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

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE

Informational geometric analysis of superactivation of asymptotic quantum capacity of zero-capacity optical quantum channels

László Gyöngyösi, Sándor Imre

Published Feb 10, 2011• 6 citations
Publisher

Abstract

The superactivation of zero-capacity optical quantum channels makes it possible to use two zero-capacity optical quantum channels with a positive joint capacity at the output. Currently, we have no theoretical results for describing all possible combinations of superactive zero-capacity channels, hence there should be many other possible combinations. This paper shows a fundamentally new method of finding the conditions for the superactivation of the asymptotic Lloyd-Shor-Devetak (LSD) channel capacity of zero-capacity optical quantum channels. We introduce a new geometrical representation, called the quantum informational superball representation. Our method provides a fundamentally new and efficient algorithmic solution for discovering all possible superactive channels and it can be applied to analyze the capacity of these channels.

DOI
10.1117/12.874185

Related papers

Information geometric superactivation of classical zero-error capacity of quantum channels

László Gyöngyösi, Sándor Imre

This paper introduces a fundamentally new method of finding the conditions for the superactivation of the zero-error capacity of quantum channels.The zero-error capacity of the quantum channel describes the amount of information which can be transmitted perfectly through a noisy quantum channel.The superactivation of the zero-error capacity of quantum channels makes it possible to use two quantum channels, each with zero zero-error capacity, with a positive joint zero-error capacity.Currently we have no theoretical background for describing all possible combinations of superactive quantum channels, hence there should be many other possible combinations.We give an algorithmic solution to the problem.To analyze the superactivation of the zero-error capacity, we introduce a new geometrical representation, called the quantum superball.Our method can be the first efficient algorithmic solution to discover the still unknown combinations to determine the superactivation of the zero-error capacity of quantum channels, without the extremely high computational costs.

Progress in Informatics•Mar 1, 2011•6 citations

Information Geometric Superactivation of Asymptotic Quantum Capacity and Classical Zero-Error Capacity of Zero-Capacity Quantum Channels

László Gyöngyösi

The superactivation of zero-capacity quantum channels makes it possible to use two zero-capacity quantum channels with a positive joint capacity at the output. Currently, we have no theoretical background for describing all possible combinations of superactive zero-capacity channels; hence, there may be many other possible combinations. In this PhD Thesis I provide an algorithmic solution to the problem of superactivation and prove that superactivation effect is rooted in information geometric issues.

arXiv:1206.5980•Jun 25, 2012•6 citations

Onset of superactivation of quantum capacity

Marco Parentin, Bjarne Bergh, Nilanjana Datta +1 more

Superactivation of quantum capacity is the phenomenon whereby two quantum channels, each with zero quantum capacity, can exhibit a strictly positive capacity when used in tandem. In this work, we explore superactivation in the previously unexplored non-asymptotic regime of finitely many channel uses. We give a definition of finite-blocklength superactivation and propose numerical methods that can certify it. Then, focusing on the 50% erasure and positive-partial-transpose channels considered in the original work on superactivation, we show that as few as 17 uses of the joint channel already enable qubit transmission with a fidelity unattainable by any number of uses of either channel alone, demonstrating a strong finite-blocklength form of superactivation and opening the door to experimental demonstration.

quant-pharXiv:2604.27042•Apr 30, 2026•0 citations

Algorithmic solution to superactivation of zero-capacity optical quantum channels

László Gyöngyösi, Sándor Imre

The superactivation of zero-capacity quantum channels makes it possible to use two zero-capacity quantum channels with a positive joint capacity at the output. Currently, we have no theoretical results for describing all possible combinations of superactive zero-capacity channels, hence there should be many possible - still undiscovered - combinations. Our method gives an algorithmic solution to the superactivation problem, and provides an efficient algorithmic solution for discovering “superactive” zero-capacity optical quantum channels. We analyze the superactivation property of the amplitude damping quantum channel model. This model has great importance in practical communications, since this channel model describes energy dissipation due to the noise of the optical channel. To discover these superactive zero-capacity channels, an extremely large set of possible quantum states has to be analyzed, however an efficient algorithmic framework is still missing for this purpose. We show a fundamentally new method of finding the conditions for “superactive” zero-capacity optical quantum channels.

Photonics Global Conference•Jan 1, 2010•1 citation

An Extreme form of Superactivation for Quantum Zero-Error Capacities

Toby S. Cubitt, Graeme Smith

The zero-error capacity of a channel is the rate at which it can send information perfectly, with zero probability of error, and has long been studied in classical information theory. We show that the zero-error capacity of quantum channels exhibits an extreme form of non-additivity, one which is not possible for classical channels, or even for the usual capacities of quantum channels. By combining probabilistic arguments with algebraic geometry, we prove that there exist channels E1 and E2 with no zero-error classical capacity whatsoever, C_0(E1) = C_0(E2) = 0, but whose joint zero-error quantum capacity is positive, Q_0(E1 x E2) >= 1. This striking effect is an extreme from of the superactivation phenomenon, as it implies that both the classical and quantum zero-error capacities of these channels can be superactivated simultaneously, whilst being a strictly stronger property of capacities. Superactivation of the quantum zero-error capacity was not previously known.

arXiv:0912.2737•Dec 14, 2009•1 citation

Long-distance quantum communications with superactivated Gaussian optical quantum channels

László Gyöngyösi, Sandor Imre

The superactivation of zero-capacity optical quantum channels makes it possible to use two zero-capacity optical quantum channels, with a positive joint capacity at the output. Here we show, that noisy Gaussian quantum channels with the help of entanglement and coherent optical devices, can be used to transmit quantum information perfectly. It will be demonstrated that using the superactivation effect, it is possible to develop efficient quantum repeaters with the elimination of the very inefficient and expensive purification process.

