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staq– A full-stack quantum processing toolkit

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arXiv 2019年

作者： Gheorghiu, Vlad Amy, Matthew softwareQ Inc. KitchenerON Canada Department of Mathematics & Statistics Dalhousie University HalifaxNS Canada Institute for Quantum Computing University of Waterloo WaterlooON Canada Department of Combinatorics and Optimization University of Waterloo WaterlooON Canada

We describe staq, a full-stack quantum processing toolkit written in standard C++. staq is a quantum compiler toolkit, comprising of tools that range from quantum optimizers and translators to physical mappers for quantum devices with restricted connectives. The design of staq is inspired from the UNIX philosophy of "less is more", i.e. staq achieves complex functionality via combining (piping) small tools, each of which performs a single task using the most advanced current state-of-the-art methods. We also provide a set of illustrative benchmarks. Copyright © 2019, The Authors. All rights reserved.

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Discovery of resonating integration modes in triple-mode high-amplitude δ Scuti stars: a new evolutionary phase indicator

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arXiv 2025年

作者： Niu, Jia-Shu Xue, Hui-Fang Institute of Theoretical Physics Shanxi University Taiyuan030006 China State Key Laboratory of Quantum Optics Technologies and Devices Shanxi University Taiyuan030006 China Collaborative Innovation Center of Extreme Optics Shanxi University Taiyuan030006 China Department of Physics Taiyuan Normal University Jinzhong030619 China Institute of Computational and Applied Physics Taiyuan Normal University Jinzhong030619 China Shanxi Key Laboratory for Intelligent Optimization Computing and Blockchain Technology Jinzhong030619 China

High-amplitude δ Scuti stars (HADS) that pulsate in their first three radial modes are rare in current samples. Here, we analyse five such triple-mode HADS observed by the Transiting Exoplanet Survey Satellite (TESS) and report that the previously considered second overtone mode (f2) is actually the non-radial component of a resonating integration mode (RI mode, resulting from resonance between a radial p-mode and a non-radial p-g mixed mode), which shows significant amplitude and frequency variations over short timescales (approximately 20 days). This RI mode appears to be widespread among these stars. Notably, all five stars are in the post-main sequence evolutionary phase, actively crossing the Hertzsprung gap. These stars offer valuable insights into stellar evolution during the Hertzsprung gap, which is one of the most rapid evolutionary stages in a star’s life. © 2025, CC BY.

关键词： Image retrieval

Discovery of resonating integration modes in triple-mode high-amplitude δ Scuti stars: A new evolutionary phase indicator

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Astronomy and Astrophysics 2025年 697卷

关键词： Image retrieval

Quantifying quantum speedups: Improved classical simulation from tighter magic monotones

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arXiv 2020年

作者： Seddon, James R. Regula, Bartosz Pashayan, Hakop Ouyang, Yingkai Campbell, Earl T. Department of Physics and Astronomy University College London London United Kingdom School of Physical and Mathematical Sciences Nanyang Technological University 637371 Singapore Institute for Quantum Computing Department of Combinatorics and Optimization University of Waterloo ONN2L 3G1 Canada Perimeter Institute for Theoretical Physics WaterlooONN2L 2Y5 Canada Centre for Engineered Quantum Systems School of Physics The University of Sydney SydneyNSW2006 Australia Department of Physics & Astronomy University of Sheffield SheffieldS3 7RH United Kingdom AWS Center for Quantum Computing PasadenaCA91125 United States

Consumption of magic states promotes the stabilizer model of computation to universal quantum computation. Here, we propose three different classical algorithms for simulating such universal quantum circuits, and characterize them by establishing precise connections with a family of magic monotones. Our first simulator introduces a new class of quasiprobability distributions and connects its runtime to a generalized notion of negativity. We prove that this algorithm has significantly improved exponential scaling compared to all prior quasiprobability simulators for qubits. Our second simulator is a new variant of the stabilizer-rank simulation algorithm, extended to work with mixed states and with significantly improved runtime bounds. Our third simulator trades precision for speed by discarding negative quasiprobabilities. We connect each algorithm’s performance to a corresponding magic monotone and, by comprehensively characterizing the monotones, we obtain a precise understanding of the simulation runtime and error bounds. Our analysis reveals a deep connection between all three seemingly unrelated simulation techniques and their associated monotones. For tensor products of single-qubit states, we prove that our monotones are all equal to each other, multiplicative and efficiently computable, allowing us to make clear-cut comparisons of the simulators’ performance scaling. Furthermore, our monotones establish several asymptotic and non-asymptotic bounds on state interconversion and distillation rates. Beyond the theory of magic states, our classical simulators can be adapted to other resource theories under certain axioms, which we demonstrate through an explicit application to the theory of quantum coherence. Copyright © 2020, The Authors. All rights reserved.

