检索结果-内蒙古大学图书馆

Trade off-free entanglement stabilization in a superconducting qutrit-qubit system

学校读者我要写书评

暂无评论

arXiv 2021年

作者： Brown, Tristan Doucet, Emery Ristè, Diego Ribeill, Guilhem Cicak, Katarina Aumentado, Joe Simmonds, Ray Govia, Luke Kamal, Archana Ranzani, Leonardo Department of Physics and Applied Physics University of Massachusetts LowellMA01854 United States Quantum Engineering and Computing Raytheon BBN Technologies CambridgeMA02138 United States National Institute of Standards and Technology 325 Broadway BoulderCO80305 United States

quantum reservoir engineering is a powerful framework for autonomous quantum state preparation and error correction. However, traditional approaches to reservoir engineering are hindered by unavoidable coherent leakage out of the target state, which imposes an inherent trade off between achievable steady-state state fidelity and stabilization rate. In this work we demonstrate a protocol that achieves trade off-free Bell state stabilization in a qutrit-qubit system realized on a circuit-QED platform. We accomplish this by creating a purely dissipative channel for population transfer into the target state, mediated by strong parametric interactions coupling the second-excited state of a superconducting transmon and the engineered bath resonator. Our scheme achieves a state preparation fidelity of 84% with a stabilization time constant of 339 ns, leading to the lowest error-time product reported in solid-state quantum information platforms to date. © 2021, CC BY.

关键词： Stabilization

Tensor-based quantum phase difference estimation for large-scale demonstration

学校读者我要写书评

暂无评论

arXiv 2024年

作者： Kanno, Shu Sugisaki, Kenji Nakamura, Hajime Yamauchi, Hiroshi Sakuma, Rei Kobayashi, Takao Gao, Qi Yamamoto, Naoki Mitsubishi Chemical Corporation Science & Innovation Center Kanagawa Yokohama227-8502 Japan Graduate School of Science and Technology Keio University 7-1 Shinkawasaki Saiwai-ku Kawasaki Kanagawa212-0032 Japan Centre for Quantum Engineering Research and Education TCG Centres for Research and Education in Science and Technology Sector V Salt Lake Kolkata700091 India Keio University 2-15-45 Mita Minato-ku Tokyo108-8345 Japan SoftBank Corp. Research Institute of Advanced Technology Tokyo105-7529 Japan Materials Informatics Initiative RD Technology & Digital Transformation Center JSR Corporation 3-103-9 Tonomachi Kawasaki-ku Kawasaki Kanagawa210-0821 Japan Department of Applied Physics and Physico-Informatics Keio University 3-14-1 Hiyoshi Kohoku-ku Kanagawa Yokohama223-8522 Japan Quantum Computing Center Keio University 3-14-1 Hiyoshi Kohoku-ku Kanagawa Yokohama223-8522 Japan

We develop an energy calculation algorithm leveraging quantum phase difference estimation (QPDE) scheme and a tensor-network-based unitary compression method in the preparation of superposition states and time-evolution gates. Alongside its efficient implementation, this algorithm reduces depolarization noise affections exponentially. We demonstrated energy gap calculations for one-dimensional Hubbard models on IBM superconducting devices using circuits up to 32-system (plus one-ancilla) qubits, a five-fold increase over previous QPE demonstrations, at the 7242 controlled-Z gate level of standard transpilation, utilizing a Q-CTRL error suppression module. Additionally, we propose a technique towards molecular executions using spatial orbital localization and index sorting, verified by a 13- (17-)qubit hexatriene (octatetraene) simulation. Since QPDE can handle the same objectives as QPE, our algorithm represents a leap forward in quantum computing on real devices. © 2024, CC BY-NC-SA.

