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With increasing communication rates via quantum channels, memory effects become unavoidable whenever the use rate of the channel is comparable to the typical relaxation time of the channel environment. We introduce a model of a bosonic…

Quantum Physics · Physics 2015-03-17 Cosmo Lupo , Vittorio Giovannetti , Stefano Mancini

Quantum memories are a crucial precondition in many protocols for processing quantum information. A fundamental problem that illustrates this statement is given by the task of channel discrimination, in which an unknown channel drawn from a…

Quantum Physics · Physics 2026-01-28 Ties-A. Ohst , Shijun Zhang , Hai Chau Nguyen , Martin Plávala , Marco Túlio Quintino

Environmental effects on the transmission of a state result, in general, in a change in the information carried by it. To mitigate this, many techniques such as quantum error--correcting codes, decoherence--free--subspaces [Rev Mod Phys,…

Quantum Physics · Physics 2021-11-29 Rajni Bala , V. Ravishankar

Quantum memories are regarded as one of the fundamental building blocks of linear-optical quantum computation and long-distance quantum communication. A long standing goal to realize scalable quantum information processing is to build a…

Quantum walks are an analog of classical random walks in quantum systems. Quantum walks have smaller hitting times compared to classical random walks on certain types of graphs, leading to a quantum advantage of quantum-walks-based…

Quantum Physics · Physics 2022-01-21 D. V. Babukhin , W. V. Pogosov

Quantum signal processing (QSP) provides a systematic framework for implementing a polynomial transformation of a linear operator, and unifies nearly all known quantum algorithms. In parallel, recent works have developed randomized…

Quantum Physics · Physics 2025-03-26 John M. Martyn , Patrick Rall

Single photons are the flying qubits of choice for distributing entanglement in a quantum internet. Quantum memories embedded in quantum repeaters are crucial to overcome transmission loss and enhance the rate of quantum communication. A…

Quantum Physics · Physics 2026-03-03 H. -X Luo , C. Li , J. -L. Ren , Y. Yuan , Y. -L. Wen , J. -F. Li , Y. -F. Wang , S. -C. Zhang , H. Yan , S. -L. Zhu

Quantum operations, or quantum channels cannot be inverted in general. An arbitrary state passing through a quantum channel looses its fidelity with the input. Given a quantum channel ${\cal E}$, we introduce the concept of its…

Quantum Physics · Physics 2020-03-25 Vahid Karimipour , Fabio Benatti , Roberto Floreanini

Quantum state tomography (QST) is an essential technique for characterizing quantum states. However, practical implementations of QST are significantly challenged by factors such as shot noise, attenuation, and Raman scattering, especially…

Quantum Physics · Physics 2024-11-26 Artur Czerwinski

Unital quantum channels, defined by their property of leaving the maximally mixed state invariant, form an important class of quantum operations. A distinguished subset of these channels can be represented as a probabilistic mixture of…

Quantum Physics · Physics 2026-03-19 Charlotte Bäcker , Konstantin Beyer , Walter T. Strunz

Quantum teleportation channels can overcome the effects of photonic loss, a major challenge in the implementation of a quantum network over fiber. Teleportation channels are created by distributing an entangled state between two nodes which…

Quantum Physics · Physics 2022-05-16 Aparimit Chandra , Wenhan Dai , Don Towsley

The notion of forgetfulness, used in discrete quantum memory channels, is slightly weakened in order to be applied to the case of continuous channels. This is done in the context of quantum memory channels with Markovian noise. As a case…

Quantum Physics · Physics 2009-10-28 Cosmo Lupo , Laleh Memarzadeh , Stefano Mancini

Quantum-speed-limit (QSL) time captures the intrinsic minimal time interval for a quantum system evolving from an initial state to a target state. In single qubit open systems, it was found that the memory (non-Markovian) effect of…

Quantum Physics · Physics 2015-03-18 Chen Liu , Zhen-Yu Xu , Shiqun Zhu

High-performance quantum memory for quantized states of light is a prerequisite building block of quantum information technology. Despite great progresses of optical quantum memories based on interactions of light and atoms, physical…

Quantum Physics · Physics 2022-06-20 Lixia Ma , Xing Lei , Jieli Yan , Ruiyang Li , Ting Chai , Zhihui Yan , Xiaojun Jia , Changde Xie , Kunchi Peng

Memory is the fundamental form of temporal complexity: when present but uncontrollable, it manifests as non-Markovian noise; conversely, if controllable, memory can be a powerful resource for information processing. Memory effects arise…

Quantum Physics · Physics 2024-05-07 Philip Taranto , Marco Túlio Quintino , Mio Murao , Simon Milz

We consider the transfer of quantum information down a single-mode quantum transmission line. Such quantum channel is modeled as a damped harmonic oscillator, the interaction between the information carriers -a train of N qubits- and the…

Quantum Physics · Physics 2009-09-04 G. Benenti , A. D'Arrigo , G. Falci

Transferring quantum information between two qubits is a basic requirement for many applications in quantum communication and quantum information processing. In the iterative quantum state transfer (IQST) proposed by D. Burgarth et al.…

Quantum Physics · Physics 2007-07-18 Jingfu Zhang , Nageswaran Rajendran , Xinhua Peng , Dieter Suter

In the measurement of a continuous observable Q, the pure components of the reduced state do, in general, depend on the initial state. For measurements which attempt to localize the measured system in a certain region R, the localized wave…

High Energy Physics - Phenomenology · Physics 2007-05-23 Kai J. Druhl

Quantum memory -- the capacity to store and faithfully recover unknown quantum states -- is essential for quantum-enhanced technology. There is thus a pressing need for operationally meaningful means to benchmark candidate memories across…

Quantum Physics · Physics 2021-07-23 Xiao Yuan , Yunchao Liu , Qi Zhao , Bartosz Regula , Jayne Thompson , Mile Gu

In this article we treat the subject of chaotic environments with few degrees of freedom in quantum communication by investigating a conservative dynamical map as a model of a dephasing quantum channel. When the channel's dynamics is…

Quantum Physics · Physics 2010-06-28 Gabriela Barreto Lemos , Giuliano Benenti