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Related papers: Quasiprobabilistic state-overlap estimator for NIS…

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We study the estimation of the overlap between two unknown pure quantum states of a finite dimensional system, given $M$ and $N$ copies of each type. This is a fundamental primitive in quantum information processing that is commonly…

Accurately estimating the overlap between quantum states is a fundamental task in quantum information processing. While various strategies using distinct quantum measurements have been proposed for overlap estimation, the lack of…

Quantum Physics · Physics 2025-02-13 Hao Zhan , Ben Wang , Minghao Mi , Jie Xie , Liang Xu , Aonan Zhang , Lijian Zhang

Quantum machine learning seeks a computational advantage in data processing by evaluating functions of quantum states, such as their similarity, that can be classically intractable to compute. For quantum advantage to be possible, however,…

Quantum tomography is one of the major challenges of large-scale quantum information research due to the exponential time complexity. In this work, we develop and apply a Bayesian state estimation method to experimentally demonstrate…

Quantum Physics · Physics 2025-11-13 Yang Zhengning , Shihao Ru , Lianzhen Cao , Nikolay Zheludev , Weibo Gao

The overlap measurement scheme accomplishes to evaluate the overlap of two input quantum states by only measuring an introduced auxiliary qubit, irrespective of the complexity of the two input states. We find a counterintuitive phenomenon…

Quantum Physics · Physics 2015-06-12 Chang-shui Yu , Jun Zhang , Heng Fan

Estimating the overlap between two states is an important task with several applications in quantum information. However, the typical swap test circuit can only measure a sole pair of quantum states at a time. In this study we designed a…

Quantum Physics · Physics 2022-05-17 Wen Liu , Han-Wen Yin , Zhi-Rao Wang , Wen-Qin Fan

We discuss the (re-)construction of quasiprobability representations from generic measurements, including noisy ones. Based on the measurement under study, quasiprobabilities and the associated concept of nonclassicality are introduced. A…

Quantum Physics · Physics 2025-11-07 Jan Sperling , Laura Ares , Elizabeth Agudelo

We investigate how to experimentally detect a recently proposed measure to quantify macroscopic quantum superpositions [Phys. Rev. Lett. 106, 220401 (2011)], namely, "macroscopic quantumness" $\mathcal{I}$. Schemes based on overlap…

Quantum Physics · Physics 2017-01-17 Hyunseok Jeong , Changsuk Noh , Seunglee Bae , Dimitris G. Angelakis , Timothy C. Ralph

We introduce an approximate description of an $N$-qubit state, which contains sufficient information to estimate the expectation value of any observable with precision independent of $N$. We show, in fact, that the error in the estimation…

Quantum Physics · Physics 2019-11-14 Marco Paini , Amir Kalev

Quantum computation has been growing rapidly in both theory and experiments. In particular, quantum computing devices with a large number of qubits have been developed by IBM, Google, IonQ, and others. The current quantum computing devices…

Quantum Physics · Physics 2021-02-10 Rishabh Gupta , Rongxin Xia , Raphael D. Levine , Sabre Kais

Current quantum computers have the potential to overcome classical computational methods, however, the capability of the algorithms that can be executed on noisy intermediate-scale quantum devices is limited due to hardware imperfections.…

Quantum Physics · Physics 2023-08-16 Cristian A. Galvis-Florez , Daniel Reitzner , Simo Särkkä

The presence of noise in quantum computers hinders their effective operation. Even though quantum error correction can theoretically remedy this problem, its practical realization is still a challenge. Testing and benchmarking noisy,…

Quantum Physics · Physics 2023-02-15 Adrian Ortega , Orsolya Kálmán , Tamás Kiss

We extend the concept of probabilistic unambiguous discrimination of quantum states to quantum state estimation. We consider a scenario where the measurement device can output either an estimate of the unknown input state or an inconclusive…

Quantum Physics · Physics 2009-11-13 Jaromir Fiurasek

The quantum state overlap is the textbook measure of the difference between two quantum states. Yet, it is inadequate to compare the complex configurations of many-body systems. The problem is inherited by the widely employed quantum state…

Quantum Physics · Physics 2021-06-03 Davide Girolami , Fabio Anzà

Scaling beyond individual quantum devices via distributed quantum computing relies critically on high-fidelity quantum state transfers between devices, yet the quantum interconnects needed for this are currently unavailable or expected to…

Quantum Physics · Physics 2025-07-03 Marvin Bechtold , Johanna Barzen , Frank Leymann , Alexander Mandl

Quantum metrology is a promising practical use case for quantum technologies, where physical quantities can be measured with unprecedented precision. In lieu of quantum error correction procedures, near term quantum devices are expected to…

Quantum Physics · Physics 2021-12-03 Yingkai Ouyang , Nathan Shettell , Damian Markham

We review two algorithmic advances that bring us closer to reliable quantum simulations of model systems in high energy physics and beyond on noisy intermediate-scale quantum (NISQ) devices. The first method is the dimensional expressivity…

Near-term quantum computation holds potential across multiple application domains. However, imperfect preparation and evolution of states due to algorithmic and experimental shortcomings, characteristic in the near-term implementation,…

Reconstructing the state of a complex quantum system represents a pivotal task for all quantum information applications, both for characterization purposes and for verification of quantum protocols. Recent technological developments have…

The effects of noise are one of the most important factors to consider when it comes to quantum computing in the noisy intermediate-scale quantum computing (NISQ) era that we are currently in. Therefore, it is important not only to gain…

Quantum Physics · Physics 2025-08-07 T. Piskor , M. Schöndorf , M. Bauer , D. Smith , T. Ayral , S. Pogorzalek , A. Auer , M. Papič
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