关键词： Energy gap

Perturbative diagonalization for time-dependent strong interactions

学校读者我要写书评

暂无评论

arXiv 2021年

作者： Xiao, Z. Doucet, E. Noh, T. Ranzani, L. Simmonds, R.W. Govia, L.C.G. Kamal, Archana Department of Physics and Applied Physics University of Massachusetts LowellMA01854 United States The National Institute of Standards and Technology BoulderCO80305 United States Quantum Engineering and Computing Raytheon BBN Technologies CambridgeMA02138 United States National Institute of Standards and Technology 325 Broadway BoulderCO80305 United States

We present a systematic method to implement a perturbative Hamiltonian diagonalization based on the time-dependent Schrieffer-Wolff transformation. Applying our method to strong parametric interactions we show how, even in the dispersive regime, full Rabi model physics is essential to describe the dressed spectrum. Our results unveil several qualitatively new results including realization of large energy-level shifts, tunable in magnitude and sign with the frequency and amplitude of the pump mediating the parametric interaction. Crucially Bloch-Siegert shifts, typically thought to be important only in the ultra-strong or deep-strong coupling regimes, can be rendered large even for weak dispersive interactions to realize points of exact cancellation of dressed shifts (‘blind spots’) at specific pump frequencies. The framework developed here highlights the rich physics accessible with time-dependent interactions and serves to significantly expand the functionalities for control and readout of strongly-interacting quantum systems. © 2021, CC BY.

关键词： quantum optics

Dynamic formation of quasicondensate and spontaneous vortices in a strongly interacting Fermi gas

学校读者我要写书评

暂无评论

Physical Review Research 2021年第4期3卷 043115-043115页

作者： Xiang-Pei Liu Xing-Can Yao Youjin Deng Yu-Xuan Wang Xiao-Qiong Wang Xiaopeng Li Qijin Chen Yu-Ao Chen Jian-Wei Pan Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics University of Science and Technology of China Hefei 230026 China Shanghai Branch CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Shanghai 201315 China Shanghai Research Center for Quantum Sciences Shanghai 201315 China MinJiang Collaborative Center for Theoretical Physics College of Physics and Electronic Information Engineering Minjiang University Fuzhou 350108 China State Key Laboratory of Surface Physics Institute of Nanoelectronics and Quantum Computing and Department of Physics Fudan University Shanghai 200433 China Shanghai Qi Zhi Institute AI Tower Xuhui District Shanghai 200232 China

We report an experimental study of quench dynamics across the superfluid transition temperature Tc in a strongly interacting Fermi gas by ramping down the trapping potential. The nonzero quasicondensate number N0 at temperatures significantly above Tc in the unitary and the BEC regimes is consistent with the pseudogap physics via preformed pairs. Below Tc, a rapid growth of N0 is accompanied by the spontaneous generation of tens of vortices. We observe a power-law scaling of the vortex density versus the quasicondensate formation time, consistent with the Kibble-Zurek theory. Our work provides an example of studying emerged many-body physics by quench dynamics and paves the way for studying the quantum turbulence in a strongly interacting Fermi gas.

关键词： Fermi gases Fermionic condensates Vortices in superfluids Bose-Einstein condensates

Gapped domain walls between 2+1D topologically ordered states

学校读者我要写书评

暂无评论

Physical Review Research 2020年第2期2卷 023331-023331页

作者： Tian Lan Xueda Wen Liang Kong Xiao-Gang Wen Institute for Quantum Computing University of Waterloo Waterloo Ontario Canada N2L 3G1 Department of Physics Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA Shenzhen Institute for Quantum Science and Engineering and Department of Physics Southern University of Science and Technology Shenzhen 518055 China

The (2+1)-dimensional (2+1D) topological order can be characterized by the mapping-class-group representations for Riemann surfaces of genus 1, genus 2, etc. In this paper, we use those representations to determine the possible gapped boundaries of a 2+1D topological order, as well as the domain walls between two topological orders. We find that mapping-class-group representations for both genus-1 and genus-2 surfaces are needed to determine the gapped domain walls and boundaries. Our systematic theory is based on the fixed-point partition functions for the walls (or the boundaries), which completely characterize the gapped domain walls (or the boundaries). The mapping-class-group representations give rise to conditions that must be satisfied by the fixed-point partition functions, which leads to a systematic theory. Such conditions can be viewed as bulk topological order determining the (noninvertible) gravitational anomaly at the domain wall, and our theory can be viewed as finding all types of the gapped domain wall given a (noninvertible) gravitational anomaly. We also developed a systematic theory of gapped domain walls (boundaries) based on the structure coefficients of condensable algebras.

