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We consider a joint communication and sensing problem over an optical link in which a low-power transmitter simultaneously communicates with a receiver and identifies the range of a defect producing a backscattered signal. We model the…

Quantum Physics · Physics 2026-05-19 Tuna Erdoğan , Shi-Yuan Wang , Shang-Jen Su , Matthieu Bloch

Driven by the demands of high-frequency wireless communications in 5G and 6G systems (e.g., mmWave, sub-THz), we explore a state-dependent {\em Gaussian beam-pointing} (GBP) channel. In this model, the channel state defines an unknown angle…

Information Theory · Computer Science 2025-08-29 Siyao Li , Shuangyang Li , Giuseppe Caire

A complete degradability analysis of one-mode Gaussian Bosonic channels is presented. We show that apart from the class of channels which are unitarily equivalent to the channels with additive classical noise, these maps can be…

Quantum Physics · Physics 2009-11-13 F. Caruso , V. Giovannetti , A. S. Holevo

Although many quantum channels satisfy Completely Positive Trace Preserving (CPTP) condition, there are valid quantum channels that can be non-completely positive (NCP). As memory effects can provide advantages in the dynamics of noisy…

Quantum Physics · Physics 2026-02-18 Anumita Mukhopadhyay , Praggnyamita Ghosh , Shibdas Roy

Noisy teleportation of nonclassical quantum states via a two-mode squeezed-vacuum state is studied with the completely positive map and the Glauber-Sudarshan $P$-function. Using the nonclassical depth as a measure of transmission…

Quantum Physics · Physics 2009-11-07 Masahiro Takeoka , Masashi Ban , Masahide Sasaki

Optical systems are a main platform for quantum information processing. A main challenge is information loss due to scattering in unmonitored modes. These losses are modeled as state-independent beam-splitter interactions, with a thermal…

Quantum Physics · Physics 2026-05-27 Jinyan Chen , Minjeong Song , Jared Jia Xuan Chan , Valerio Scarani

Decoherence errors arising from noisy environments remain a central obstacle to progress in quantum computation and information processing. Quantum error correction (QEC) based on the Gottesman-Kitaev-Preskill (GKP) protocol offers a…

We consider the problem of estimating unknown transmittance $\theta$ of a target bathed in thermal background light. As quantum estimation theory yields the fundamental limits, we employ the lossy thermal-noise bosonic channel model, which…

Quantum Physics · Physics 2022-12-29 Zihao Gong , Nathaniel Rodriguez , Christos N. Gagatsos , Saikat Guha , Boulat A. Bash

In this paper we propose a scheme for quasi-perfect state transfer in a network of dissipative harmonic oscillators. We consider ideal sender and receiver oscillators connected by a chain of nonideal transmitter oscillators coupled by…

Quantum Physics · Physics 2015-05-13 A. Cacheffo , M. A. de Ponte , M. H. Y. Moussa , A. S. M. de Castro

A generic quantum channel can be represented in terms of a unitary interaction between the information-carrying system and a noisy environment. Here, the minimal number of quantum Gaussian environmental modes required to provide a unitary…

Quantum Physics · Physics 2015-05-19 Filippo Caruso , Jens Eisert , Vittorio Giovannetti , Alexander S. Holevo

Quantum teleportation uses a shared entangled resource, local operations, and a digitally error-corrected classical channel to transfer quantum states between distant parties. We introduce a hybrid teleportation-direct transmission protocol…

Quantum Physics · Physics 2026-03-13 Uesli Alushi , Simone Felicetti , Roberto Di Candia

Gaussian channel simulation is an essential paradigm in understanding the evolution of bosonic quantum states. It allows us to investigate how such states are influenced by the environment and how they transmit quantum information. This…

We investigate a quantum coding for quantum communication over a PD (partially degradable) degradable quantum channel. For a PD channel, the degraded environment state can be expressed from the channel output state up to a degrading map. PD…

Quantum Physics · Physics 2016-11-18 Laszlo Gyongyosi

We consider quantum key distribution (QKD) and entanglement distribution using a single-sender multiple-receiver pure-loss bosonic broadcast channel. We determine the unconstrained capacity region for the distillation of bipartite…

Quantum Physics · Physics 2018-03-13 Masahiro Takeoka , Kaushik P. Seshadreesan , Mark M. Wilde

Determining whether a noisy quantum channel can be used to reliably transmit quantum information at a non-zero rate is a challenging problem in quantum information theory. This is because it requires computation of the channel's coherent…

Quantum Physics · Physics 2024-10-24 Satvik Singh , Nilanjana Datta

The notion of weak-degradability of quantum channels is introduced by generalizing the degradability definition given by Devetak and Shor. Exploiting the unitary equivalence with beam-splitter/amplifier channels we then prove that a large…

Quantum Physics · Physics 2007-05-23 Filippo Caruso , Vittorio Giovannetti

We consider imperfect two-mode bosonic quantum transducers that cannot completely transfer an initial source-system quantum state due to insufficient coupling strength or other non-idealities. We show that such transducers can generically…

Quantum Physics · Physics 2019-04-25 Hoi-Kwan Lau , Aashish A. Clerk

Bosonic quantum error correction enables hardware-efficient protection of quantum information by encoding logical qubits in harmonic oscillators. Bosonic grid states, such as Gottesman-Kitaev-Preskill (GKP) states, are particularly…

Local update recovery seeks to maintain quantum information by applying local correction maps alternating with and compensating for the action of noise. Motivated by recent constructions based on quantum LDPC codes in the finite-dimensional…

Quantum Physics · Physics 2023-09-29 Robert König , Cambyse Rouzé

The central issue in this article is to transmit a quantum state in such a way that after some decoherence occurs, most of the information can be restored by a suitable decoding operation. For this purpose, we incorporate redundancy by…

Quantum Physics · Physics 2007-05-23 Bernhard G. Bodmann , David W. Kribs , Vern I. Paulsen