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Many different quantum information communication protocols such as teleportation, dense coding and entanglement based quantum key distribution are based on the faithful transmission of entanglement between distant location in an optical…

Quantum processing units boost entanglement at the level of hardware and enable physical simulations of highly correlated electron states in molecules and intermolecular chemical bonds. The variational quantum eigensolver provides a…

We develop a model for a noisy communication channel in which the noise affecting consecutive transmissions is correlated. This model is motivated by fluctuating birefringence of fiber optic links. We analyze the role of entanglement of the…

Quantum Physics · Physics 2009-11-10 Jonathan Ball , Andrzej Dragan , Konrad Banaszek

Unitary errors, such as those arising from fault-tolerant compilation of quantum algorithms, systematically bias observable estimates. Correcting this bias typically requires additional resources, such as an increased number of non-Clifford…

Quantum Physics · Physics 2026-01-13 Dmitrii Khitrin , Kenneth R. Brown , Abhinav Anand

We introduce a hybrid quantum-classical framework for efficiently implementing approximate unitary dilations of non-unitary operators with enhanced noise resilience. The method embeds a target non-unitary operator into a subblock of a…

Quantum Physics · Physics 2025-10-23 S. X. Li , Keren Li , J. B. You , Y. -H. Chen , Clemens Gneiting , Franco Nori , X. Q. Shao

A quantum network is expected to enhance distributed quantum computing and quantum communication over a long distance while providing unconditional security. As quantum entanglement is essential for a quantum network, major issues from…

Two separated observers, by applying local operations to a supply of not-too-impure entangled states ({\em e.g.} singlets shared through a noisy channel), can prepare a smaller number of entangled pairs of arbitrarily high purity ({\em…

Quantum repeaters are critical to the development of quantum networks, enabling rates of entanglement distribution beyond those attainable by direct transmission. We consider multiple continuous-variable, squeezed light-based entanglement…

Quantum Physics · Physics 2023-01-24 Ian J. Tillman , Allison Rubenok , Saikat Guha , Kaushik P. Seshadreesan

A perfect teleportation protocol requires pure maximally shared entangled states. While in reality the shared entanglement is severely degraded due to the inevitable interaction with the noisy environment, which leads to mixed entangled…

Quantum Physics · Physics 2023-04-12 Sajede Harraz , Jiao-Yang Zhang , Shuang Cong

A major challenge in quantum communication is addressing the negative effects of noise on channel capacity, especially for completely depolarizing channels, where information transmission is inherently impossible. The concept of indefinite…

Directing indistinguishable photons from one input port into separate output ports is a fundamental operation in quantum information processing. The simplest scheme for achieving routing beyond random chance uses the photon blockade effect…

Quantum Physics · Physics 2023-05-03 Harjot Singh , Jasvith Raj Basani , Edo Waks

In this paper we introduce a way to quantify the noise level associated to a given quantum transformation. The key mechanism lying at the heart of the proposal is "noise addition": in other words we compute the amount of extra noise we need…

Quantum Physics · Physics 2015-03-20 Antonella De Pasquale , Vittorio Giovannetti

We analyze three quantum communication protocols that have been proposed in the literature, and compare how well they communicate single-rail entanglement. We use specific metrics for output state purity and probability of success and…

Quantum Physics · Physics 2022-12-14 Caroline Mauron , Timothy C. Ralph

The realization of a quantum network node of matter-based qubits compatible with telecom-band operation and large-scale quantum information processing is an outstanding challenge that has limited the potential of elementary quantum…

Quantum Physics · Physics 2021-12-06 William Huie , Shankar G. Menon , Hannes Bernien , Jacob P. Covey

We investigate effective noise channels for encoded quantum systems with and without active error correction. Noise acting on physical qubits forming a logical qubit is thereby described as a logical noise channel acting on the logical…

Quantum Physics · Physics 2013-10-30 Frederik Kesting , Florian Fröwis , Wolfgang Dür

We describe a quantum repeater protocol for long-distance quantum communication. In this scheme, entanglement is created between qubits at intermediate stations of the channel by using a weak dispersive light-matter interaction and…

Quantum Physics · Physics 2009-11-11 P. van Loock , T. D. Ladd , K. Sanaka , F. Yamaguchi , Kae Nemoto , W. J. Munro , Y. Yamamoto

Accurately estimating high-order moments of quantum states is an elementary precondition for many crucial tasks in quantum computing, such as entanglement spectroscopy, entropy estimation, spectrum estimation, and predicting non-linear…

Quantum Physics · Physics 2024-05-16 Benchi Zhao , Mingrui Jing , Lei Zhang , Xuanqiang Zhao , Yu-Ao CHen , Kun Wang , Xin Wang

Quantum hypothesis testing has been greatly advanced for the binary discrimination of two states, or two channels. In this setting, we already know that quantum entanglement can be used to enhance the discrimination of two bosonic channels.…

Quantum Physics · Physics 2020-07-30 Quntao Zhuang , Stefano Pirandola

Unambiguous unitary maps and unambiguous unitary quantum channels are introduced and some of their properties are derived. These properties ensure certain simple form for the measurements involved in realizing an unambiguous unitary quantum…

Quantum Physics · Physics 2008-11-14 Shengjun Wu , Xuemei Chen

We propose using variational quantum algorithms (VQAs) to simulate established quantum algorithms under realistic noise conditions, aiming to surpass the fidelity of theoretical circuits in noisy environments. Focusing on the Quantum…