关键词： Topological phase transition Topological phases of matter

Indirect influence in social networks as an induced percolation phenomenon (vol 119, e2100151119, 2022)

学校读者我要写书评

暂无评论

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 2022年第24期119卷 e2100151119页

作者： Xie, Jiarong Wang, Xiangrong Feng, Ling Zhao, Jin-Hua Liu, Wenyuan Moreno, Yamir Hu, Yanqing School of Computer Science and Engineering Sun Yat-sen University 510006 Guangzhou China Institute of Future Networks Southern University of Science and Technology 518055 Shenzhen China Peng Cheng Laboratory 518066 Shenzhen China Institute of High Performance Computing A*STAR 138632 Singapore Department of Physics National University of Singapore 117551 Singapore Guangdong Provincial Key Laboratory of Nuclear Science Institute of Quantum Matter South China Normal University 510006 Guangzhou China Guangdong-Hong Kong Joint Laboratory of Quantum Matter Southern Nuclear Science Computing Center South China Normal University 510006 Guangzhou China Division of Physics and Applied Physics School of Physical and Mathematical Sciences Nanyang Technological University 637371 Singapore Institute for Biocomputation and Physics of Complex Systems University of Zaragoza 50018 Zaragoza Spain Department of Theoretical Physics University of Zaragoza 50018 Zaragoza Spain ISI Foundation 10126 Torino Italy Department of Statistics and Data Science College of Science Southern University of Science and Technology 518055 Shenzhen China

Percolation theory has been widely used to study phase transitions in network systems. It has also successfully explained various macroscopic spreading phenomena across different fields. Yet, the theoretical frameworks have been focusing on direct interactions among nodes, while recent empirical observations have shown that indirect interactions are common in many network systems like social and ecological networks, among others. By investigating the detailed mechanism of both direct and indirect influence on scientific collaboration networks, here we show that indirect influence can play the dominant role in behavioral influence. To address the lack of theoretical understanding of such indirect influence on the macroscopic behavior of the system, we propose a percolation mechanism of indirect interactions called induced percolation. Surprisingly, our model exhibits a unique anisotropy property. Specifically, directed networks show first-order abrupt transitions as opposed to the second-order continuous transition in the same network structure but with undirected links. A mix of directed and undirected links leads to rich hybrid phase transitions. Furthermore, a unique feature of the nonmonotonic pattern is observed in network connectivities near the critical point. We also present an analytical framework to characterize the proposed induced percolation, paving the way to further understanding network dynamics with indirect interactions.

关键词： percolation indirect interactions social network phase transition behavioral contagion

Application-level Benchmarking of quantum Computers using Nonlocal Game Strategies

学校读者我要写书评

暂无评论

arXiv 2023年

作者： Furches, Jim Chehade, Sarah Hamilton, Kathleen Wiebe, Nathan Marrero, Carlos Ortiz College of Computing Georgia Institute of Technology AtlantaGA30332 United States Physical Detection Systems and Deployment Division Pacific Northwest National Laboratory RichlandWA99354 United States Quantum Computational Science Group Oak Ridge National Laboratory Oak RidgeTN37830 United States Department of Computer Science University of Toronto ONM5S 1A1 Canada High Performance Computing Group Pacific Northwest National Laboratory RichlandWA99354 United States Canadian Institute for Advanced Research TorontoONM5G 1M1 Canada Department of Electrical & Computer Engineering North Carolina State University RaleighNC27607 United States

In a nonlocal game, two noncommunicating players cooperate to convince a referee that they possess a strategy that does not violate the rules of the game. quantum strategies allow players to optimally win some games by performing joint measurements on a shared entangled state, but computing these strategies can be challenging. We present a variational quantum algorithm to compute quantum strategies for nonlocal games by encoding the rules of a nonlocal game into a Hamiltonian. We show how this algorithm can generate a short-depth optimal quantum strategy for a graph coloring game with a quantum advantage. This quantum strategy is then evaluated on fourteen different quantum hardware platforms to demonstrate its utility as a benchmark. Finally, we discuss potential sources of errors that can explain the observed decreased performance of the executed task and derive an expression for the number of samples required to accurately estimate the win rate in the presence of noise. Copyright © 2023, The Authors. All rights reserved.

