Article
Optics
Fu-Quan Dou, Fang-Mei Yang
Summary: In this paper, an implementation scheme of a quantum battery (QB) based on a superconducting circuit is proposed. The QB consists of N coupled transmon qubits and a one-dimensional transmission line resonator. The Hamiltonian of the QB system is derived and its charging performance is investigated by considering three decay channels. It is found that the presence of decay channels suppresses the high oscillation of the energy storage process, leading to a stable and powerful QB.
Article
Multidisciplinary Sciences
T. Brown, E. Doucet, D. Riste, G. Ribeill, K. Cicak, J. Aumentado, R. Simmonds, L. Govia, A. Kamal, L. Ranzani
Summary: In this study, the authors achieved fast and high-fidelity Bell state stabilization in a qutrit-qubit system using a protocol based on parametric system-bath coupling. By creating a purely dissipative channel, they achieved trade-off-free Bell state stabilization in terms of steady-state fidelity and stabilization rate.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Multidisciplinary
Stefan Trandafir, Petr Lisonek, Adan Cabello
Summary: Magic sets of observables are fundamental tools for investigating the interface between classical and quantum physics. This study answers two open questions regarding magic sets and provides an efficient algorithm for determining if a hypergraph can accommodate a magic set.
PHYSICAL REVIEW LETTERS
(2022)
Article
Quantum Science & Technology
Johannes Weidenfeller, Lucia C. Valor, Julien Gacon, Caroline Tornow, Luciano Bello, Stefan Woerner, Daniel J. Egger
Summary: This article investigates swap strategies for mapping dense problems into different types of coupling maps, and finds that the required gate fidelity for dense problems is lower than expected based on entropic arguments. The author also introduces a methodology for reasoning about the execution time of QAOA, and demonstrates its application using a Qiskit Runtime program on cloud-based quantum computers. The study highlights obstacles to improving QAOA's competitiveness and provides insights into gate fidelity, gate speed, and the number of shots needed.
Article
Physics, Multidisciplinary
Kosuke Mizuno, Takaaki Takenaka, Imran Mahboob, Shiro Saito
Summary: In this study, the effect of various loss channels on the performance of logical gates on a bosonic qubit is investigated through numerical simulations. A gate error model is developed to predict experimentally achievable gate errors for bosonic qubits, providing insights into loss mechanisms and suggesting more efficient optimization algorithms to reduce gate errors.
NEW JOURNAL OF PHYSICS
(2023)
Review
Physics, Nuclear
Olivier Ezratty
Summary: This article describes the history and developments of superconducting qubit-based quantum computers, which are currently dominant in the industry. It showcases the diversity of technology options from an engineering viewpoint, explains the manufacturing process of superconducting qubit chipsets, and discusses challenges in driving qubits with classical electronics. It also explores methods to improve qubit fidelities and optimize their energy efficiency. Additionally, the article provides an overview of NISQ computers and their resource requirements for running potential use cases, particularly in quantum many-body physics simulations.
EUROPEAN PHYSICAL JOURNAL A
(2023)
Article
Physics, Multidisciplinary
Zhiling Wang, Zenghui Bao, Yukai Wu, Yan Li, Cheng Ma, Tianqi Cai, Yipu Song, Hongyi Zhang, Luming Duan
Summary: The article demonstrates how utilizing constructive interference between transmitted and reflected signals can optimize qubit state readout, leading to better state discrimination and improved qubit readout fidelity. This simple and convenient approach can be combined with other methods to further enhance qubit state readout.
CHINESE PHYSICS LETTERS
(2021)
Article
Optics
Qi-Ping Su, Yu Zhang, Chui-Ping Yang
Summary: This study proposes a one-step implementation of a multi-target qubit controlled-NOT gate, where a superconducting qubit controls multiple cat-state qubits simultaneously. The gate operation is simple, quick, and independent of the number of target qubits.
Article
Chemistry, Multidisciplinary
Xin-Xin Yang, Xiao-Yan Yang, Liang-Liang Guo, Lei Du, Peng Duan, Zhi-Long Jia, Hai-Ou Li, Guo-Ping Guo
Summary: One significant source of decoherence in superconducting circuits, known as two-level systems (TLSs), is found in amorphous oxide layers. These circuits can also be utilized as spectral and temporal TLS probes. Recent advancements in superconducting qubits allow for comprehensive investigations on the physics of TLSs. In this study, the tunable Xmon qubit decoherence time and resonance frequency were measured for over 3 days to study stochastic fluctuations. Analysis of time-domain Allan deviation and frequency-domain power spectral density indicates that two TLSs near resonance with the qubit are responsible for the fluctuations. The location of these two TLSs near the junctions was determined through extracted oscillation in T1 decay.
APPLIED SCIENCES-BASEL
(2023)
Article
Physics, Multidisciplinary
Shuanping Du, Zhaofang Bai
Summary: Strictly incoherent operations (SIO) are potential candidates for free operations in the resource theory of quantum coherence. The search for minimal parametrization with operational efficiency and a structural characterization of bistochastic SIOs using Pauli operators and Phase operator have been key focuses of research.Applications of these results include reconstructing quantum thermal averages via a quantum computer and coherence manipulation.
