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Quantum coherence characterizes the non-classical feature of a single party system with respect to a local basis. Based on a recently introduced resource framework, coherence can be regarded as a resource and be systematically manipulated…

Quantum Physics · Physics 2018-09-26 Yunchao Liu , Qi Zhao , Xiao Yuan

Quantum mechanics implies that not all physical properties can be simultaneously well defined, such as the momentum and position due to Heisenberg uncertainty principle. Some alternative theories have been explored, notably the…

Quantum Physics · Physics 2012-09-18 Xin-Yu Pan , Yan-Chun Chang , Gang-Qin Liu , Heng Fan

Previous studies in quantum information have recognized that specific types of noise can encode information in certain applications. However, the role of noise in Quantum Hypothesis Testing (QHT), traditionally assumed to undermine…

Quantum Physics · Physics 2024-08-06 Qing Li , Lingna Wang , Min Jiang , Ze Wu , Haidong Yuan , Xinhua Peng

Contextuality is considered as an intrinsic signature of non-classicality, and a crucial resource for achieving unique advantages of quantum information processing. However, recently there have been debates on whether classical fields may…

Quantum Physics · Physics 2019-02-28 Aonan Zhang , Huichao Xu , Jie Xie , Han Zhang , Brian J. Smith , M. S. Kim , Lijian Zhang

On noisy intermediate-scale quantum (NISQ) devices, expectation values of many observables are obtained through sampling-based approximations to trace-like quantities. A central limitation of this approach is destructive cancellation under…

Quantum Physics · Physics 2026-05-06 Myeongsu Kim , Manas Sajjan , Sabre Kais

Recent experiments have shown that nature violates noncontextual inequalities regardless of the state of the physical system. So far, all these inequalities involve measurements of dichotomic observables. We show that state-independent…

Quantum Physics · Physics 2011-04-20 Angel R. Plastino , Adan Cabello

We show that there are Bell-type inequalities for noncontextual theories that are violated by any quantum state. One of these inequalities between the correlations of compatible measurements is particularly suitable for testing this…

Quantum Physics · Physics 2009-07-28 Adan Cabello

In this paper we present an analog of the Bell's inequalities violation test for $N$ qubits to be performed in a nuclear magnetic resonance (NMR) quantum computer. This can be used to simulate or predict results for different Bell's…

Quantum theory features several phenomena which can be considered as resources for information processing tasks. Some of these effects, such as entanglement, arise in a nonlocal scenario, where a quantum state is distributed between…

Quantum Physics · Physics 2024-07-22 Martin Plávala , Otfried Gühne

Measurement scenarios containing events with relations of exclusivity represented by pentagons, heptagons, nonagons, etc., or their complements are the only ones in which quantum probabilities cannot be described classically. Interestingly,…

In quantum information theory, entropic inequalities act as the necessary and sufficient conditions to noncontextuality. Here, we first experimentally demonstrate the violation of the entropic noncontextual inequality in a four-level…

Quantum Physics · Physics 2018-05-24 Suvadeep Roy , Bikash K. Behera , Prasanta K. Panigrahi

In this essay we discuss the issue of quantum information and recent nuclear magnetic resonance (NMR) experiments. We explain why these experiments should be regarded as quantum information processing (QIP) despite the fact that, in present…

Quantum Physics · Physics 2007-05-23 Raymond Laflamme , David G. Cory , Camille Negrevergne , Lorenza Viola

Experimental characterizations of a quantum system involve the measurement of expectation values of observables for a preparable state |psi> of the quantum system. Such expectation values can be measured by repeatedly preparing |psi> and…

Quantum Physics · Physics 2009-11-13 Emanuel Knill , Gerardo Ortiz , Rolando D. Somma

The Kochen-Specker theorem theoretically shows evidence of the incompatibility of noncontextual hidden variable theories with quantum mechanics. Quantum contextuality is a more general concept than quantum non-locality which is quite well…

Quantum Physics · Physics 2010-08-05 Yuji Hasegawa , Katharina Durstberger-Rennhofer , Stephan Sponar , Helmut Rauch

In a noncontextual hidden variable model of quantum theory, hidden variables determine the outcomes of every measurement in a manner that is independent of how the measurement is implemented. Using a generalization of this notion to…

Quantum Physics · Physics 2009-01-09 Robert W. Spekkens , D. H. Buzacott , A. J. Keehn , Ben Toner , G. J. Pryde

We employ the resource theory of generalized contextuality as a tool for analyzing the structure of prepare-and-measure scenarios. We argue that this framework simplifies proofs of quantum contextuality in complex scenarios and strengthens…

Quantum Physics · Physics 2023-11-29 Rafael Wagner , Roberto D. Baldijão , Alisson Tezzin , Bárbara Amaral

We introduce a method for testing quantum correlations in terms of quasiprobability functions in the presence of noise. We analyze the effects of measurement imperfection and thermal environment on quantum correlations and show that their…

Quantum Physics · Physics 2020-07-09 Seung-Woo Lee , Jaewan Kim , Wonmin Son

Nuclear Magnetic Resonance (NMR) has provided a valuable experimental testbed for quantum information processing (QIP). Here, we briefly review the use of nuclear spins as qubits, and discuss the current status of NMR-QIP. Advances in the…

Quantum process tomography is a procedure by which the unknown dynamical evolution of an open quantum system can be fully experimentally characterized. We demonstrate explicitly how this procedure can be implemented with a nuclear magnetic…

Quantum Physics · Physics 2007-05-23 Andrew M. Childs , Isaac L. Chuang , Debbie W. Leung

In this work we investigate how to quantify the coherence of quantum measurements. First, we establish a resource theoretical framework to address the coherence of measurement and show that any statistical distance can be adopted to define…

Quantum Physics · Physics 2020-08-11 Kyunghyun Baek , Adel Sohbi , Jaehak Lee , Jaewan Kim , Hyunchul Nha