关键词： Simulators

Period Variation Rates of Four Radial Single-Mode High-Amplitude Delta Scuti Stars

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arXiv 2025年

作者： Ma, Tian-Fang Niu, Jia-Shu Xue, Hui-Fang Institute of Theoretical Physics Shanxi University Taiyuan030006 China State Key Laboratory of Quantum Optics Technologies and Devices Shanxi University Taiyuan030006 China Collaborative Innovation Center of Extreme Optics Shanxi University Taiyuan030006 China Department of Physics Taiyuan Normal University Jinzhong030619 China Institute of Computational and Applied Physics Taiyuan Normal University Jinzhong030619 China Shanxi Key Laboratory for Intelligent Optimization Computing and Blockchain Technology Jinzhong030619 China

In this work, we present a study on the long time-scale period variations of four single-mode high-amplitude delta Scuti stars (HADS) via the classical O − C analysis. The target HADS are (i) XX Cygni, (ii) YZ Bootis, (iii) GP Andromedae, and (iv) ZZ Microscopii. The newly determined times of maximum light came from the Transiting Exoplanet Survey Satellite (TESS), American Association of Variable Star Observers (AAVSO), and Bundesdeutsche Arbeitsgemeinschaft für Veränderliche Sterne (BAV) projects. Together with the times of maximum light obtained in the historical literature, the O − C analysis was performed on these HADS, in which we obtained the linear period variation rates P/P as (9.2 ± 0.2) × 10−9 yr−1, (3.2 ± 0.2) × 10−9 yr−1, (4.22 ± 0.03) × 10−8 yr−1, and (−2.06 ± 0.02) × 10−8 yr−1, respectively. Based on these results and some earlier research, we also discuss the evolutionary stages and the mechanisms of the period variation of these four HADS. © 2025, CC BY.

关键词： Pulsars

Upper bounds on device-independent quantum key distribution rates and a revised Peres conjecture

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arXiv 2020年

作者： Leditzky, Felix Arnon-Friedman, Rotem Perimeter Institute for Theoretical Physics WaterlooONN2L 2Y5 Canada Department of Combinatorics and Optimization University of Waterloo WaterlooONN2L 3G1 Canada Institute for Quantum Computing University of Waterloo WaterlooONN2L 3G1 Canada EECS Department University of California Berkeley BerkeleyCA94720 United States JILA & Center for Theory of Quantum Matter University of Colorado Boulder BoulderCO80309 United States

Device-independent quantum key distribution (DIQKD) is one of the most challenging tasks in quantum cryptography. The protocols and their security are based on the existence of Bell inequalities and the ability to violate them by measuring entangled states. We study the entanglement needed for DIQKD protocols in two different ways. Our first contribution is the derivation of upper bounds on the key rates of CHSH-based DIQKD protocols in terms of the violation of the inequality;this sets an upper limit on the possible DI key extraction rate from states with a given violation. Our upper bound improves on the previously known bound of Kaur et al. Our second contribution is the initiation of the study of the role of bound entangled states in DIQKD. We present a revised Peres conjecture stating that such states cannot be used as a resource for DIQKD. We give a first piece of evidence for the conjecture by showing that the bound entangled state found by Vertesi and Brunner, even though it can certify DI randomness, cannot be used to produce a key using protocols analogous to the well-studied CHSH-based DIQKD protocol. Copyright © 2020, The Authors. All rights reserved.

关键词： quantum cryptography

Communication Complexity of One-Shot Remote State Preparation

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Communication Complexity of One-Shot Remote State Preparatio...

