Article
Quantum Science & Technology
B. Bantysh, A. Yu Chernyavskiy, Yu Bogdanov
Summary: Recent advances in quantum computers and simulators are leading to the development of full-scale quantum computing devices. Quantum tomography is a critical milestone in debugging and assessing the efficiency of different methods in various conditions. Developing a general methodology and software for comparing quantum-state tomography methods provides estimates of relative efficiency and method-specific features.
QUANTUM INFORMATION PROCESSING
(2021)
Article
Multidisciplinary Sciences
Kirill Dubovitskii, Yuriy Makhlin
Summary: In randomized benchmarking of quantum logical gates, partial twirling is used for simplification, improved scalability, and increased accuracy and reliability. By analyzing such simplified, partial twirling, it is found that the measured decay of fidelity is a linear combination of exponentials with different decay rates, and the evolution with the sequence length is governed by an iteration matrix.
SCIENTIFIC REPORTS
(2022)
Article
Quantum Science & Technology
Luciano Pereira, Leonardo Zambrano, Aldo Delgado
Summary: In this paper, we introduce an inductive n-qubit pure-state estimation method based on projective measurements. The method has a favorable scaling in the number of qubits and is well suited for applications in noisy intermediate-scale quantum computers. It can also estimate the purity of mixed states.
NPJ QUANTUM INFORMATION
(2022)
Article
Quantum Science & Technology
J. Helsen, I Roth, E. Onorati, A. H. Werner, J. Eisert
Summary: In this work, a rigorous framework of randomized benchmarking is developed, which is general enough to encompass nearly all known protocols and novel extensions. Modern signal processing techniques are introduced to analyze the fitting problem, and scalable postprocessing techniques are introduced to isolate exponential decays. It is discussed how the decay rates in randomized benchmarking can be used to infer quality measures.
Article
Quantum Science & Technology
Jahan Claes, Eleanor Rieffel, Zhihui Wang
Summary: This paper extends the character RB method to explicitly treat non-multiplicity-free groups and derive various applications, including a rigorous version of subspace RB, a new leakage RB protocol, and a scalable RB protocol for the matchgate group. Compared to existing theories, this method provides a more accurate estimate of gate fidelity or applies to a more general group of gates. The potential and challenges of using non-multiplicity-free character RB to develop new classes of scalable RB protocols and methods of characterizing specific gates are also discussed.
Article
Physics, Multidisciplinary
B. Nikolov, E. Diamond-Hitchcock, J. Bass, N. L. R. Spong, J. D. Pritchard
Summary: Using randomized benchmarking, the researchers demonstrated high-fidelity single-qubit gates on a neutral atom array. They also proposed a low-loss, nondestructive, and stateselective readout method.
PHYSICAL REVIEW LETTERS
(2023)
Article
Quantum Science & Technology
Wen-Wu Liu, Chun-Ling Zhang, Ling Zhang
Summary: In this paper, a one-step scheme to generate a CNOT gate via transitionless quantum driving is proposed, which exhibits robustness against instability related to variation in experimental parameters and decoherence. The scheme can be extended to generate a Toffoli gate for large-scale quantum computers, and its implementation is greatly simplified by involving only a single step.
QUANTUM INFORMATION PROCESSING
(2021)
Article
Quantum Science & Technology
Senrui Chen, Wenjun Yu, Pei Zeng, Steven T. Flammia
Summary: The study presents an efficient and noise-resilient protocol for learning properties of quantum states, which can effectively characterize and mitigate noise interference in the shadow estimation scheme, suitable for current experimental conditions, with good sampling efficiency and noise resilience.
Article
Optics
Yang Wang, Barbara M. Terhal
Summary: We propose a scheme for preparing Dicke states using global control of N spin qubits, based on the standard phase estimation algorithm. The scheme involves collectively coupling the spins to an ancilla qubit via ZZ interaction for non-deterministic state preparation. Potential applications include magnetic sensing using electronic spins coupled to a superconducting flux qubit, with analysis of noise and limitations in the scheme.
