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Related papers: Efficient quantum tomography II

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Quantum tomography is a fundamental technique for characterizing, benchmarking, and verifying quantum states and devices. It plays a crucial role in advancing quantum technologies and deepening our understanding of quantum mechanics.…

Quantum communication enables the implementation of tasks that are unachievable with classical resources. However, losses on the communication channel preclude the direct long-distance transmission of quantum information in many relevant…

Quantum Physics · Physics 2021-11-02 Boxi Li , Tim Coopmans , David Elkouss

This work advances the theoretical understanding of quantum learning by establishing a new family of upper bounds on the expected generalization error of quantum learning algorithms, leveraging the framework introduced by Caro et al. (2024)…

Quantum Physics · Physics 2026-04-20 Naqueeb Ahmad Warsi , Ayanava Dasgupta , Masahito Hayashi

Probabilistic language models, e.g. those based on an LSTM, often face the problem of finding a high probability prediction from a sequence of random variables over a set of tokens. This is commonly addressed using a form of greedy decoding…

Quantum Physics · Physics 2021-05-03 Johannes Bausch , Sathyawageeswar Subramanian , Stephen Piddock

Only a few classes of quantum algorithms are known which provide a speed-up over classical algorithms. However, these and any new quantum algorithms provide important motivation for the development of quantum computers. In this article new…

Quantum Physics · Physics 2009-02-04 Lian-Ao Wu , Mark S. Byrd

Quantum state tomography is the fundamental physical task of learning a complete classical description of an unknown state of a quantum system given coherent access to many identical samples of it. The complexity of this task is commonly…

Quantum Physics · Physics 2026-05-25 Yanglin Hu , Enrique Cervero-Martín , Elias Theil , Laura Mančinska , Marco Tomamichel

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

Quantum state tomography (QST), the process of reconstructing some unknown quantum state $\hat\rho$ from repeated measurements on copies of said state, is a foundationally important task in the context of quantum computation and simulation.…

Quantum Physics · Physics 2025-10-21 Nathan Keenan , John Goold , Alex Nico-Katz

We establish optimal Statistical Query (SQ) lower bounds for robustly learning certain families of discrete high-dimensional distributions. In particular, we show that no efficient SQ algorithm with access to an $\epsilon$-corrupted binary…

Data Structures and Algorithms · Computer Science 2022-06-10 Ilias Diakonikolas , Daniel M. Kane , Yuxin Sun

Quantum simulation is a promising pathway toward practical quantum advantage by simulating large-scale quantum systems. In this work, we propose communication-efficient distributed quantum simulation protocols by exploring three quantum…

Quantum Physics · Physics 2024-11-06 Tianfeng Feng , Jue Xu , Wenjun Yu , Zekun Ye , Penghui Yao , Qi Zhao

We develop a theory for long-distance quantum key distribution based on concatenated entanglement swapping using parametric down-conversion sources and show numerical results of our model. The model incorporates practical resources…

Quantum Physics · Physics 2016-02-09 Aeysha Khalique , Barry C. Sanders

The outcome statistics of an informationally complete quantum measurement for a system in a given state can be used to evaluate the ensemble expectation of any linear operator in the same state, by averaging a function of the outcomes that…

Quantum Physics · Physics 2009-12-21 G. M. D'Ariano , D. F. Magnani , P. Perinotti

We build a general quantum state tomography framework that makes use of machine learning techniques to reconstruct quantum states from a given set of coincidence measurements. For a wide range of pure and mixed input states we demonstrate…

Quantum Physics · Physics 2020-06-09 Sanjaya Lohani , Brian T. Kirby , Michael Brodsky , Onur Danaci , Ryan T. Glasser

In this work, we initiate the study of learning quantum processes from quantum statistical queries. We focus on two fundamental learning tasks in this new access model: shadow tomography of quantum processes and process tomography with…

Quantum Physics · Physics 2025-05-14 Chirag Wadhwa , Mina Doosti

Tomograms are obtained as probability distributions and are used to reconstruct a quantum state from experimentally measured values. We study the evolution of tomograms for different quantum systems, both finite and infinite dimensional. In…

Quantum Physics · Physics 2022-06-10 Kishore Thapliyal , Subhashish Banerjee , Anirban Pathak

Quantum tomography is a cornerstone of quantum information science, enabling the reconstruction of states and channels from experimental data. Here we introduce a new paradigm, temporal state tomography (TST), for reconstructing quantum…

Quantum Physics · Physics 2026-05-05 Zhian Jia

Quantum state tomography (QST), the task of estimating an unknown quantum state given measurement outcomes, is essential to building reliable quantum computing devices. Whereas computing the maximum-likelihood (ML) estimate corresponds to…

Machine Learning · Computer Science 2022-08-30 Chien-Ming Lin , Yu-Ming Hsu , Yen-Huan Li

Quantum-inspired classical algorithms has received much attention due to its exponential speedup compared to existing algorithms, under certain data storage assumptions. The improvements are noticeable in fundamental linear algebra tasks.…

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

Amongst the multitude of state reconstruction techniques, the so-called "quantum tomography" seems to be the most fruitful. In this letter, I will start by developing the mathematical apparatus of quantum tomography and, later, I will…

Quantum Physics · Physics 2007-05-23 M. Paini

We present several new examples of speed-ups obtainable by quantum algorithms in the context of property testing. First, motivated by sampling algorithms, we consider probability distributions given in the form of an oracle $f:[n]\to[m]$.…

Quantum Physics · Physics 2010-05-13 Sourav Chakraborty , Eldar Fischer , Arie Matsliah , Ronald de Wolf