English
Related papers

Related papers: Contractive Unitary and Classical Shadow Tomograph…

200 papers

Quantum shadow tomography based on the classical shadow representation provides an efficient way to estimate properties of an unknown quantum state without performing a full quantum state tomography. In scenarios where estimating the…

Quantum Physics · Physics 2026-03-13 Aniket Sengupta , Arijit Chatterjee , G. J. Sreejith , T. S. Mahesh

Interfacing quantum and classical processors is an important subroutine in full-stack quantum algorithms. The so-called "classical shadow" method efficiently extracts essential classical information from quantum states, enabling the…

Quantum Physics · Physics 2025-09-11 Shuowei Ma , Junyu Liu

A crucial subroutine for various quantum computing and communication algorithms is to efficiently extract different classical properties of quantum states. In a notable recent theoretical work by Huang, Kueng, and Preskill [Nat. Phys. 16,…

Quantum Physics · Physics 2021-11-19 Ting Zhang , Jinzhao Sun , Xiao-Xu Fang , Xiao-Ming Zhang , Xiao Yuan , He Lu

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

Classical shadows provide a versatile framework for estimating many properties of quantum states from repeated, randomly chosen measurements without requiring full quantum state tomography. When prior information is available, such as…

Quantum Physics · Physics 2026-05-27 Jacob Bringewatt , Henry Froland , Andreas Elben , Niklas Mueller

Quantum process tomography is a powerful tool for understanding quantum channels and characterizing properties of quantum devices. Inspired by recent advances using classical shadows in quantum state tomography [H.-Y. Huang, R. Kueng, and…

Quantum Physics · Physics 2024-02-12 Ryan Levy , Di Luo , Bryan K. Clark

Classical shadow tomography has become a powerful tool in learning about quantum states prepared on a quantum computer. Recent works have used classical shadows to variationally enforce N-representability conditions on the 2-particle…

Quantum state tomography is a fundamental task in quantum information science, enabling detailed characterization of correlations, entanglement, and electronic structure in quantum systems. However, its exponential measurement and…

Estimating expectation values is a key subroutine in quantum algorithms. Near-term implementations face two major challenges: a limited number of samples required to learn a large collection of observables, and the accumulation of errors in…

Quantum Physics · Physics 2024-06-18 Andrew Zhao , Akimasa Miyake

In quantum information theory, the accurate estimation of observables is pivotal for quantum information processing, playing a crucial role in compute and communication protocols. This work introduces a novel technique for estimating such…

Quantum Physics · Physics 2024-09-17 Andrea Caprotti , Joshua Morris , Borivoje Dakić

Obtaining precise estimates of quantum observables is a crucial step of variational quantum algorithms. We consider the problem of estimating expectation values of molecular Hamiltonians, obtained on states prepared on a quantum computer.…

Quantum Physics · Physics 2020-06-30 Charles Hadfield , Sergey Bravyi , Rudy Raymond , Antonio Mezzacapo

Classical shadow tomography provides a randomized scheme for approximating the quantum state and its properties at reduced computational cost with applications in quantum computing. In this Letter we present an algorithm for realizing fewer…

Quantum Physics · Physics 2023-12-20 Irma Avdic , David A. Mazziotti

Shadow tomography aims to build a classical description of a quantum state from a sequence of simple random measurements. Physical observables are then reconstructed from the resulting classical shadow. Shadow protocols which use…

Quantum Physics · Physics 2024-08-14 Sumner N. Hearth , Michael O. Flynn , Anushya Chandran , Chris R. Laumann

Classical shadow tomography, harnessing randomized informationally complete (IC) measurements, provides an effective avenue for predicting many properties of unknown quantum states with sample-efficient precision. Projections onto $2^n+1$…

Quantum Physics · Physics 2023-12-22 Yu Wang , Wei Cui

We introduce a method that allows one to infer many properties of a quantum state -- including nonlinear functions such as R\'enyi entropies -- using only global control over the constituent degrees of freedom. In this protocol, the state…

Quantum Physics · Physics 2023-11-20 Max McGinley , Michele Fava

We introduce "holographic shadows", a new class of randomized measurement schemes for classical shadow tomography that achieves the optimal scaling of sample complexity for learning geometrically local Pauli operators at any length scale,…

Quantum Physics · Physics 2025-12-30 Shuhan Zhang , Xiaozhou Feng , Matteo Ippoliti , Yi-Zhuang You

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

A scalable Bayesian machine learning framework is introduced for estimating scalar properties of an unknown quantum state from measurement data, which bypasses full density matrix reconstruction. This work is the first to integrate the…

Quantum Physics · Physics 2025-12-08 Hyunho Cha , Wonjung Kim , Jungwoo Lee

Extracting information efficiently from quantum systems is a major component of quantum information processing tasks. Randomized measurements, or classical shadows, enable predicting many properties of arbitrary quantum states using few…

Robust, accurate and efficient quantum tomography is key for future quantum technologies. Traditional methods are impractical for even medium sized systems and are not robust against noise and errors. Here we report on an experimental…

Quantum Physics · Physics 2016-07-27 Robert J. Chapman , Christopher Ferrie , Alberto Peruzzo