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Related papers: Adaptive Pauli Shadows for Energy Estimation

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We revisit an algorithm by Skeel et al. for computing the modified, or shadow, energy associated with the symplectic discretization of Hamiltonian systems. By rephrasing the algorithm as a Richardson extrapolation scheme arbitrary high…

Numerical Analysis · Mathematics 2014-01-06 Per Christian Moan , Jitse Niesen

We introduce a technique to estimate error-mitigated expectation values on noisy quantum computers. Our technique performs shadow tomography on a logical state to produce a memory-efficient classical reconstruction of the noisy density…

Quantum Physics · Physics 2022-03-15 Hong-Ye Hu , Ryan LaRose , Yi-Zhuang You , Eleanor Rieffel , Zhihui Wang

Classical shadows constitute a protocol to estimate the expectation values of a collection of M observables acting on O(1) qubits of an unknown n-qubit state with a number of measurements that is independent of n and that grows only…

Quantum Physics · Physics 2024-10-03 Giacomo De Palma , Tristan Klein , Davide Pastorello

Classifying phase transitions is a fundamental and complex challenge in condensed matter physics. This work proposes a framework for identifying quantum phase transitions by combining classical shadows with unsupervised machine learning. We…

Recent progress in the development of quantum technologies has enabled the direct investigation of dynamics of increasingly complex quantum many-body systems. This motivates the study of the complexity of classical algorithms for this…

Quantum Physics · Physics 2023-07-12 Dominik S. Wild , Álvaro M. Alhambra

We generalize the classical shadow tomography scheme to a broad class of finite-depth or finite-time local unitary ensembles, known as locally scrambled quantum dynamics, where the unitary ensemble is invariant under local basis…

Quantum Physics · Physics 2025-10-27 Hong-Ye Hu , Soonwon Choi , Yi-Zhuang You

The classical shadows protocol, recently introduced by Huang, Kueng, and Preskill [Nat. Phys. 16, 1050 (2020)], is a quantum-classical protocol to estimate properties of an unknown quantum state. Unlike full quantum state tomography, the…

Quantum Physics · Physics 2022-08-17 Dax Enshan Koh , Sabee Grewal

Computer-aided engineering techniques are indispensable in modern engineering developments. In particular, partial differential equations are commonly used to simulate the dynamics of physical phenomena, but very large systems are often…

Quantum Physics · Physics 2022-04-26 Yuki Sato , Ruho Kondo , Satoshi Koide , Hideki Takamatsu , Nobuyuki Imoto

Classical shadows are a powerful method for learning many properties of quantum states in a sample-efficient manner, by making use of randomized measurements. Here we study the sample complexity of learning the expectation value of Pauli…

Quantum Physics · Physics 2023-06-13 Matteo Ippoliti , Yaodong Li , Tibor Rakovszky , Vedika Khemani

Classical shadow tomography is a sample-efficient technique for characterizing quantum systems and predicting many of their properties. Circuit cutting is a technique for dividing large quantum circuits into smaller fragments that can be…

Quantum Physics · Physics 2024-05-21 Daniel T. Chen , Zain H. Saleem , Michael A. Perlin

The quantum information science community has seen a surge in new algorithmic developments across scientific domains. These developments have demonstrated polynomial or better improvements in computational and space complexity,…

Quantum Physics · Physics 2022-05-03 Vincent R. Pascuzzi , Ning Bao , Ang Li

We consider the problem of jointly estimating expectation values of many Pauli observables, a crucial subroutine in variational quantum algorithms. Starting with randomized measurements, we propose an efficient derandomization procedure…

Quantum Physics · Physics 2021-07-21 Hsin-Yuan Huang , Richard Kueng , John Preskill

Classical Shadow Tomography (Huang, Kueng and Preskill, Nature Physics 2020) is a method for creating a classical snapshot of an unknown quantum state, which can later be used to predict the value of an a-priori unknown observable on that…

Quantum Physics · Physics 2025-07-15 Zvika Brakerski , Nir Magrafta , Tomer Solomon

As quantum devices continue to grow in size but remain affected by noise, it is crucial to determine when and how they can outperform classical computers on practical tasks. A central piece in this effort is to develop the most efficient…

Recently, increased computational power and data availability, as well as algorithmic advances, have led machine learning techniques to impressive results in regression, classification, data-generation and reinforcement learning tasks.…

Calibration of large-scale differential equation models to observational or experimental data is a widespread challenge throughout applied sciences and engineering. A crucial bottleneck in state-of-the art calibration methods is the…

Optimization and Control · Mathematics 2021-02-23 Jon Cockayne , Andrew B. Duncan

Variational algorithms have particular relevance for near-term quantum computers but require non-trivial parameter optimisations. Here we propose Analytic Descent: Given that the energy landscape must have a certain simple form in the local…

Quantum Physics · Physics 2022-05-16 Bálint Koczor , Simon C. Benjamin

Gaussian building blocks are essential for photonic quantum information processing, and universality can be practically achieved by equipping Gaussian circuits with adaptive measurement and feedforward. The number of adaptive steps then…

Quantum Physics · Physics 2026-02-17 Changhun Oh , Youngrong Lim

Quantum algorithms exploiting real-time evolution under a target Hamiltonian have demonstrated remarkable efficiency in extracting key spectral information. However, the broader potential of these methods, particularly beyond ground state…

The recent literature on near-term applications for quantum computers contains several examples of the applications of hybrid quantum/classical variational approaches. This methodology can be applied to a variety of optimization problems,…

Quantum Physics · Physics 2019-01-23 Giacomo Nannicini