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The Petz recovery map is a central construct in quantum information theory, providing an explicit, channel-aware prescription for reversing the effects of noise. Unlike standard quantum operations, the Petz map is intrinsically dependent on…

We examine the longstanding problem of introducing a time observable in Quantum Mechanics; using the formalism of positive-operator-valued measures we show how to define such an observable in a natural way and we discuss some consequences.

Quantum Physics · Physics 2009-10-30 Riccardo Giannitrapani

Quantum error correction (QEC) is an essential tool for quantum computing that enables reliable information processing in the presence of noise. Syndrome measurements play a central role in QEC, making it possible to unambiguously identify…

Quantum Physics · Physics 2025-10-13 Debjyoti Biswas , Prabha Mandayam

This study proposes a new approach to quantum state recovery following measurement. Specifically, we introduce a special operation that transfers the probability amplitude of the quantum state into its orthogonal complement. This operation…

Quantum Physics · Physics 2025-10-03 Taiga Suzuki , Masayuki Ohzeki

Predictions for measurement outcomes in physical theories are usually computed by combining two distinct notions: a state, describing the physical system, and an observable, describing the measurement which is performed. In quantum theory,…

Quantum Physics · Physics 2012-03-28 Markus P. Mueller , Cozmin Ududec

Extracting classical information from quantum systems is an essential step of many quantum algorithms. However, this information could be corrupted as the systems are prone to quantum noises, and its distortion under quantum dynamics has…

Quantum Physics · Physics 2023-04-19 Xuanqiang Zhao , Benchi Zhao , Zihan Xia , Xin Wang

Objective: Despite recent advancements in quantum computing, the limited number of available qubits has hindered progress in CT reconstruction. This study investigates the feasibility of utilizing quantum annealing-based computed tomography…

Quantum Physics · Physics 2024-02-12 Akihiro Haga

Recent progress in fault-tolerant quantum computing suggests that leveraging error-syndrome information at the logical layer can substantially improve performance, including the estimation of logical observables from noisy states. In this…

Quantum Physics · Physics 2026-03-06 Kento Tsubouchi , Hyukgun Kwon , Liang Jiang , Nobuyuki Yoshioka

The accurate estimation of observables is a crucial task in quantum computing. Recent advances have highlighted the need for (a) specialized protocols for qudit-based devices, that include (b) error-aware strategies. Here, we present…

We expand the time reversal symmetry arguments of quantum mechanics, originally proposed by Wigner in the context of unitary dynamics, to contain situations including generalized measurements for monitored quantum systems. We propose a…

Quantum Physics · Physics 2020-09-04 Sreenath K. Manikandan , Andrew N. Jordan

Interactive verification protocols for quantum computations allow to build trust between a client and a service provider, ensuring the former that the instructed computation was carried out faithfully. They come in two variants, one without…

Quantum Physics · Physics 2026-04-01 Amit Saha , Harold Ollivier

Few primitives are as intertwined with the foundations of cryptography as Oblivious Transfer (OT). Not surprisingly, with the advent of quantum information processing, a major research path has emerged, aiming to minimize the requirements…

Quantum Physics · Physics 2025-06-18 Ricardo Faleiro , Manuel Goulão , Leonardo Novo , Emmanuel Zambrini Cruzeiro

Quantum measurement is a physical process. What physical resources and constraints does quantum mechanics require for measurement to produce the classical world we observe? Treating measurement as a fully unitary quantum process, our goal…

Quantum Physics · Physics 2025-12-09 Vishal Johnson , Ashmeet Singh , Reimar Leike , Philipp Frank , Torsten Enßlin

Quantum computation is one of the most promising new paradigms for the simulation of physical systems composed of electrons and atomic nuclei, with applications in chemistry, solid-state physics, materials science, and molecular biology.…

Quantum Physics · Physics 2024-11-05 Jakob Günther , Alberto Baiardi , Markus Reiher , Matthias Christandl

Although time is one of our most intuitive physical concepts, its understanding at the fundamental level is still an open question in physics. For instance, time in quantum mechanics and general relativity are two distinct and incompatible…

Quantum Physics · Physics 2021-01-27 Eduardo O. Dias

While quantum correlations between two spacelike-separated systems are fully encoded by the bipartite density operator associated with the joint system, there does not exist an analogous operator representing general quantum correlations…

Quantum Physics · Physics 2025-04-14 James Fullwood , Arthur J. Parzygnat

Well-controlled quantum systems can potentially be used as quantum simulators. However, a quantum simulator is inevitably perturbed by coupling to additional degrees of freedom. This constitutes a major roadblock to useful quantum…

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…

A generic qubit unitary operator affected by depolarizing noise is duplicated and inserted in a quantum switch process realizing a superposition of causal orders. The characterization of the resulting switched quantum channel is worked out…

Quantum Physics · Physics 2021-04-14 Francois Chapeau-Blondeau

A formalism for quantum error correction based on operator algebras was introduced in [1] via consideration of the Heisenberg picture for quantum dynamics. The resulting theory allows for the correction of hybrid quantum-classical…

Quantum Physics · Physics 2009-11-13 Cedric Beny , Achim Kempf , David W. Kribs