作者： Bab Hadiashar, Shima Nayak, Ashwin Renner, Renato Department of Combinatorics and Optimization Institute for Quantum Computing University of Waterloo WaterlooN2L 3G1 Canada Institute for Theoretical Physics ETH Zurich Zurich8093 Switzerland

quantum teleportation uses prior shared entanglement and classical communication to send an unknown quantum state from one party to another. Remote state preparation (RSP) is a similar distributed task in which the sender knows the entire classical description of the state to be sent. (This may also be viewed as the task of nonoblivious compression of a single sample from an ensemble of quantum states.) We study the communication complexity of approximate RSP (ARSP) in which the goal is to prepare an approximation of the desired quantum state. Jain (Quant. Inf. Comp., 2006) showed that the worst-case communication complexity of ARSP can be bounded from above in terms of the maximum possible information in an encoding. He also showed that this quantity is a lower bound for communication complexity of (exact) remote state preparation. In this paper, we tightly characterize the worst-case and average-case communication complexity of remote state preparation in terms of nonasymptotic information-theoretic quantities. We also show that the average-case communication complexity of RSP can be much smaller than the worst-case one. In the process, we show that n bits cannot be communicated with less than n transmitted bits in local operations and classical communication protocols. This strengthens a result due to Nayak and Salzman (J. ACM, 2006) and may be of independent interest. © 1963-2012 IEEE.

关键词： Information theory

Classical algorithms for quantum mean values

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arXiv 2019年

作者： Bravyi, Sergey Gosset, David Movassagh, Ramis IBM Research Yorktown HeightsNY10598 United States Institute for Quantum Computing University of Waterloo Canada Department of Combinatorics and Optimization University of Waterloo Canada IBM Research CambridgeMA02142 United States

We consider the task of estimating the expectation value of ann-qubit tensor product observableO1⊗O2⊗⋯⊗Onin the output state of a shallow quantum circuit. This task is a cornerstone of variational quantum algorithms for optimization, machine learning, and the simulation of quantum many-body systems. Here we study its computational complexity for constant-depth quantum circuits and three types of single-qubit observablesOjwhich are (a) close to the identity, (b) positive semidefinite, (c) arbitrary. It is shown that the mean value problem admits a classical approximation algorithm with runtime scaling aspoly(n)and2O~(n√)in cases (a,b) respectively. In case (c) we give a linear-time algorithm for geometrically local circuits on a two-dimensional grid. The mean value is approximated with a small relative error in case (a), while in cases (b,c) we satisfy a less demanding additive error bound. The algorithms are based on (respectively) Barvinok's polynomial interpolation method, a polynomial approximation for the OR function arising from quantum query complexity, and a Monte Carlo method combined with Matrix Product State techniques. We also prove a technical lemma characterizing a zero-free region for certain polynomials associated with a quantum circuit, which may be of independent interest. Copyright © 2019, The Authors. All rights reserved.

关键词： Approximation algorithms

Adaptive estimation of quantum observables

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arXiv 2021年

作者： Shlosberg, Ariel Jena, Andrew J. Mukhopadhyay, Priyanka Haase, Jan F. Leditzky, Felix Dellantonio, Luca JILA University of Colorado National Institute of Standards and Technology BoulderCO80309 United States Department of Physics University of Colorado BoulderCO80309 United States Institute for Quantum Computing University of Waterloo WaterlooONN2L 3G1 Canada Department of Combinatorics & Optimization University of Waterloo WaterlooONN2L 3G1 Canada Department of Physics & Astronomy University of Waterloo WaterlooONN2L 3G1 Canada Institute of Theoretical Physics and IQST Universität Ulm UlmD-89069 Germany Department of Mathematics IQUIST University of Illinois Urbana-Champaign UrbanaIL61801 United States Perimeter Institute for Theoretical Physics WaterlooONN2L 2Y5 Canada Department of Physics and Astronomy University of Exeter Stocker Road ExeterEX4 4QL United Kingdom

The accurate estimation of quantum observables is a critical task in science. With progress on the hardware, measuring a quantum system will become increasingly demanding, particularly for variational protocols that require extensive sampling. Here, we introduce a measurement scheme that adaptively modifies the estimator based on previously obtained data. Our algorithm, which we call AEQuO, continuously monitors both the estimated average and the associated error of the considered observable, and determines the next measurement step based on this information. We allow both for overlap and non-bitwise commutation relations in the subsets of Pauli operators that are simultaneously probed, thereby maximizing the amount of gathered information. AEQuO comes in two variants: a greedy bucket-filling algorithm with good performance for small problem instances, and a machine learning-based algorithm with more favorable scaling for larger instances. The measurement configuration determined by these subroutines is further post-processed in order to lower the error on the estimator. We test our protocol on chemistry Hamiltonians, for which AEQuO provides error estimates that improve on all state-of-the-art methods based on various grouping techniques or randomized measurements, thus greatly lowering the toll of measurements in current and future quantum applications. © 2021, CC BY.

关键词： Errors