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We present a protocol of remote nondestructive parity measurement (RNPM) on a pair of quantum memories. The protocol works as a single module for key operations such as entanglement generation, Bell measurement, parity check measurement,…

Quantum Physics · Physics 2013-05-30 Koji Azuma , Hitoshi Takeda , Masato Koashi , Nobuyuki Imoto

Many quantum information tasks use inputs of the form $\rho^{\otimes m}$, which naturally induce permutation and unitary symmetries. We classify all quantum channels that respect both symmetries - i.e. unitary-equivariant and…

Quantum Physics · Physics 2025-10-10 Laura Mančinska , Elias Theil

Quantum networks offer a unifying set of opportunities and challenges across exciting intellectual and technical frontiers, including for quantum computation, communication, and metrology. The realization of quantum networks composed of…

Quantum Physics · Physics 2009-11-13 H. J. Kimble

This paper combines quantum computation with classical neural network theory to produce a quantum computational learning algorithm. Quantum computation uses microscopic quantum level effects to perform computational tasks and has produced…

Quantum Physics · Physics 2007-05-23 Dan Ventura , Tony Martinez

Recently the theory of communication developed by Shannon has been extended to the quantum realm by exploiting the rules of quantum theory. This latter stems on complex vector spaces. However complex (as well as real) numbers are just…

Information Theory · Computer Science 2018-04-23 Samad Khabbazi Oskouei , Stefano Mancini

We connect two key concepts in quantum information: compatibility and divisibility of quantum channels. Two channels are compatible if they can be both obtained via marginalization from a third channel. A channel divides another channel if…

Quantum Physics · Physics 2022-07-27 Cristhiano Duarte , Lorenzo Catani , Raphael C. Drumond

Any repeated use of a fixed experimental instrument is subject to memory effects. We design an estimation method uncovering the details of the underlying interaction between the system and the internal memory without having any experimental…

Quantum Physics · Physics 2015-10-21 Tomas Rybar , Mario Ziman

A general quantum noisy channel is analyzed, wherein the transmitted qubits may experience symmetry-breaking decoherence, along with memory effects. We find the optimal basis not to be fully entangled, but a combination of factorized and…

Quantum Physics · Physics 2015-05-13 Goren Gordon , Gershon Kurizki

Coherence is a basic notion for quantum states. Instead of quantum states, in this work, We establish a resource theory for quantifying the coherence of Gaussian channels. To do this, we propose the definitions of incoherent Gaussian…

Quantum Physics · Physics 2019-08-15 Jianwei Xu

It is known that the existence of memory effect can revive quantum correlations in open system dynamics. In this regard, the backflow of information from environment to the system can be identified with Complete Positive (CP) indivisibility…

Quantum Physics · Physics 2025-08-27 Anumita Mukhopadhyay , Praggnyamita Ghosh , Shibdas Roy

This paper considers quantum network coding, which is a recent technique that enables quantum information to be sent on complex networks at higher rates than by using straightforward routing strategies. Kobayashi et al. have recently showed…

Quantum Physics · Physics 2015-06-05 Takahiko Satoh , Francois Le Gall , Hiroshi Imai

We study the capacity of a quantum channel where channel acts like controlled phase gate with the control being provided by a one-dimensional quantum spin chain environment. Due to the correlations in the spin chain, we get a quantum…

Quantum Physics · Physics 2017-04-13 Jaideep Mulherkar , V. Sunitha

Conventional wisdom suggests that realistic quantum repeaters will require quasi-deterministic sources of entangled photon pairs. In contrast, we here study a quantum repeater architecture that uses simple parametric down-conversion…

Quantum Physics · Physics 2016-05-24 Hari Krovi , Saikat Guha , Zachary Dutton , Joshua A. Slater , Christoph Simon , Wolfgang Tittel

The universality of a quantum neural network refers to its ability to approximate arbitrary functions and is a theoretical guarantee for its effectiveness. A non-universal neural network could fail in completing the machine learning task.…

Quantum Physics · Physics 2023-06-27 Xiaokai Hou , Guanyu Zhou , Qingyu Li , Shan Jin , Xiaoting Wang

We define here a new kind of quantum channel capacity by extending the concept of zero-error capacity for a noisy quantum channel. The necessary requirement for which a quantum channel has zero-error capacity greater than zero is given.…

Quantum Physics · Physics 2007-05-23 Rex A. C. Medeiros , Francisco M. De Assis

Developing and deploying advanced Quantum Repeater (QR) technologies will be necessary to scale quantum networks to longer distances. Depending on the error mitigation mechanisms adopted to suppress loss and errors, QRs are typically…

Quantum Physics · Physics 2025-12-30 Chuen Hei Chan , Charu Jain , Ezra Kissel , Wenji Wu , Edwin Barnes , Sophia E. Economou , Inder Monga

We investigate the multiple use of a ferromagnetic spin chain for quantum and classical communications without resetting. We find that the memory of the state transmitted during the first use makes the spin chain a qualitatively different…

Quantum Physics · Physics 2009-11-13 A. Bayat , D. Burgarth , S. Mancini , S. Bose

Recursive techniques have recently been introduced into quantum programming so that a variety of large quantum circuits and algorithms can be elegantly and economically programmed. In this paper, we present a proof system for formal…

Quantum Physics · Physics 2024-11-08 Mingsheng Ying , Zhicheng Zhang

We provide a new characterisation of quantum supermaps in terms of an axiom that refers only to sequential and parallel composition. Consequently, we generalize quantum supermaps to arbitrary monoidal categories and operational…

Quantum Physics · Physics 2026-03-11 Matt Wilson , Giulio Chiribella , Aleks Kissinger

Quantum Random Access Memory (QRAM) has the potential to revolutionize the area of quantum computing. QRAM uses quantum computing principles to store and modify quantum or classical data efficiently, greatly accelerating a wide range of…

Quantum Physics · Physics 2023-05-03 Koustubh Phalak , Avimita Chatterjee , Swaroop Ghosh