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We introduce the concept of selective quantum state tomography or SQST, a tomographic scheme that enables a user to estimate arbitrary elements of an unknown quantum state using a fixed measurement record. We demonstrate how this may be…

Quantum Physics · Physics 2020-06-12 Joshua Morris , Borivoje Dakić

Beam quality optimization in mammography traditionally considers detection of a target obscured by quantum noise on a homogenous background. It can be argued that this scheme does not correspond well to the clinical imaging task because…

Medical Physics · Physics 2021-01-26 Erik Fredenberg , Bjorn Svensson , Mats Danielsson , Barbara Lazzari , Bjorn Cederstrom

Achieving error rates that meet or exceed the fault-tolerance threshold is a central goal for quantum computing experiments, and measuring these error rates using randomized benchmarking is now routine. However, direct comparison between…

Quantum Physics · Physics 2016-10-26 Richard Kueng , David M. Long , Andrew C. Doherty , Steven T. Flammia

Classical computation of electronic properties in large-scale materials remains challenging. Quantum computation has the potential to offer advantages in memory footprint and computational scaling. However, general and practical quantum…

Computational Physics · Physics 2025-10-14 Yiran Bai , Feng Xiong , Xueheng Kuang

A standard approach to quantum computing is based on the idea of promoting a classically simulable and fault-tolerant set of operations to a universal set by the addition of `magic' quantum states. In this context, we develop a general…

Quantum Physics · Physics 2022-04-12 Matteo Lostaglio , Alessandro Ciani

We use a meta-learning neural-network approach to analyse data from a measured quantum state. Once our neural network has been trained it can be used to efficiently sample measurements of the state in measurement bases not contained in the…

Quantum Physics · Physics 2021-07-01 Alistair W. R. Smith , Johnnie Gray , M. S. Kim

Quantum computers promise considerable speedups over classical approaches, which has raised interest from many disciplines. Since any currently available implementations suffer from noise and imperfections, achieving concrete speedups for…

Emerging Technologies · Computer Science 2023-08-16 Felix Greiwe , Tom Krüger , Wolfgang Mauerer

We find quantum signatures of classical chaos in various metrics of information gain in quantum tomography. We employ a quantum state estimator based on weak collective measurements of an ensemble of identically prepared systems. The…

Quantum Physics · Physics 2014-01-17 Vaibhav Madhok , Carlos A. Riofrío , Shohini Ghose , Ivan H. Deutsch

In quantum physics, all measured observables are subject to statistical uncertainties, which arise from the quantum nature as well as the experimental technique. We consider the statistical uncertainty of the so-called sampling method, in…

Quantum Physics · Physics 2012-06-08 Thomas Kiesel

Quantifying and verifying the control level in preparing a quantum state are central challenges in building quantum devices. The quantum state is characterized from experimental measurements, using a procedure known as tomography, which…

Quantum Physics · Physics 2021-12-28 Quoc Hoan Tran , Kohei Nakajima

Quantum device characterization via state tomography plays an important role in both validating quantum hardware and processing quantum information, but it needs the exponential number of the measurements. For the systems with XX+YY-type…

Quantum Physics · Physics 2020-11-18 Tao Xin

Quantum bits, or qubits, are the fundamental building blocks of present quantum computers. Hence, it is important to be able to characterize the state of a qubit as accurately as possible. By evaluating the qubit characterization problem…

Quantum Physics · Physics 2024-02-27 Bacui Li , Lorcan O. Conlon , Ping Koy Lam , Syed M. Assad

Accurate and precise control of large quantum systems is paramount to achieve practical advantages on quantum devices. Therefore, benchmarking the hardware errors in quantum computers has drawn significant attention lately. Existing…

Quantum Physics · Physics 2023-01-18 Bharath Hebbe Madhusudhana

We consider the task of performing quantum state tomography on a $d$-level spin qudit, using only measurements of spin projection onto different quantization axes. After introducing a basis of operators closely related to the spherical…

Quantum Physics · Physics 2021-12-22 Michael A. Perlin , Diego Barberena , Ana Maria Rey

When experimental errors are ignored in an experiment, the subsequent analysis of its results becomes questionable. We develop tests to detect systematic errors in quantum experiments where only a finite amount of data is recorded and apply…

Given an experimental set-up and a fixed number of measurements, how should one take data in order to optimally reconstruct the state of a quantum system? The problem of optimal experiment design (OED) for quantum state tomography was first…

Quantum Physics · Physics 2011-11-22 J. Nunn , B. J. Smith , G. Puentes , J. S. Lundeen , I. A. Walmsley

We introduce a genetic algorithm that designs quantum optics experiments for engineering quantum states with specific properties. Our algorithm is powerful and flexible, and can easily be modified to find methods of engineering states for a…

Quantum Physics · Physics 2023-05-01 Rosanna Nichols , Lana Mineh , Jesús Rubio , Jonathan C. F. Matthews , Paul A. Knott

Quantum state tomography is an elementary tool to fully characterize an unknown quantum state. As the quantum hardware scales up in size, the standard quantum state tomography becomes increasingly challenging due to its exponentially…

Quantum Physics · Physics 2022-12-12 Lu Zhong , Chu Guo , Xiaoting Wang

Our goal is to reconstruct tomographic images with few measurements and a low signal-to-noise ratio. In clinical imaging, this helps to improve patient comfort and reduce radiation exposure. As quantum computing advances, we propose to use…

Quantum Physics · Physics 2023-10-17 Merlin A. Nau , A. Hans Vija , Wesley Gohn , Maximilian P. Reymann , Andreas K. Maier

Quantitative Magnetic Resonance Imaging (qMRI) provides researchers insight into pathological and physiological alterations of living tissue, with the help of which researchers hope to predict (local) therapeutic efficacy early and…

Applications · Statistics 2008-07-30 Xiaoxi Zhang , Timothy D. Johnson , Roderick J. A. Little , Yue Cao