Article
Physics, Multidisciplinary
Wei Feng, Dexi Shao, Guo-Qiang Zhang, Qi-Ping Su, Jun-Xiang Zhang, Chui-Ping Yang
Summary: Motivated by recent realizations of 2D superconducting-qubit lattices, this study proposes a protocol to simulate the Hofstadter butterfly with synthetic gauge fields in superconducting circuits. By constructing a generalized Hofstadter model on zigzag lattices, a fractal energy spectrum similar to the original Hofstadter butterfly is achieved. The resonant frequencies of qubits are periodically modulated to engineer a synthetic gauge field, and a spectroscopic method is used to demonstrate the butterfly spectrum. Numerical simulations with realistic parameters confirm the presence of the butterfly spectrum. This proposal provides a promising approach for realizing the Hofstadter butterfly on the latest 2D superconducting-qubit lattices and will stimulate quantum simulation of novel properties induced by magnetic fields in superconducting circuits.
FRONTIERS OF PHYSICS
(2023)
Article
Physics, Multidisciplinary
Mohadese Forozesh, Ali Mortezapour, Alireza Nourmandipour
Summary: The study reveals that there are optimal modulation parameters for maintaining long-lasting qubit-photon entanglement and robust swapped entanglement. Additionally, the entropic uncertainty can be kept small for a long time with these optimal modulation parameters.
EUROPEAN PHYSICAL JOURNAL PLUS
(2021)
Article
Physics, Condensed Matter
Yuqian Dong, Qiang Liu, Jianhua Wang, Qingshi Li, Xiaoyan Yu, Wen Zheng, Yong Li, Dong Lan, Xinsheng Tan, Yang Yu
Summary: An experimental simulation of a two-qubit system was conducted using a four-level superconducting circuit, with implementation of designed microwave pulses for some two-qubit gates. The Shannon entropy of the simulated system was measured, confirming the log 2 uncertainty relation and the existence of hidden quantum correlations in the noncomposite single-qudit system.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2022)
Article
Optics
Klee Pollock, Ge Wang, Eric Chitambar
Summary: The paper investigates the entanglement of assistance in the simplest scenario of three qubits, finding that lossless decoupling may be possible under certain conditions. Different measures of entanglement can lead to different outcomes.
Article
Quantum Science & Technology
Aravind Plathanam Babu, Jani Tuorila, Tapio Ala-Nissila
Summary: Superconducting Josephson junction qubits are key in many applications, such as scalable quantum computers and thermal devices. Theoretical modeling typically uses the two-level approximation, but accurately capturing system dynamics requires considering higher excited states beyond this framework. This study explores the dynamics and control of a superconducting transmon, highlighting the impact of state leakage and the effectiveness of derivative removal adiabatic gates (DRAG) control in mitigating leakage errors.
NPJ QUANTUM INFORMATION
(2021)
Article
Physics, Multidisciplinary
Yury Belousov, Vladimir I. Man'ko, Agostino Migliore, Alessandro Sergi, Antonino Messina
Summary: This study investigates a system of two spins 1/2, revealing the notable symmetry properties of the corresponding Hamiltonian model and showing the characteristics of S-2. By appropriate mapping, it is possible to simulate the time evolution of a pseudo-qutrit, and investigate the dynamic similitude using two types of representation for the initial density matrix of the two spins.
Article
Optics
Andrey Yu Fedorov, Vladimir Man'ko
Summary: This passage discusses the superposition principle of a qubit, formulating it as a nonlinear addition rule of the mean values of spin projections onto three perpendicular directions. It also provides explicit expressions for the mean values that determine the superposition states, based on the mean values of two initial pure states of the qubit.
JOURNAL OF RUSSIAN LASER RESEARCH
(2022)
Article
Physics, Multidisciplinary
Julio A. Lopez-Saldivar, Margarita A. Man'ko, Vladimir I. Man'ko
Summary: In the framework of probability representation in quantum mechanics, we investigated a superposition of Gaussian states associated with the symmetries of a regular polygon. By obtaining the Wigner functions and tomographic probability distributions, we explicitly determined the density matrices of these states as sums of Gaussian terms. The obtained results exhibit nonclassical behavior and varied extrema for each state, with the number of critical points reflecting the order of the symmetry group defining the states.
Article
Physics, Multidisciplinary
M. A. Gavreev, A. S. Mastiukova, E. O. Kiktenko, A. K. Fedorov
Summary: In this work, we propose a machine learning method called 'learning by confusion' to detect entanglement breakdown in quantum states. We demonstrate its effectiveness for various types of entangled states and investigate its application in studying entanglement breakdown in noisy quantum devices. Overall, our approach provides a useful tool for understanding and characterizing entanglement properties.