Optical Engineering•Feb 6, 2012•4 citations
The superactivation of zero-capacity optical quantum channels makes it possible to use two zero-capacity optical
quantum channels with a positive joint capacity at the output. Currently, we have no theoretical results for describing all
possible combinations of superactive zero-capacity channels, hence there should be many other possible combinations.
This paper shows a fundamentally new method of finding the conditions for the superactivation of the asymptotic Lloyd-Shor-Devetak (LSD) channel capacity of zero-capacity optical quantum channels. We introduce a new geometrical
representation, called the quantum informational superball representation. Our method provides a fundamentally new
and efficient algorithmic solution for discovering all possible superactive channels and it can be applied to analyze the
capacity of these channels.
This paper introduces a fundamentally new method of finding the conditions for the superactivation of the zero-error capacity of quantum channels.The zero-error capacity of the quantum channel describes the amount of information which can be transmitted perfectly through a noisy quantum channel.The superactivation of the zero-error capacity of quantum channels makes it possible to use two quantum channels, each with zero zero-error capacity, with a positive joint zero-error capacity.Currently we have no theoretical background for describing all possible combinations of superactive quantum channels, hence there should be many other possible combinations.We give an algorithmic solution to the problem.To analyze the superactivation of the zero-error capacity, we introduce a new geometrical representation, called the quantum superball.Our method can be the first efficient algorithmic solution to discover the still unknown combinations to determine the superactivation of the zero-error capacity of quantum channels, without the extremely high computational costs.
The superactivation of zero-capacity quantum channels makes it possible to use two zero-capacity quantum channels with a positive joint capacity at the output. Currently, we have no theoretical background for describing all possible combinations of superactive zero-capacity channels; hence, there may be many other possible combinations. In this PhD Thesis I provide an algorithmic solution to the problem of superactivation and prove that superactivation effect is rooted in information geometric issues.
Superactivation of quantum capacity is the phenomenon whereby two quantum channels, each with zero quantum capacity, can exhibit a strictly positive capacity when used in tandem. In this work, we explore superactivation in the previously unexplored non-asymptotic regime of finitely many channel uses. We give a definition of finite-blocklength superactivation and propose numerical methods that can certify it. Then, focusing on the 50% erasure and positive-partial-transpose channels considered in the original work on superactivation, we show that as few as 17 uses of the joint channel already enable qubit transmission with a fidelity unattainable by any number of uses of either channel alone, demonstrating a strong finite-blocklength form of superactivation and opening the door to experimental demonstration.
The superactivation of zero-capacity quantum channels makes it possible to use two zero-capacity quantum channels with a positive joint capacity at the output. Currently, we have no theoretical results for describing all possible combinations of superactive zero-capacity channels, hence there should be many possible - still undiscovered - combinations. Our method gives an algorithmic solution to the superactivation problem, and provides an efficient algorithmic solution for discovering “superactive” zero-capacity optical quantum channels. We analyze the superactivation property of the amplitude damping quantum channel model. This model has great importance in practical communications, since this channel model describes energy dissipation due to the noise of the optical channel. To discover these superactive zero-capacity channels, an extremely large set of possible quantum states has to be analyzed, however an efficient algorithmic framework is still missing for this purpose. We show a fundamentally new method of finding the conditions for “superactive” zero-capacity optical quantum channels.
The zero-error capacity of a channel is the rate at which it can send information perfectly, with zero probability of error, and has long been studied in classical information theory. We show that the zero-error capacity of quantum channels exhibits an extreme form of non-additivity, one which is not possible for classical channels, or even for the usual capacities of quantum channels. By combining probabilistic arguments with algebraic geometry, we prove that there exist channels E1 and E2 with no zero-error classical capacity whatsoever, C_0(E1) = C_0(E2) = 0, but whose joint zero-error quantum capacity is positive, Q_0(E1 x E2) >= 1. This striking effect is an extreme from of the superactivation phenomenon, as it implies that both the classical and quantum zero-error capacities of these channels can be superactivated simultaneously, whilst being a strictly stronger property of capacities. Superactivation of the quantum zero-error capacity was not previously known.
The superactivation of zero-capacity optical quantum channels makes it possible to use two zero-capacity optical quantum channels, with a positive joint capacity at the output. Here we show, that noisy Gaussian quantum channels with the help of entanglement and coherent optical devices, can be used to transmit quantum information perfectly. It will be demonstrated that using the superactivation effect, it is possible to develop efficient quantum repeaters with the elimination of the very inefficient and expensive purification process.