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Quantum process tomography conventionally uses a multitude of initial quantum states and then performs state tomography on the process output. Here we propose and study an alternative approach which requires only a single (or few) known…

Quantum Physics · Physics 2023-11-09 Irene López Gutiérrez , Felix Dietrich , Christian B. Mendl

We introduce a fast and accurate heuristic for adaptive tomography that addresses many of the limitations of prior methods. Previous approaches were either too computationally intensive or tailored to handle special cases such as single…

Quantum Physics · Physics 2017-11-16 Christopher Granade , Christopher Ferrie , Steven T. Flammia

Quantum computing promises to revolutionize various fields, yet the execution of quantum programs necessitates an effective compilation process. This involves strategically mapping quantum circuits onto the physical qubits of a quantum…

Quantum Physics · Physics 2024-12-19 Tian Li , Xiao-Yue Xu , Chen Ding , Tian-Ci Tian , Wei-You Liao , Shuo Zhang , He-Liang Huang

Counting statistics of charge transfers in a point contact interacting with an arbitrary quantum system is studied. The theory for the charge specific density matrix is developed, allowing the evaluation of the probability of the outcome of…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 J. Rammer , A. L. Shelankov , J. Wabnig

In this work we extend the quantum channel detection method developed in [Phys. Rev. A 88, 042335 (2013)] and [Phys. Script. T153, 014044 (2013)] in order to detect other interesting convex sets of quantum channels. First we work out a…

Quantum Physics · Physics 2013-12-18 C. Macchiavello , M. Rossi

Characterizing a quantum system by learning its state or evolution is a fundamental problem in quantum physics and learning theory with a myriad of applications. Recently, as a new approach to this problem, the task of agnostic state…

Quantum Physics · Physics 2025-12-25 Chirag Wadhwa , Laura Lewis , Elham Kashefi , Mina Doosti

This paper reports a novel method for supervised machine learning based on the mathematical formalism that supports quantum mechanics. The method uses projective quantum measurement as a way of building a prediction function. Specifically,…

Quantum Physics · Physics 2022-08-30 Fabio A. González , Vladimir Vargas-Calderón , Herbert Vinck-Posada

In this work we propose a simple optical architecture, based on phase-only programmable spatial light modulators, in order to characterize general processes on photonic spatial quantum systems in a $d>2$ Hilbert space. We demonstrate the…

Quantum Physics · Physics 2023-01-27 Juan José Miguel Varga , Lorena Rebón , Quimey Pears Stefano , Claudio Iemmi

Characterization of quantum objects, being them states, processes, or measurements, complemented by previous knowledge about them is a valuable approach, especially as it leads to routine procedures for real-life components. To this end,…

Quantum Physics · Physics 2023-06-28 Massimiliano Guarneri , Ilaria Gianani , Marco Barbieri , Andrea Chiuri

We present a compressive quantum process tomography scheme that fully characterizes any rank-deficient completely-positive process with no a priori information about the process apart from the dimension of the system on which the process…

We introduce new rounding methods to improve the accuracy of finite precision quantum arithmetic. These quantum rounding methods are applicable when multiple samples are being taken from a quantum program. We show how to use multiple…

Quantum Physics · Physics 2021-08-18 Rajiv Krishnakumar , William Zeng

Quantum algorithms for diverse problems, including search and optimization problems, require the implementation of a reflection operator over a target state. Commonly, such reflections are approximately implemented using phase estimation.…

Quantum Physics · Physics 2018-03-08 Anirban Narayan Chowdhury , Yigit Subasi , Rolando D. Somma

We propose a quantum process tomography scheme that utilizes two-mode squeezed vacuum to realize the parameter estimation with Heisenberg scaling. The objective is to estimate a rotating angle of polarization and parity detection is used as…

Quantum Physics · Physics 2018-06-27 Jian-Dong Zhang , Zi-Jing Zhang , Long-Zhu Cen , Yuan Zhao

Image processing is one of the most promising applications for quantum machine learning (QML). Quanvolutional Neural Networks with non-trainable parameters are the preferred solution to run on current and near future quantum devices. The…

Quantum Physics · Physics 2024-10-10 Daniele Lizzio Bosco , Beatrice Portelli , Giuseppe Serra

Quantum computing is emerging as a new computational paradigm with the potential to transform several research fields, including quantum chemistry. However, current hardware limitations (including limited coherence times, gate infidelities,…

Phase estimation algorithms are key protocols in quantum information processing. Besides applications in quantum computing, they can also be employed in metrology as they allow for fast extraction of information stored in the quantum state…

Quantum Physics · Physics 2018-07-03 S. Danilin , A. V. Lebedev , A. Vepsäläinen , G. B. Lesovik , G. Blatter , G. S. Paraoanu

Quantum mechanics establishes the ultimate limit to the scaling of the precision on any parameter, by iden- tifying optimal probe states and measurements. While this paradigm is, at least in principle, adequate for the metrology of quantum…

We present the first NMR implementation of a scheme for selective and efficient quantum process tomography without ancilla. We generalize this scheme such that it can be implemented efficiently using only a set of measurements involving…

Quantum Physics · Physics 2018-02-09 Akshay Gaikwad , Diksha Rehal , Amandeep Singh , Arvind , Kavita Dorai

Quantum process tomography, the task of estimating an unknown quantum channel, is a central problem in quantum information theory. A long-standing open question is to determine the optimal number of uses of an unknown channel required to…

Quantum Physics · Physics 2026-01-19 Antonio Anna Mele , Lennart Bittel

Scalable characterization of quantum processors is crucial for mitigating noise and imperfections. While randomized measurement protocols enable efficient access to local observables, inferring a globally consistent description of…

Quantum Physics · Physics 2026-03-10 Zidu Liu , Dominik S. Wild
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