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We explore a supervised machine learning approach to estimate the entanglement entropy of multi-qubit systems from few experimental samples. We put a particular focus on estimating both aleatoric and epistemic uncertainty of the network's…

Quantum Physics · Physics 2024-01-04 Maximilian Rieger , Moritz Reh , Martin Gärttner

The phenomenon of quantum entanglement underlies several important protocols that enable emerging quantum technologies. Entangled states, however, are extremely delicate and often get perturbed by tiny fluctuations in their external…

Quantum Physics · Physics 2024-02-07 Jitendra Joshi , Mir Alimuddin , T S Mahesh , Manik Banik

Entanglement is a fundamental feature of quantum mechanics and holds great promise for enhancing metrology and communications. Much of the focus of quantum metrology so far has been on generating highly entangled quantum states that offer…

The principle of maximum likelihood reconstruction has proven to yield satisfactory results in the context of quantum state tomography for many-body systems of moderate system sizes. Until recently, however, quantum state tomography has…

Quantum Physics · Physics 2014-01-29 Tillmann Baumgratz , Alexander Nüßeler , Marcus Cramer , Martin B. Plenio

Quantum state tomography serves as a key tool for identifying quantum states generated in quantum computers and simulators, typically involving local operations on individual particles or qubits to enable independent measurements. However,…

Quantum Gases · Physics 2026-03-26 Giacomo Marmorini , Takeshi Fukuhara , Daisuke Yamamoto

We formulate an algorithm to lower bound the fidelity between quantum many-body states only from partial information, such as the one accessible by few-body observables. Our method is especially tailored to permutationally invariant states,…

Quantum Physics · Physics 2020-08-19 Matteo Fadel , Albert Aloy , Jordi Tura

We describe a resource-efficient approach to studying many-body quantum states on noisy, intermediate-scale quantum devices. We employ a sequential generation model that allows us to bound the range of correlations in the resulting…

Quantum Physics · Physics 2021-03-05 Johannes Borregaard , Matthias Christandl , Daniel Stilck França

Recent advances have demonstrated that $\mathcal{O}(\log M)$ measurements suffice to predict $M$ properties of arbitrarily large quantum many-body systems. However, these remarkable findings assume that the properties to be predicted are…

Quantum Physics · Physics 2024-10-22 Jerry Huang , Laura Lewis , Hsin-Yuan Huang , John Preskill

Predicting properties of complex, large-scale quantum systems is essential for developing quantum technologies. We present an efficient method for constructing an approximate classical description of a quantum state using very few…

Quantum Physics · Physics 2021-04-20 Hsin-Yuan Huang , Richard Kueng , John Preskill

Quantum Mechanical ground states of many-body systems can be important resources for various investigations: for quantum sensing, as the initial state for nonequilibrium quantum dynamics following quenches, and the simulation of quantum…

Quantum Physics · Physics 2025-11-18 Prashasti Tiwari , Dylan Lewis , Sougato Bose

Entanglement is a key property in the development of quantum technologies and in the study of quantum many-body simulations. However, entanglement measurement typically requires quantum full-state tomography (FST). Here we present a neural…

Quantum Physics · Physics 2022-09-20 Yulei Huang , Liangyu Che , Chao Wei , Feng Xu , Xinfang Nie , Jun Li , Dawei Lu , Tao Xin

Quantum state tomography is a fundamental tool in quantum information processing. It allows us to estimate the state of a quantum system by measuring different observables on many identically prepared copies of the system. This is, in…

Quantum Physics · Physics 2011-11-28 Carlos A. Riofrío

The experimental realisation of large scale many-body systems has seen immense progress in recent years, rendering full tomography tools for state identification inefficient, especially for continuous systems. In order to work with these…

Detecting entanglement in multipartite quantum states is an inherently probabilistic process, typically with a few measured samples. The level of confidence in entanglement detection quantifies the scheme's validity via the probability that…

We propose a method for detecting bipartite entanglement in a many-body mixed state based on estimating moments of the partially transposed density matrix. The estimates are obtained by performing local random measurements on the state,…

We consider the problem of estimating the energy of a quantum state preparation for a given Hamiltonian in Pauli decomposition. For various quantum algorithms, in particular in the context of quantum chemistry, it is crucial to have energy…

Quantum Physics · Physics 2025-08-20 Alexander Gresch , Uğur Tepe , Martin Kliesch

Calculating bounds of properties of many-body quantum systems is of paramount importance, since they guide our understanding of emergent quantum phenomena and complement the insights obtained from estimation methods. Recent semidefinite…

Quantum Physics · Physics 2026-01-16 Luke Mortimer , Leonardo Zambrano , Antonio Acín , Donato Farina

Given the state of a quantum system, one can calculate the expectation value of any observable of the system. However, the inverse problem of determining the state by performing different measurements is not a trivial task. In various…

Quantum Physics · Physics 2012-10-26 Bahar Mehmani , Theo M. Nieuwenhuizen

Quantum state tomography, the ability to deduce the density matrix of a quantum system from measured data, is of fundamental importance for the verification of present and future quantum devices. It has been realized in systems with few…

Quantum Physics · Physics 2010-02-22 M. Cramer , M. B. Plenio

We study the problems of quantum tomography and shadow tomography using measurements performed on individual, identical copies of an unknown $d$-dimensional state. We first revisit a known lower bound due to Haah et al. (2017) on quantum…

Quantum Physics · Physics 2025-06-12 Angus Lowe , Ashwin Nayak