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Related papers: Quantum advantages for Pauli channel estimation

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The accurate estimation of quantum observables is a critical task in science. With progress on the hardware, measuring a quantum system will become increasingly demanding, particularly for variational protocols that require extensive…

The dependence of quantum algorithms on state fidelity is difficult to characterize analytically and is best explored experimentally as hardware scales and noisy simulations become intractable. While low fidelity states are often…

Quantum Physics · Physics 2025-05-09 Erika Lloyd , Alexandre Fleury , Marc P. Coons , James Brown , Maritza Hernandez

Several methods, known as Quantum Process Tomography, are available to characterize the evolution of quantum systems, a task of crucial importance. However, their complexity dramatically increases with the size of the system. Here we…

The role of complex numbers in quantum theory extends beyond mathematical convenience, having recently been formalized as a resource under the framework of the resource theory of imaginarity. Operationally, imaginarity translates into using…

Quantum Physics · Physics 2026-04-15 Indranil Biswas , Subrata Bera , Ujjwal Sen , Indrani Chattopadhyay , Debasis Sarkar

Quantum error correction assisted by entanglement helps to transmit the encoded qudits through quantum channels with some of them being noiseless. Here we consider a more realistic scheme for experiments what we called as partial-noisy…

Quantum Physics · Physics 2012-09-03 Zhuo Wang , Sixia Yu , Heng Fan , C. H. Oh

Quantum computing is an information processing paradigm that uses quantum-mechanical properties to speedup computationally hard problems. Although promising, existing gate-based quantum computers consist of only a few dozen qubits and are…

Quantum Physics · Physics 2021-08-26 Ramin Ayanzadeh , Poulami Das , Swamit S. Tannu , Moinuddin Qureshi

We present a new technique to reduce the expected number of measurements to declare an unknown quantum state as entangled. Our method is based on the geometric criterion and so requires only local Pauli measurements. Using concentration of…

Quantum Physics · Physics 2017-09-13 Bingjie Wang , Stephen Brierley

A nonlocal quantum approach is presented to polarimetry, leveraging the phenomenon of entanglement in photon pairs to enhance the precision in sample property determination. By employing two distinct channels, one containing the sample of…

Quantum Physics · Physics 2025-01-30 Ali Pedram , Vira R. Besaga , Frank Setzpfandt , Özgür E. Müstecaplıoğlu

Quantum metrology with entangled states in realistic noisy environments always suffers from decoherence. Therefore, the measurement precision is greatly reduced. Here we applied the dynamical decoupling method to protect the $N$-qubit…

Quantum Physics · Physics 2016-12-21 Yang Dong , Xiang-Dong Chen , Guang-Can Guo , Fang-Wen Sun

Variational quantum algorithms (VQAs) are promising tools for demonstrating quantum utility on near-term quantum hardware, with applications in optimisation, quantum simulation, and machine learning. While researchers have studied how easy…

Quantum Physics · Physics 2026-02-06 Connor van Rossum , Sally Shrapnel , Riddhi Gupta

Quantum illumination is an entanglement-based target detection protocol that provides quantum advantages despite the presence of entanglement-breaking noise. However, the advantage of traditional quantum illumination protocols is limited to…

Quantum Physics · Physics 2024-06-26 Xiaobin Zhao , Zheshen Zhang , Quntao Zhuang

Quantum simulation, the study of strongly correlated quantum matter using synthetic quantum systems, has been the most successful application of quantum computers to date. It often requires determining observables with high precision, for…

Parameterized quantum circuits are attractive candidates for potential quantum advantage in the near term and beyond. At the same time, as quantum computing hardware not only continues to improve but also begins to incorporate new features…

Quantum Physics · Physics 2024-03-19 Tobias Stollenwerk , Stuart Hadfield

In this work we make progress in understanding the relationship between learning models with access to entangled, separable and statistical measurements in the quantum statistical query (QSQ) model. To this end, we show the following…

Quantum Physics · Physics 2023-12-12 Srinivasan Arunachalam , Vojtech Havlicek , Louis Schatzki

Accurately estimating properties of quantum states, such as entanglement, while essential for the development of quantum technologies, remains a challenging task. Standard approaches to property estimation rely on detailed modeling of the…

We propose a method of manipulating a quantum register remotely with the help of a single ancilla that steers the evolution of the register. The fully controlled ancilla qubit is coupled to the computational register solely via a fixed…

Quantum Physics · Physics 2010-08-12 Janet Anders , Daniel K. L. Oi , Elham Kashefi , Dan E. Browne , Erika Andersson

We describe a method to enhance the sensitivity of precision measurements that takes advantage of a quantum sensor's environment to amplify its response to weak external perturbations. An individual qubit is used to sense the dynamics of…

Quantum Physics · Physics 2013-05-29 G. Goldstein , P. Cappellaro , J. R. Maze , J. S. Hodges , L. Jiang , A. S. Sørensen , M. D. Lukin

We present a polynomial-time classical algorithm for estimating expectation values of arbitrary observables on typical quantum circuits under any incoherent local noise, including non-unital or dephasing. Although previous research…

Quantum Physics · Physics 2026-04-23 Armando Angrisani , Antonio A. Mele , Manuel S. Rudolph , M. Cerezo , Zoë Holmes

Quantum illumination (QI) is an entanglement-based protocol for improving lidar/radar detection of unresolved targets beyond what a classical lidar/radar of the same average transmitted energy can do. Originally proposed by Lloyd as a…

Quantum Physics · Physics 2024-09-20 Jeffrey H. Shapiro

We give a capacity formula for the classical information transmission over a noisy quantum channel, with separable encoding by the sender and limited resources provided by the receiver's pre-shared ancilla. Instead of a pure state, we…

Quantum Physics · Physics 2017-05-22 Quntao Zhuang , Elton Yechao Zhu , Peter W. Shor
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