockade. The output field of the resonator can be used to infer the leakage current and obtain insight into the blockade mechanisms, providing detailed knowledge about the microscopic environment of the dot.
Article
Materials Science, Multidisciplinary
Jonas Mielke, Guido Burkard
Summary: Nuclear spins have long coherence times, but isolating them from the environment for controlling nuclear spin qubits is challenging. Strong coupling between an electron spin and microwave resonator photons, as well as microwave resonator mediated coupling between two electron spins, has been reported. Inspired by these findings, we theoretically investigate the interaction of a microwave resonator with a hybrid quantum dot-donor (QDD) system. By driving the QDD system, we can compensate the frequency mismatch and enable effective nuclear spin-photon coupling. Coupling the nuclear spins of two distant QDD systems to the microwave resonator allows the implementation of a resonator-mediated nuclear spin two-qubit iSWAP gate with a gate fidelity approaching 90%.
Article
Physics, Multidisciplinary
T. L. M. Guedes, I Vakulchyk, D. V. Seletskiy, A. Leitenstorfer, A. S. Moskalenko, Guido Burkard
Summary: The influence of measurement back action on electro-optic sampling of electromagnetic quantum fluctuations is investigated. Based on a cascaded treatment of the nonlinear interaction between a near-infrared coherent probe and the mid-infrared vacuum, we account for the generated electric-field contributions that lead to detectable back action. The setup parameters at which back action starts to considerably contaminate the measured noise profiles are determined. We find that back action starts to detrimentally affect the signal once the fluctuations due to the coupling to the mid-infrared vacuum become comparable to the base shot noise. Due to the vacuum fluctuations entering at the beam splitter, the shot noise of two incoming probe pulses in different channels is uncorrelated. Therefore, even when the base shot noise dominates the output of the experiment, it does not contribute to the correlation signal itself. However, we find that further contributions due to nonlinear shot-noise enhancement are still present. Ultimately, a regime in which electro-optic sampling of quantum fields can be considered as effectively back-action free is found.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Optics
Philipp M. Mutter, Guido Burkard
Summary: Noise-induced decoherence is a major threat to large-scale quantum computation. In order to assess the noise affecting a qubit, we consider dynamical noise in the system description beyond the standard steady-state solution of qubit-coupled cavity transmission in input-output theory. By solving the quantum Langevin equations exactly for a noise-free system and treating the noise as a perturbation, we find that the corrections in the long-time limit can be expressed as convolutions of the noise power spectral density with an integration kernel dependent on external control parameters. Using the convolution theorem, we invert the corrections to obtain relations for the noise spectral density as integrals over measurable quantities. Furthermore, we accurately handle the noise in the dispersive regime and again observe that noise characteristics are present in long-time transmission in convolutions involving the power spectral density.
Article
Materials Science, Multidisciplinary
Stephen R. McMillan, Guido Burkard
Summary: A critical element for scalable quantum processors is the nonlocal coupling between nodes. Recent research has shown that spin-based qubits in double quantum dot architectures can exhibit spin-spin interactions via the exchange of photons. This study proposes a framework for a resonant direct-CNOT operation between nonlocal single-spin qubits.
Article
Physics, Multidisciplinary
Benedikt Tissot, Michael Trupke, Philipp Koller, Thomas Astner, Guido Burkard
Summary: Transition metal defects in silicon carbide show promise as a platform for quantum technology applications. Researchers have developed a driven, dissipative protocol to polarize nuclear spins, enabling the use of established methods for initializing and storing quantum states. This study represents the first step towards an all-optically controlled integrated platform for quantum technology with transition metal defects in SiC.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Optics
Emanuel Hubenschmid, Thiago L. M. Guedes, Guido Burkard
Summary: A multichannel quantum electro-optic sampling method is proposed for simultaneous measurements of different field quadratures and tuning interaction strengths. The probability distribution of the electro-optic signal outcomes is related to the indirectly measured MIR state. Consecutive measurements of (X) over cap and (Y) over cap quadratures can outperform eight-port homodyne detection.
Article
Materials Science, Multidisciplinary
Amin Hosseinkhani, Guido Burkard
Summary: In this study, we developed a theory for the relaxation of single-electron silicon spin qubits in the presence of a magnetic field gradient. We successfully reproduced experimental measurements using our theoretical modeling, showing that the presence of a gradient field can modify the spin-mixing mechanisms and the EDSR Rabi frequency of a silicon spin qubit. The effect strongly depends on the details of the interface roughness.
