Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

International Symposium on Information Theory and its Applications

Property of capacity by WDM for attenuated quantum channel

Kazuha Ohashi, Tsuyoshi Sasaki Usuda

Published Oct 1, 2012• 0 citations
OpenAlex

Abstract

In 2004, Giovannetti and others gave both the broadband and narrowband channel capacities of an attenuated quantum channel [1]. However, the derived broadband channel capacity is impossible to realize. Therefore, we treat the broadband channel capacity as an upper bound and it is necessary to derive an achievable limit. In a previous work, to show the true capacity, the capacity by wavelength division multiplexing (WDM) was defined and compared with the broadband channel capacity when there is no attenuation [7]. We consider more detailed properties of this WDM capacity and attenuated channels with frequency-dependent loss.

Related papers

On attainment of the capacity of broadband quantum channel by wavelength division multiplexing

Yoshio Takamura, Shogo Usami, Tsuyoshi Sasaki Usuda

Recently, the exact solution of the capacity of an attenuated quantum channel which is a model of a long distance optical fiber channel was derived [V. Giovannetti, et al., Phys. Rev. Lett. 90, 027902, (2004)]. In particular, the capacity of a broadband quantum channel, which is the ultimate limit of quantum communications, was shown. In this paper, we consider wavelength division multiplexing in order to attain the capacity of a broadband quantum channel.

International Symposium on Information Theory and its Applications•Oct 1, 2010•2 citations

Narrow bounds for the quantum capacity of thermal attenuators

Matteo Rosati, Andrea Mari, Vittorio Giovannetti

Thermal attenuator channels model the decoherence of quantum systems interacting with a thermal bath, e.g., a two-level system subject to thermal noise and an electromagnetic signal traveling through a fiber or in free-space. Hence determining the quantum capacity of these channels is an outstanding open problem for quantum computation and communication. Here we derive several upper bounds on the quantum capacity of qubit and bosonic thermal attenuators. We introduce an extended version of such channels which is degradable and hence has a single-letter quantum capacity, bounding that of the original thermal attenuators. Another bound for bosonic attenuators is given by the bottleneck inequality applied to a particular channel decomposition. With respect to previously known bounds we report better results in a broad range of attenuation and noise: we can now approximate the quantum capacity up to a negligible uncertainty for most practical applications, e.g., for low thermal noise.

arXiv:1801.04731•Nature Communications•Oct 12, 2018•60 citations

Broadband channel capacities

Vittorio Giovannetti, Seth Lloyd, Lorenzo Maccone +1 more

We study the communication capacities of bosonic broadband channels in the presence of different sources of noise. In particular we analyze lossy channels in the presence of white noise and thermal bath. In this context, we provide a solution for the entanglement-assisted capacity and upper and lower bounds for the classical and quantum capacities.

arXiv:quant-ph/0307098•Physical Review A•Dec 31, 2003•61 citations

Coexistence of a quantum channel and classical channels in passive optical networks

Xun Wang, Il-Pyeong Hwang, Seung-Hyeon Ahn +1 more

We investigate feasibility of coexistence of a quantum channel and classical channels in a single fiber for passive optical networks (PONs) based on time division multiplexing (TDM) or wavelength division multiplexing (WDM) technologies.

IEEE Photonics Conference•Oct 1, 2015•1 citation

Quantum Detection of Wavelength Division Multiplexing Optical Coherent Signals in Lossy Channels

Atsushi Waseda, Masahide Sasaki, Masahiro Takeoka +3 more

We numerically evaluate the wavelength division multiplexing (WDM) data transmission of coherent phase-shift keying (PSK) and quadrature amplitude modulation (QAM) signals in optical fiber communication and deep-space communication channels with conventional homodyne-based(dyne-type) detections and various quantum detection strategies. We show the quantitative gap between these detection strategies and especially in the quantum-limited region where the quantum noise seriously limits the transmission rate. For an extremely weak signal input power, there is a crucial gap between the capacity limit and the transmission rates of the WDM system with dyne-type detections. We show that this gap is filled by applying a collective square root detection (SRD) only for each channel, not necessary for quantum collective decoding among WDM channels.

International Conference on Availability, Reliability and Security (ARES)•Feb 1, 2010•0 citations

Capacity of optical transmission with attenuation and amplification

Xiaoyu Chen, Li-zhen Jiang, Liang Han

The optical signal transmitted on a fiber with thermal noise, attenuation and amplification is studied. The channel is considered as a quantum channel while the signal to be transmitted is classical. The classical information is encoded in a quantum state then it is transmitted in optical fiber. At the receiving end, measurement is performed on the output quantum state to retrieve the classical information. The optimal distribution of the input quantum state achieving the channel capacity is Gaussian. The capacity is characterized by the attenuation/amplification coefficient and thermal noise in the transmission and at the measurement process together by the power of the input. The loss (or attenuation) of an optical fiber usually should be compensated by the amplification. We show that when they coexist, additional noise occurs

IEEE Information Theory Workshop (ITW)•Oct 1, 2006•0 citations
In 2004, Giovannetti and others gave both the broadband and narrowband channel capacities of an attenuated quantum channel [1]. However, the derived broadband channel capacity is impossible to realize. Therefore, we treat the broadband channel capacity as an upper bound and it is necessary to derive an achievable limit. In a previous work, to show the true capacity, the capacity by wavelength division multiplexing (WDM) was defined and compared with the broadband channel capacity when there is no attenuation [7]. We consider more detailed properties of this WDM capacity and attenuated channels with frequency-dependent loss.
Thermal attenuator channels model the decoherence of quantum systems interacting with a thermal bath, e.g., a two-level system subject to thermal noise and an electromagnetic signal traveling through a fiber or in free-space. Hence determining the quantum capacity of these channels is an outstanding open problem for quantum computation and communication. Here we derive several upper bounds on the quantum capacity of qubit and bosonic thermal attenuators. We introduce an extended version of such channels which is degradable and hence has a single-letter quantum capacity, bounding that of the original thermal attenuators. Another bound for bosonic attenuators is given by the bottleneck inequality applied to a particular channel decomposition. With respect to previously known bounds we report better results in a broad range of attenuation and noise: we can now approximate the quantum capacity up to a negligible uncertainty for most practical applications, e.g., for low thermal noise.
We numerically evaluate the wavelength division multiplexing (WDM) data transmission of coherent phase-shift keying (PSK) and quadrature amplitude modulation (QAM) signals in optical fiber communication and deep-space communication channels with conventional homodyne-based(dyne-type) detections and various quantum detection strategies. We show the quantitative gap between these detection strategies and especially in the quantum-limited region where the quantum noise seriously limits the transmission rate. For an extremely weak signal input power, there is a crucial gap between the capacity limit and the transmission rates of the WDM system with dyne-type detections. We show that this gap is filled by applying a collective square root detection (SRD) only for each channel, not necessary for quantum collective decoding among WDM channels.
The optical signal transmitted on a fiber with thermal noise, attenuation and amplification is studied. The channel is considered as a quantum channel while the signal to be transmitted is classical. The classical information is encoded in a quantum state then it is transmitted in optical fiber. At the receiving end, measurement is performed on the output quantum state to retrieve the classical information. The optimal distribution of the input quantum state achieving the channel capacity is Gaussian. The capacity is characterized by the attenuation/amplification coefficient and thermal noise in the transmission and at the measurement process together by the power of the input. The loss (or attenuation) of an optical fiber usually should be compensated by the amplification. We show that when they coexist, additional noise occurs