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Two quantum channels are called compatible if they can be obtained as marginals from a single broadcasting channel; otherwise they are incompatible. We derive a characterization of the compatibility relation in terms of concatenation and…

Quantum Physics · Physics 2017-03-06 Teiko Heinosaari , Takayuki Miyadera

Using the axiomatic definition of the coherence measure, such as the $l_{1}$ norm and the relative entropy, we study the phenomena of two-qubit system quantum coherence through quantum channels where successive uses of the channels are…

Quantum Physics · Physics 2016-12-30 You-neng Guo , Ke Zeng , Qing-long Tian , Zheng-da Li

Quantum phase estimation is a core task in quantum technologies ranging from metrology to quantum computing, where it appears as a key subroutine in various algorithms. Here, we quantitatively connect the performance of phase estimation…

Quantum Physics · Physics 2026-05-11 Felix Ahnefeld , Thomas Theurer , Martin B. Plenio

Much of the discussion of decoherence has been in terms of a particle moving in one dimension that is placed in an initial superposition state (a Schr\"{o}dinger "cat" state) corresponding to two widely separated wave packets. Decoherence…

Quantum Physics · Physics 2007-05-23 M. Murakami , G. W. Ford , R. F. O'Connell

Nonseparability - multipartite states that cannot be factorized - is one of the most striking features of quantum mechanics, as it gives rise to entanglement and non-causal correlations. In quantum computing, it also contributes directly to…

Quantum Physics · Physics 2026-01-07 Mathieu Padlewski , Tim Tuuva , Benjamin Apffel , Hervé Lissek , Romain Fleury

We outline formal and physical similarities between the quantum dynamics of open systems, and the mesoscopic description of classical systems affected by weak noise. The main tool of our interest is the dissipative Wigner equation, that,…

Quantum Physics · Physics 2023-02-27 Domenico Lippolis , Akira Shudo

Starting from the geometric description of quantum systems, we propose a novel approach to time-independet dissipative quantum processes according to which the energy is dissipated but the coherence of the states is preserved. Our proposal…

Quantum Physics · Physics 2021-08-02 Hans Cruz-Prado , Alessandro Bravetti , Angel Garcia-Chung

We propose three core ideas: 1. the wave-particle duality of the qudit quantum space; 2. the classification of all elementary quantum gates by ordered pairs of qudit functionals; 3. a new type of quantum gates called the "quantum wave…

Quantum Physics · Physics 2022-12-22 Zixuan Hu , Sabre Kais

The fundamental dynamics of quantum particles is neutral with respect to the arrow of time. And yet, our experiments are not: we observe quantum systems evolving from the past to the future, but not the other way round. A fundamental…

Quantum Physics · Physics 2022-11-01 Giulio Chiribella , Zixuan Liu

Fundamental limits on communication rates over quantum channels are given by mathematical expressions involving entropic formulas. Often, it is unclear if these expressions are computable. This thesis describes contributions to the study of…

Quantum Physics · Physics 2023-04-28 Mohammad A. Alhejji

The correlation structure of multitime quantum processes - succinctly described by quantum combs - is an important resource for many quantum information protocols and control tasks. Inspired by approaches for quantum states, we introduce…

Quantum Physics · Physics 2025-10-17 Graeme D. Berk , Kavan Modi , Simon Milz

The concept of entanglement fraction is generalized to define coherence fraction of a quantum state. Precisely, it quantifies the proximity of a quantum state to maximally coherent state and it can be used as a measure of coherence.…

Quantum Physics · Physics 2019-06-21 Sumana Karmakar , Ajoy Sen , Indrani Chattopadhyay , Amit Bhar , Debasis Sarkar

Quantum resource theories have been widely studied to systematically characterize the non-classicality of quantum systems. Most resource theories focus on quantum states and study their interconversions. Although quantum channels are…

Quantum Physics · Physics 2020-02-19 Yunchao Liu , Xiao Yuan

We present a framework for quantifying information flow within general quantum processes. For this purpose, we introduce the signaling power of quantum channels and discuss its relevant operational properties. This function supports…

Quantum Physics · Physics 2025-08-08 Leonardo S. V. Santos , Zhen-Peng Xu , Jyrki Piilo , Otfried Gühne

The partial trace operation is usually considered in composite quantum systems, to reduce the state on a single subsystem. This operation has a key role in the decoherence effect and quantum measurements. However, partial trace operations…

Quantum Physics · Physics 2024-03-18 Quentin Ansel

We characterize the behavior of quantum correlations under the influence of local noisy channels. Intuition suggests that such noise should be detrimental for quantumness. When considering qubit systems, we show for which channel this is…

Quantum Physics · Physics 2011-10-18 Alexander Streltsov , Hermann Kampermann , Dagmar Bruß

Estimating the information transmission capability of a quantum channel remains one of the fundamental problems in quantum information processing. In contrast to classical channels, the information-carrying capability of quantum channels is…

Quantum Physics · Physics 2024-07-26 Aditya Nema , Ananda G. Maity , Sergii Strelchuk , David Elkouss

One of the basic distinctions between classical and quantum mechanics is the existence of fundamentally incompatible quantities. Such quantities are present on all levels of quantum objects: states, measurements, quantum channels, and even…

Quantum Physics · Physics 2021-06-16 Erkka Haapasalo , Tristan Kraft , Nikolai Miklin , Roope Uola

We reveal several distinct regimes of the relaxation dynamics of a small quantum system coupled to an environment within the plane of the dissipation strength and the reservoir temperature. This is achieved by discriminating between…

Quantum Physics · Physics 2015-06-17 D. M. Kennes , O. Kashuba , V. Meden

Quantum manifestations of isoperiodic stable structures (QISSs) have a crucial role in the current behavior of quantum dissipative ratchets. In this context, the simple shape of the ISSs has been conjectured to be an almost exclusive…

Quantum Physics · Physics 2015-03-18 Leonardo Ermann , Gabriel G. Carlo
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