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We give strong evidence that divisibility of qubit quantum processes implies temporal Tsirelson's bound. We also give strong evidence that the classical bound of the temporal Bell's inequality holds for dynamics that can be described by…

Quantum Physics · Physics 2017-01-10 Thao Le , Felix A. Pollock , Tomasz Paterek , Mauro Paternostro , Kavan Modi

We give a short proof that the coherent information is an achievable rate for the transmission of quantum information through a noisy quantum channel. Our method is to produce random codes by performing a unitarily covariant projective…

Quantum Physics · Physics 2016-11-17 Patrick Hayden , Michal Horodecki , Andreas Winter , Jon Yard

We study the properties of error correcting codes for noise models in the presence of asymmetries and/or correlations by means of the entanglement fidelity and the code entropy. First, we consider a dephasing Markovian memory channel and…

Quantum Physics · Physics 2015-03-17 C. Cafaro , S. L'Innocente , C. Lupo , S. Mancini

We give a criterion to differentiate between dissipative and diffusive quantum operations. It is based on the classical idea that dissipative processes contract volumes in phase space. We define a quantity that can be regarded as ``quantum…

Quantum Physics · Physics 2010-03-31 Ignacio Garcia-Mata , Marcos Saraceno , Maria Elena Spina , Gabriel Carlo

This work investigates the application of quantum machine learning techniques for classical and quantum communication across different qubit channel models. By employing parameterized quantum circuits and a flexible channel noise model, we…

Quantum Physics · Physics 2023-07-14 Lakshika Rathi , Stephen DiAdamo , Alireza Shabani

Quantum error correction assisted by entanglement helps to transmit the encoded qudits through quantum channels with some of them being noiseless. Here we consider a more realistic scheme for experiments what we called as partial-noisy…

Quantum Physics · Physics 2012-09-03 Zhuo Wang , Sixia Yu , Heng Fan , C. H. Oh

Quantum incompatibility, referred as the phenomenon that some quantum measurements cannot be performed simultaneously, is necessary for various quantum information processing tasks, such as nonlocality and steering. When these applications…

Quantum Physics · Physics 2024-11-19 Xiaolin Zhang , Rui Qu , Zehong Chang , Yunlong Wang , Zhenyu Guo , Min An , Hong Gao , Fuli Li , Pei Zhang

We prove a simple inequality for a sum of squares of norms of two vectors in an inner product space. Next, using this inequality we derive the so--called "reverse uncertainty relation" and analyze its properties.

Quantum Physics · Physics 2026-05-28 K. Urbanowski

A recent general model of entanglement, [5], that goes much beyond the usual one based on tensor products of vector spaces is further developed here. It is shown that the usual Cartesian product can be seen as two extreme particular…

General Physics · Physics 2008-07-10 Elemer E Rosinger

The active stabilization of polarization channels is a task of growing importance as quantum networks move to deployed demonstrations over existing fiber infrastructure. However, the uniquely strict requirements for high-fidelity qubit…

Superposition is the core feature that sets quantum theory apart from classical physics. Here, we investigate whether sets of quantum measurements can be modelled by using only devices that are operationally classical, in the sense that…

Quantum Physics · Physics 2026-03-30 Gabriele Cobucci , Alexander Bernal , Roope Uola , Armin Tavakoli

Quantum queue-channels arise naturally in the context of buffering in quantum networks, wherein the noise suffered by the quantum states depends on the time spent waiting in the buffer. It has been shown that the upper-bound on the…

For a continuous-input-continuous-output arbitrarily distributed quantum channel carrying classical information, the channel capacity can be computed in terms of the distribution of the channel envelope, received signal strength over a…

Information Theory · Computer Science 2022-06-09 Mouli Chakraborty , Harun Siljak , Indrakshi Dey , Nicola Marchetti

The method of complementary channel for analysis of reversibility (sufficiency) of a quantum channel with respect to families of input states (pure states for the most part) are considered and applied to Bosonic linear (quasi-free)…

Quantum Physics · Physics 2013-11-12 M. E. Shirokov

Real global-scale quantum communications and quantum key distribution systems cannot be implemented by the current fiber and free-space links. These links have high attenuation, low polarization-preserving capability or extreme sensitivity…

Quantum Physics · Physics 2016-11-17 Laszlo Gyongyosi , Sandor Imre

The theory of quantum error correction is a cornerstone of quantum information processing. It shows that quantum data can be protected against decoherence effects, which otherwise would render many of the new quantum applications…

Quantum Physics · Physics 2009-11-07 M. Keyl , R. F. Werner

We study the phenomenon of quantum backflow in tight-binding systems with complex couplings, considering different boundary conditions and lattice sizes. Backflow is an intrinsically non-classical effect where the density flux associated…

Quantum Physics · Physics 2026-03-11 Francisco Ricardo Torres Arvizu , Adrián Ortega , Hernán Larralde

A quantum error correcting protocol can be substantially improved by taking into account features of the physical noise process. We present an efficient decoder for the surface code which can account for general noise features, including…

Quantum Physics · Physics 2018-06-13 Andrew S. Darmawan , David Poulin

We examine the use of noiseless subsystems for quantum information processing between two parties who do not share a common reference frame. In particular we focus on Bell inequalities in curved spaces and outline a theoretical procedure to…

Quantum Physics · Physics 2007-05-23 Jonathan L. Ball

We review recent results on the simulation of quantum channels, the reduction of adaptive protocols (teleportation stretching), and the derivation of converse bounds for quantum and private communication, as established in PLOB [Pirandola,…

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