关键词： Qubits

Provably Efficient Simulation of 1D Long-Range Interacting Systems at Any Temperature

学校读者我要写书评

暂无评论

Physical Review Letters 2025年第19期134卷 190404-190404页

作者： Rakesh Achutha Donghoon Kim Yusuke Kimura Tomotaka Kuwahara Analytical quantum complexity RIKEN Hakubi Research Team RIKEN Center for Quantum Computing (RQC) Wako Saitama 351-0198 Japan Department of Computer Science and Engineering Indian Institute of Technology (Banaras Hindu University) Varanasi 221005 India PRESTO Japan Science and Technology (JST) Kawaguchi Saitama 332-0012 Japan RIKEN Cluster for Pioneering Research (CPR) Wako Saitama 351-0198 Japan

We introduce a method that ensures efficient computation of one-dimensional quantum systems with long-range interactions across all temperatures. Our algorithm operates within a quasipolynomial run-time for inverse temperatures up to β=poly(ln(n)). At the core of our approach is the density matrix renormalization group algorithm, which typically does not guarantee efficiency. We have created a new truncation scheme for the matrix product operator of the quantum Gibbs states, which allows us to control the error analytically. Additionally, our method can be applied to simulate the time evolution of systems with long-range interactions, achieving significantly better precision than that offered by the Lieb-Robinson bound.

关键词：

A universal quantum gate set for transmon qubits with strong ZZ interactions

学校读者我要写书评

暂无评论

arXiv 2021年

作者： Long, Junling Zhao, Tongyu Bal, Mustafa Zhao, Ruichen Barron, George S. Ku, Hsiang-Sheng Howard, Joel A. Wu, Xian McRae, Corey Rae H. Deng, Xiu-Hao Ribeill, Guilhem J. Singh, Meenakshi Ohki, Thomas A. Barnes, Edwin Economou, Sophia E. Pappas, David P. Department of Physics University of Colorado BoulderCO80309 United States Department of Physics Virginia Tech BlacksburgVA24061 United States National Institute of Standards and Technology BoulderCO80305 United States Department of Physics Colorado School of Mines GoldenCO80401 United States Shenzhen Institute of Quantum Science and Engineering Southern University of Science and Technology Shenzhen Guangdong518055 China Quantum Engineering and Computing Raytheon BBN Technologies CambridgeMA02138 United States

High-fidelity single- and two-qubit gates are essential building blocks for a fault-tolerant quantum computer. While there has been much progress in suppressing single-qubit gate errors in superconducting qubit systems, two-qubit gates still suffer from error rates that are orders of magnitude higher. One limiting factor is the residual ZZ-interaction, which originates from a coupling between computational states and higher-energy states. While this interaction is usually viewed as a nuisance, here we experimentally demonstrate that it can be exploited to produce a universal set of fast single- and two-qubit entangling gates in a coupled transmon qubit system. To implement arbitrary single-qubit rotations, we design a new protocol called the two-axis gate that is based on a three-part composite pulse. It rotates a single qubit independently of the state of the other qubit despite the strong ZZ-coupling. We achieve single-qubit gate fidelities as high as 99.1% (for |g01i ↔ |g11i transition) from randomized benchmarking measurements. We then demonstrate both a CZ gate and a CNOT gate. Because the system has a strong ZZ-interaction, a CZ gate can be achieved by letting the system freely evolve for a gate time tg = 53.8 ns. To design the CNOT gate, we utilize an analytical microwave pulse shape based on the SWIPHT protocol for realizing fast, low-leakage gates. We obtain fidelities of 94.6% and 97.8% for the CNOT and CZ gates respectively from quantum progress tomography. Copyright © 2021, The Authors. All rights reserved.

关键词： Logic gates