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Quantum Fisher information (QFI) has potential applications in quantum metrology tasks. We investigate QFI when the consecutive actions of a quantum channel on the sequence of qubits have partial classical correlations. Our results showed…

Quantum Physics · Physics 2020-03-09 Ming-Liang Hu , Hui-Fang Wang

Entanglement behavior for different classes of two qubit systems passing through a generalized amplitude damping channel is discussed. The phenomena of sudden single, double changes and the sudden death of entanglement are reported for…

Quantum Physics · Physics 2015-06-18 Nasser Metwally

We provide a generalization of quantum polar codes to quantum channels with qudit-input, achieving the symmetric coherent information of the channel. Our scheme relies on a channel combining and splitting construction, where a two-qudit…

Quantum Physics · Physics 2025-03-12 Ashutosh Goswami , Mehdi Mhalla , Valentin Savin

We study the entanglement detection by using mutually unbiased measurements and provide a quantum separability criterion that can be experimentally implemented for arbitrary $d$-dimensional bipartite systems. We show that this criterion is…

Quantum Physics · Physics 2015-06-22 Bin Chen , Teng Ma , Shao-Ming Fei

Using the concept of non-degenerate Bell inequality, we show that quantum entanglement, the critical resource for various quantum information processing tasks, can be quantified for any unknown quantum states in a semi-device-independent…

We investigate super dense coding in the presence of noise, i.e. the subsystems of the entangled resource state have to pass a noisy unital quantum channel between the sender and the receiver. We discuss explicitly the case of Pauli…

Quantum Physics · Physics 2015-05-18 Zahra Shadman , Hermann Kampermann , Chiara Macchiavello , Dagmar Bruss

Prior entanglement between sender and receiver, which exactly doubles the classical capacity of a noiseless quantum channel, can increase the classical capacity of some noisy quantum channels by an arbitrarily large constant factor…

Quantum Physics · Physics 2009-01-23 Charles H. Bennett , Peter W. Shor , John A. Smolin , Ashish V. Thapliyal

High-dimensional quantum systems offer a number of advantages in larger information capacity, stronger noise resiliency, higher improved efficiency and accuracy over the qubit systems. In quantum communication the maximally entangled states…

Quantum Physics · Physics 2026-04-15 Si-Qi Du , Guo-Zhu Song , Hai-Rui Wei

This paper continues the study of stochastic maps, or channels, which break entanglement. We give a detailed description of entanglement-breaking qubit channels, and show that such maps are precisely the convex hull of those known as…

Quantum Physics · Physics 2009-11-10 Mary Beth Ruskai

Dense coding is the seminal example of how entanglement can boost qubit communication, from sending one bit to sending two bits. This is made possible by projecting separate particles onto a maximally entangled basis. We investigate more…

We provide a purely quantum version of polar codes, achieving the symmetric coherent information of any qubit-input quantum channel. Our scheme relies on a recursive channel combining and splitting construction, where a two-qubit gate…

Quantum Physics · Physics 2021-05-04 Frédéric Dupuis , Ashutosh Goswami , Mehdi Mhalla , Valentin Savin

Absolutely maximally entangled states are quantum states that exhibit maximal entanglement across any bipartition, making them valuable for applications. This study investigates the behavior of qubit AME states under the influence of noisy…

Quantum Physics · Physics 2025-05-13 Maria Stawska , Jan Wójcik , Andrzej Grudka , Antoni Wójcik

Higher-dimensional entanglement is a valuable resource for several quantum information processing tasks, and is often characterized by the Schmidt number and specific classes of entangled states beyond qubit-qubit and qubit-qutrit systems.…

Quantum Physics · Physics 2025-07-28 Bivas Mallick , Ananda G. Maity , Nirman Ganguly , A. S. Majumdar

We solve the problem of discriminating with minimum error probability two given Pauli channels. We show that, differently from the case of discrimination between unitary transformations, the use of entanglement with an ancillary system can…

Quantum Physics · Physics 2009-11-11 Massimiliano F. Sacchi

Entanglement is essential to many quantum information applications, but it is easily destroyed by quantum decoherence arising from interaction with the environment. We report the first experimental demonstration of an entanglement-based…

Quantum Physics · Physics 2015-06-15 Zheshen Zhang , Maria Tengner , Tian Zhong , Franco N. C. Wong , Jeffrey H. Shapiro

The development of key devices and systems in quantum information technology, such as entangled particle sources, quantum gates and quantum cryptographic systems, requires a reliable and well-established method for characterizing how well…

We fully characterize bipartite entanglement-annihilating (EA) channels that destroy entanglement of any state shared by subsystems and, thus, should be avoided in any entanglement-enabled experiment. Our approach relies on extending the…

Quantum Physics · Physics 2013-09-17 S. N. Filippov , M. Ziman

One of the most fascinating aspects of quantum networks is their capability to distribute entanglement as a nonlocal communication resource. In a first step, this requires network-ready devices that can generate and store entangled states.…

Quantum channel discrimination is a fundamental task in quantum information processing. In the one-shot regime, discrimination between two candidate channels is characterized by the diamond norm. Beyond this basic setting, however, many…

Quantum Physics · Physics 2026-03-13 Chengkai Zhu , Shuyu He , Gereon Koßmann , Xin Wang

We prove that every entangled state is useful as a resource for the problem of minimum-error channel discrimination. More specifically, given a single copy of an arbitrary bipartite entangled state, it holds that there is an instance of a…

Quantum Physics · Physics 2009-07-17 M. Piani , J. Watrous