English
Related papers

Related papers: Coherence of quantum channels

200 papers

Quantum dots are nanometer-scale semiconductor particles that exhibit size-dependent quantum mechanical properties. In this work, we investigate the dynamics of quantum correlations, quantified by the concurrence and the quantum coherence,…

We characterized unital quantum channels of single photon polarization qubits. The channels are composed of two birefringent crystals and wave-plates, where their decoherence properties are controlled. An experimental comparison between two…

Quantum Physics · Physics 2012-03-16 A. Shaham , H. S. Eisenberg

Quantifying intrinsic irreversibility in open quantum dynamics is central to understanding decoherence and information loss in many-body systems. In this work, we introduce the Choi echo, which provides an operational interpretation of the…

Quantum Physics · Physics 2025-12-15 Jose Alfredo de Leon , Miguel Gonzalez , Carlos Diaz-Mejia

Quantum coherence is a prime resource in quantum computing and quantum communication. Quantum coherence of an arbitrary qubit state can be created at a remote location using maximally entangled state, local operation and classical…

Quantum Physics · Physics 2023-02-09 Jasleen Kaur , Shrobona Bagchi , Arun Kumar Pati

A programmable quantum processor uses the states of a program register to specify one element of a set of quantum channels which is applied to an input register. It is well-known that such a device is impossible with a finite-dimensional…

Quantum Physics · Physics 2021-06-30 Martina Gschwendtner , Andreas Bluhm , Andreas Winter

Estimating the unitarity of an unknown quantum channel $\mathcal{E}$ provides information on how much it is unitary, which is a basic and important problem in quantum device certification and benchmarking. Unitarity estimation can be…

Quantum Physics · Physics 2026-02-23 Kean Chen , Qisheng Wang , Peixun Long , Mingsheng Ying

We present the uncertainty relations in terms of the symmetrized \r{ho}-absolute variance, which generalizes the uncertainty relations for arbitrary operator (not necessarily Hermitian) to quantum channels. By recalling the quantity…

Quantum Physics · Physics 2024-10-16 Cong Xu , Qing-Hua Zhang , Shao-Ming Fei

The peculiar uncertainty or randomness of quantum measurements stems from coherence, whose information-theoretic characterization is currently under investigation. Under the resource theory of coherence, it is interesting to investigate…

Quantum Physics · Physics 2019-10-25 Xiao Yuan , Qi Zhao , Davide Girolami , Xiongfeng Ma

Incompatible quantum channels cannot be jointly and exactly realized, meaning that any approximate joint realization inevitably entails a tradeoff in implementation accuracy. While this notion of channel incompatibility unifies fundamental…

Quantum Physics · Physics 2026-05-13 Shintaro Minagawa , Ryo Takakura , Kensei Torii

In realistic quantum information processing tasks, quantum states are inevitably affected by environmental noise, leading to decoherence and degradation of useful quantum resources. The coherence fraction, which serves as an important…

Quantum Physics · Physics 2026-05-19 Priyabrata Char , Dipayan Chakraborty , Indrani Chattopadhyay , Debasis Sarkar

We consider the problem of separability of quantum channels via the Choi matrix representation given by the Choi-Jamio{\l}kowski isomorphism. We explore three classes of separability across different cuts between systems and ancillae and we…

Quantum Physics · Physics 2020-11-11 Nadia Milazzo , Daniel Braun , Olivier Giraud

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

In this paper we consider decoherence-free communication over multiple access and $k$-user quantum channels. First, we concentrate on a hermitian unitary noise model $U$ for a two-access bi-unitary channel and show that in this case a…

Quantum Physics · Physics 2022-01-03 Maciej Demianowicz

The reliability of quantum channels for transmitting information is of profound importance from the perspective of quantum information. This naturally leads to the question as how well a quantum state is preserved when subjected to a…

Quantum Physics · Physics 2021-01-19 Javid Naikoo , Subhashish Banerjee , R. Srikanth

The quantum channel-state duality permits the characterization of a quantum process through a quantum state, referred to as a Choi state. This characteristic serves as the impetus for the quantum computing paradigm that utilizes Choi states…

Quantum Physics · Physics 2025-04-03 Y. -D. Liu , D. -S. Wang

We introduce a quantity called the coherence of purification which can be a measure of total quantumness for a single system. We prove that coherence of purification is always more than the coherence of the system. For a pure state, the…

Quantum Physics · Physics 2019-07-31 Arun Kumar Pati , Long-Mei Yang , Chiranjib Mukhopadhyay , Shao-Ming Fei , Zhi-Xi Wang

The coexistence of quantum and classical signals over the same optical fiber with minimal degradation of the transmitted quantum information is critical for operating large-scale quantum networks over the existing communications…

We investigate decoherence channels that are modelled as a sequence of collisions of a quantum system (e.g., a qubit) with particles (e.g., qubits) of the environment. We show that collisions induce decoherence when a bi-partite interaction…

Quantum Physics · Physics 2009-11-11 Mario Ziman , Vladimir Buzek

Quantum decoherence due to imperfect manipulation of quantum devices is a key issue in the noisy intermediate-scale quantum (NISQ) era. Standard analyses in quantum information and quantum computation use error rates to parameterize quantum…

Quantum Physics · Physics 2023-02-23 Yuchen Guo , Shuo Yang

We study decoherence of two non-interacting qubits. The environment and its interaction with the qubits are modelled by random matrices. Decoherence, measured in terms of purity, is calculated in linear response approximation. Monte Carlo…

Quantum Physics · Physics 2007-11-22 C. Pineda , T. Gorin , T. H. Seligman