Article
Multidisciplinary Sciences
J. Helsen, M. Ioannou, J. Kitzinger, E. Onorati, A. H. Werner, J. Eisert, I. Roth
Summary: With quantum computing devices becoming more complex, there is a need for tools that can provide precise diagnostic information about quantum operations. The authors propose a new approach that uses random gate sequences and native measurements followed by classical post-processing to estimate various gate set properties. They also discuss applications for optimizing quantum gates and diagnosing cross-talk. This research is important for the development and improvement of quantum computing devices.
NATURE COMMUNICATIONS
(2023)
Article
Physics, Multidisciplinary
Yong Siah Teo, Seongwook Shin, Hyunseok Jeong, Yosep Kim, Yoon-Ho Kim, Gleb Struchalin, Egor Kovlakov, Stanislav S. Straupe, Sergei P. Kulik, Gerd Leuchs, Luis L. Sanchez-Soto
Summary: In this study, convolutional neural networks are trained to predict the completeness of information in quantum measurements, accelerating the characterization of quantum states. Experimental results show that trained networks can significantly reduce certification time and improve the computation yield of large-scale quantum processors.
NEW JOURNAL OF PHYSICS
(2021)
Article
Quantum Science & Technology
Akshay Gaikwad, Arvind, Kavita Dorai
Summary: In this study, the compressed sensing (CS) algorithm and a heavily reduced data set were used to perform true quantum process tomography on an NMR quantum processor. The CS algorithm demonstrated significantly better performance in the Pauli-error basis for estimating process matrices corresponding to various quantum gates.
QUANTUM INFORMATION PROCESSING
(2022)
Article
Physics, Multidisciplinary
Archismita Dalal, Amara Katabarwa
Summary: A universal fault-tolerant quantum computer is currently unavailable, but the development of near-term quantum algorithms like robust amplitude estimation (RAE) can optimize the performance of noisy intermediate-scale quantum (NISQ) computers and early fault tolerant (EFT) quantum computers. The lack of realistic error models has been a challenge for RAE, but we solve this by tailoring device noise using randomized compiling to generate an effective noise model that closely simulates the impact of device noise on RAE. By conducting noisy simulations, we demonstrate that our noise-tailored RAE algorithm can achieve improvements in bias and precision, even showing an advantage over standard estimation techniques on IBM's quantum computer ibmq_belem.
NEW JOURNAL OF PHYSICS
(2023)
Article
Optics
Yong-Jian Chen, Jin-Wei Gao, Jin-Xuan Han, Zhong-Hui Yuan, Ruo-Qi Li, Yong-Yuan Jiang, Jie Song
Summary: This study investigates the use of orbital angular momentum (OAM) to enhance phase estimation in Mach-Zehnder interferometers by employing non-Gaussian states as input resources in the presence of noise. The results show that non-Gaussian states, especially the photon-subtraction-then-addition state, exhibit the best sensitivity to symmetric noise. Additionally, higher order Bose operators of non-Gaussian states provide better sensitivity to symmetric noise. OAM can mitigate the deterioration of noise, enabling estimation of small phase shifts. It enhances the resolution and sensitivity of all input states and mitigates the deterioration caused by photon loss. Promising results are obtained even under significant photon loss, suggesting the potential for enhancing the sensitivity and robustness of quantum metrology.
Article
Physics, Multidisciplinary
Markus Rambach, Mahdi Qaryan, Michael Kewming, Christopher Ferrie, Andrew G. White, Jacquiline Romero
Summary: Self-guided tomography is demonstrated to be a practical, efficient, and robust technique for measuring higher-dimensional quantum states with high fidelities. The technique shows excellent performance for both pure and mixed states, achieving record high fidelities. It also exhibits robustness against various sources of experimental noise.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Erik Nielsen, Kenneth Rudinger, Timothy Proctor, Kevin Young, Robin Blume-Kohout
Summary: The technique presented in the study iteratively tests a nested sequence of models to find a good error model for a quantum processor, while keeping track of the best-fit model and its wildcard error at each step. The characterization of a processor is constituted by each best-fit model and a quantification of its unmodeled error. Moreover, the technique allows for comparison of quantum processor models with experimental data and among themselves.
