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Different approaches in quantifying environmentally-induced decoherence are considered. We identify a measure of decoherence, derived from the density matrix of the system of interest, that quantifies the environmentally induced error,…

Mesoscale and Nanoscale Physics · Physics 2010-10-12 Arkady Fedorov , Leonid Fedichkin , Vladimir Privman

Coherence is a basic notion for quantum states. Instead of quantum states, in this work, We establish a resource theory for quantifying the coherence of Gaussian channels. To do this, we propose the definitions of incoherent Gaussian…

Quantum Physics · Physics 2019-08-15 Jianwei Xu

The effects of the measurement apparatus on quantum coherence are studied by considering a purely dephasing model of a qubit. The initial state is prepared from a thermal state of the whole system by performing a nonselective measurement on…

Quantum Physics · Physics 2021-12-22 Filippo Giraldi

Coherence is a fundamental resource in quantum information processing, which can be certified by a coherence witness. Due to the imperfection of measurement devices, a conventional coherence witness may lead to fallacious results. We show…

Quantum Physics · Physics 2019-08-30 You-Qi Nie , Hongyi Zhou , Jian-Yu Guan , Qiang Zhang , Xiongfeng Ma , Jun Zhang , Jian-Wei Pan

Quantum addition channels have been recently introduced in the context of deriving entropic power inequalities for finite dimensional quantum systems. We prove a reverse entropy power equality which can be used to analytically prove an…

Quantum Physics · Physics 2026-04-13 Chiranjib Mukhopadhyay , Arun Kumar Pati , Sk Sazim

This paper studies the quantification and structural properties of quantum average correlation based on average coherence. Motivated by two mathematically equivalent approaches to define average coherence: one by averaging over complete…

Quantum Physics · Physics 2026-04-28 Xiaoyu Ma , Qing-Hua Zhang , Cong Xu

The coherence power of a quantum channel, that is, its ability to increase the coherence of input states, is a fundamental concept within the framework of the resource theory of coherence. In this note we discuss various possible…

Quantum Physics · Physics 2016-12-23 M. García-Díaz , D. Egloff , M. B. Plenio

We formulate the Frobenius-norm-based measures for quantum coherence and asymmetry respectively. In contrast to the resource theory of coherence and asymmetry, we construct a natural measure of quantum coherence inspired from optical…

Quantum Physics · Physics 2016-08-31 Yao Yao , G. H. Dong , Xing Xiao , C. P. Sun

Quantum decoherence refers to the phenomenon when the interaction of a quantum system with its environment results in the degradation of quantum coherence. Decoherence is considered to be the most popular mechanism responsible for the…

Quantum Physics · Physics 2026-02-25 Mohd Shoaib Qureshi , Tabish Qureshi

Accurate methods of assessing the performance of quantum gates are extremely important. Quantum process tomography and randomized benchmarking are the current favored methods. Quantum process tomography gives detailed information, but…

Quantum Physics · Physics 2014-05-08 Austin G. Fowler , D. Sank , J. Kelly , R. Barends , John M. Martinis

The sensitivity of quantum systems to external disturbances is a fundamental problem for the implementation of functional quantum devices, quantum information and computation. Based on remarkable experimental progress in optics and…

Quantum Physics · Physics 2021-04-21 A. R. C. Buarque , W. S. Dias

Quantum coherence is an important quantum resource which plays a pivotal role in the field of quantum information. Based on metric adjusted skew information, we define a measure of quantum uncertainty to study average coherence under…

Quantum Physics · Physics 2026-04-23 Baolong Cheng , Linlin Ye , Zhaoqi Wu

How to manage coherence as a continuous variable quantum resource is still an open question. We face this situation from the very definition of incoherent states in quadrature basis. We apply several measures of coherence for some physical…

Quantum Physics · Physics 2023-07-18 Laura Ares , Alfredo Luis

Coherence arises from the superposition principle and plays a key role in quantum mechanics. Recently, Baumgratz et al. [T. Baumgratz, M. Cramer, and M. B. Plenio, Phys. Rev. Lett. 113, 140401 (2014)] established a rigorous framework for…

Quantum Physics · Physics 2016-03-23 Jianwei Xu

Overcoming the influence of noise and imperfections in quantum devices is one of the main challenges for viable quantum applications. In this article, we present different protocols, which we denote as "superposed quantum error mitigation",…

Single-photon routers in cavity and circuit QED direct photons by the qubit's energy eigenstate -- a projective decision that destroys coherence. We propose a different primitive: coherence-gated routing, where the decision depends on the…

Quantum Physics · Physics 2026-05-20 Priyank Singh

Quantum reservoir computing offers a promising approach to the utilization of complex quantum dynamics in machine learning. Statistical noise inevitably arises in real settings of quantum reservoir computing (QRC) due to the practical…

Quantum Physics · Physics 2026-04-23 Youssef Kora , Christoph Simon

The fluctuations of electrical current provide information on the dynamics of electrons in quantum devices. Understanding the nature of these fluctuations in a quantum dot is thus a crucial step insofar as this system is the elementary…

Mesoscale and Nanoscale Physics · Physics 2018-10-08 A. Crépieux , S. Sahoo , T. Q. Duong , R. Zamoum , M. Lavagna

With improved gate calibrations reducing unitary errors, we achieve a benchmarked single-qubit gate fidelity of 99.95% with superconducting qubits in a circuit quantum electrodynamics system. We present a method for distinguishing between…

Quantum Physics · Physics 2016-01-13 Sarah Sheldon , Lev S. Bishop , Easwar Magesan , Stefan Filipp , Jerry M. Chow , Jay M. Gambetta

Motivated by the gate set tomography we study quantum channels from the perspective of information which is invariant with respect to the gauge realized through similarity of matrices representing channel superoperators. We thus use the…

Quantum Physics · Physics 2018-04-13 Łukasz Rudnicki , Zbigniew Puchała , Karol Zyczkowski