NEW JOURNAL OF PHYSICS
(2022)
Article
Multidisciplinary Sciences
A. Antipov, E. O. Kiktenko, A. K. Fedorov
Summary: Efficient realization of quantum algorithms is a major challenge in practical quantum computing. We present a software package that implements various quantum gates and well-known quantum algorithms using the PennyLane library. Additionally, we have developed a technique for decomposing algorithms into native gates for trapped-ion quantum processors and derived the necessary coefficients for this decomposition. The templates in the package include all the required elements for the quantum part of Shor's algorithm and can be used for an arbitrary number of qubits.
Article
Geochemistry & Geophysics
S. M. Korotaev, N. M. Budnev, V. O. Serdyuk, E. O. Kiktenko, D. A. Orekhova
Summary: The vertical component of the electric field E-z in water column can effectively monitor sources excited by processes in the hydrosphere and geospheres-atmosphere and lithosphere. The deep-water experiment in Lake Baikal shows high accuracy in monitoring water transport, detection of GEC current, and recording of earthquake effects and precursors. The measurements of E-z and nonlocal correlations provide the possibility of forecasting random processes such as solar activity, hydrothermodynamic activity, and strong earthquakes.
IZVESTIYA-PHYSICS OF THE SOLID EARTH
(2022)
Article
Physics, Applied
Y. F. Zolotarev, I. A. Luchnikov, J. A. Lopez-Saldivar, A. K. Fedorov, E. O. Kiktenko
Summary: This article presents a continuous monitoring system for intermediate-scale quantum processors that can extract estimates of noisy native gate and read-out measurements without control. The results demonstrate that the system provides valuable information about the inherent noise of quantum emulators and processors without the need for additional algorithms.
PHYSICAL REVIEW APPLIED
(2023)
Article
Optics
Evgeniy O. Kiktenko
Summary: In this study, a formalism called time-bidirectional state formalism (TBSF) is presented, which unifies the standard quantum mechanical formalism with no postselection and the time-symmetrized two-state (density) vector formalism. It introduces the concept of a time-bidirectional state, which is equivalent to a joined state of two particles propagating in opposite time directions. The study derives outcome probabilities of generalized measurements, mean values, and weak values for a general time-bidirectional state, and shows how these expressions reduce to known ones in specific cases. Additionally, tomography protocols are developed for reconstructing unknown single-qubit time-bidirectional states.
Article
Optics
A. Antipov, E. O. Kiktenko, A. K. Fedorov
Summary: We present a class of neighboring-block stabilizer quantum error correction codes that can be implemented efficiently using a single ancilla and circular near-neighbor qubit connectivity. We propose an implementation for syndrome-measurement circuits for codes from the class and demonstrate its effectiveness using examples of three-qubit repetition code, Laflamme's five-qubit code, and Shor's nine-qubit code.
Article
Computer Science, Information Systems
Sergey V. Grebnev, Maxim A. Gavreev, Evgeniy O. Kiktenko, Anton P. Guglya, Albert R. Efimov, Aleksey K. Fedorov
Summary: In this passage, the author discusses the importance of quantum computing devices in solving the prime factorization problem and highlights the resource requirements of Shor's quantum factorization algorithm. Additionally, the author criticizes a new proposal for quantum factorization algorithm, claiming it lacks a systematic analysis of the classical part of the algorithm.
Article
Physics, Multidisciplinary
I. A. Luchnikov, E. O. Kiktenko, M. A. Gavreev, H. Ouerdane, S. N. Filippov, A. K. Fedorov
Summary: The article introduces a data-driven approach to analyzing the non-Markovian dynamics of open quantum systems, which can capture key characteristics of the system and reconstruct predictive models while denoising measured data.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Optics
Yu M. Belousov, N. N. Elkin, V. Man'ko, S. Revenko, I. A. Tarakanov, L. N. Tikhomirova
Summary: The tomographic representation for signal processing is applied in the study of living system signals. The use of a reference signal allows for the observation of tomogram transformations for functions described by f(t) and f(-t). The results show that this approach provides new opportunities for obtaining additional and useful information.
JOURNAL OF RUSSIAN LASER RESEARCH
(2022)
Article
Optics
A. S. Nikolaeva, E. O. Kiktenko, A. K. Fedorov
Summary: The problem of finding efficient decompositions of multiqubit gates is crucial in quantum computing. This paper proposes a decomposition scheme for a generalized N-qubit Toffoli gate, which is directly applicable to existing noisy intermediate-scale quantum devices.
Article
Optics
Peter Adam, Margarita A. Man'ko, Vladimir Man'ko
Summary: This article discusses even and odd coherent states in quantum mechanics and their probability representation. The formalism of quantizer and dequantizer operators is used to construct Wigner functions, and the relationship between Wigner functions and probability distributions is obtained through the Radon integral transform. The concept of entangled classical probability distributions is introduced in probability theory.
JOURNAL OF RUSSIAN LASER RESEARCH
(2022)
Article
Optics
E. O. Kiktenko, A. S. Zelenetsky, A. K. Fedorov
Summary: This article develops an unconditionally secure signature scheme that guarantees authenticity and transferability of messages in a QKD network. The scheme is compatible with currently available QKD devices and has been comprehensively analyzed for security.