NEW JOURNAL OF PHYSICS
(2021)
Article
Multidisciplinary Sciences
Mateusz T. Madzik, Serwan Asaad, Akram Youssry, Benjamin Joecker, Kenneth M. Rudinger, Erik Nielsen, Kevin C. Young, Timothy J. Proctor, Andrew D. Baczewski, Arne Laucht, Vivien Schmitt, Fay E. Hudson, Kohei M. Itoh, Alexander M. Jakob, Brett C. Johnson, David N. Jamieson, Andrew S. Dzurak, Christopher Ferrie, Robin Blume-Kohout, Andrea Morello
Summary: This study demonstrates universal quantum logic operations using nuclear spins in a silicon nanoelectronic device, achieving high-fidelity entangled states. The precise characterization of quantum operations shows that nuclear spins are approaching the performance required for fault-tolerant quantum processors. Additionally, the entanglement between nuclear spins and electron spins is also demonstrated. The results establish a viable route for scalable quantum information processing using donor nuclear and electron spins.
Article
Physics, Multidisciplinary
Timothy Proctor, Kenneth Rudinger, Kevin Young, Erik Nielsen, Robin Blume-Kohout
Summary: Quantum computers exhibit considerable performance variations across different architectures, limited by hardware errors which make accurately predicting their capabilities difficult. Current benchmarks lack flexibility, but scalable benchmarks using circuit mirroring techniques can be constructed, revealing that standard error metrics are poor predictors of program success on hardware, and processors differ widely in sensitivity to program structure.
Article
Physics, Applied
Kenneth Rudinger, Guilhem J. Ribeill, Luke C. G. Govia, Matthew Ware, Erik Nielsen, Kevin Young, Thomas A. Ohki, Robin Blume-Kohout, Timothy Proctor
Summary: Midcircuit measurements are an important primitive in quantum computing, especially for quantum error correction. In this study, we used quantum instrument linear gate set tomography (QILGST) technique to characterize dispersive measurements on a superconducting Transmon qubit and investigate the impact of residual cavity photon population on measurement error.
PHYSICAL REVIEW APPLIED
(2022)
Article
Physics, Multidisciplinary
Timothy Proctor, Stefan Seritan, Kenneth Rudinger, Erik Nielsen, Robin Blume-Kohout, Kevin Young
Summary: In this study, a simple and customizable class of circuits called randomized mirror circuits is shown to enable scalable, robust, and flexible randomized benchmarking of Clifford gates. Through simulations and experiments, the feasibility and scalability of the technique are demonstrated, and its capability of detecting and quantifying crosstalk errors in many-qubit circuits is validated.
PHYSICAL REVIEW LETTERS
(2022)
Article
Quantum Science & Technology
Akel Hashim, Stefan Seritan, Timothy Proctor, Kenneth Rudinger, Noah Goss, Ravi K. Naik, John Mark Kreikebaum, David I. Santiago, Irfan Siddiqi
Summary: It is found that under randomized compiling (RC), the errors of quantum gates can be accurately described by a stochastic Pauli noise model without coherent errors, and spatially correlated coherent errors and non-Markovian errors are strongly suppressed. The average and worst-case error rates are equal for randomly compiled gates, and the maximum worst-case error for the gate set is measured to be 0.0197(3) using gate set tomography.
NPJ QUANTUM INFORMATION
(2023)
Article
Quantum Science & Technology
Robin Blume-Kohout, Marcus P. da Silva, Erik Nielsen, Timothy Proctor, Kenneth Rudinger, Mohan Sarovar, Kevin Young
Summary: This study presents a method for modeling errors in quantum logic gates, by transforming the process matrix of a gate into a more useful error generator. A variety of reduced models for gate errors can be built by combining elementary error generators.
