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

Optimal superdense coding through noisy channels by escorting qubits

Javid Ahmad Malik, Muzaffar Qadir Lone, Prince Ahmad Ganai

Published Feb 26, 2026• 0 citations
Publisher

Abstract

Abstract We introduce an escort-qubit–assisted protocol that restores and stabilizes superdense coding capacity in the presence of amplitude damping channel (ADC) noise. The protocol is analyzed under three fundamental noisy configurations: amplitude damping acting on Alice’s subsystem, on Bob’s subsystem, and on both subsystems covering all practically relevant scenarios. In the absence of protection, we show that ADC effects cause a monotonic degradation of the superdense coding capacity, driving it below the classical limit in the strong decoherence regime and completely erasing the quantum advantage. Our escort-qubit protocol overcomes this limitation by coherently tracking the channel-induced Kraus trajectories during entanglement distribution. Post-selection of the no-flip trajectory, projects the shared state onto a maximally entangled resource state, thereby recovering the optimal superdense coding capacity of two classical bits, independent of the noise strength and noisy configuration. Importantly, when all ADC trajectories are taken into account, the resulting average capacity although inherently suboptimal remains strictly above both the classical limit and the unprotected capacity across the entire decoherence range. These results establish the escort-qubit protocol as a powerful, scalable, and experimentally viable approach for preserving quantum advantage and enhancing information throughput in noisy quantum communication networks.

DOI
10.21203/rs.3.rs-8764753/v1

Related papers

Partial-measurement-enhanced high-dimensional superdense coding in amplitude damping channel with memory

Xing 兴 Xiao 肖, Zhipeng Yang, Yanling Li +2 more

Abstract We study the performance of high-dimensional superdense coding (HD-SDC) over an amplitude damping (AD) channel with memory and propose a protocol that leverages partial measurement and its reversal to enhance the channel capacity. By considering a two-qutrit system, we model the memory AD noise using a convex mixture of memoryless and perfectly memory AD channels. We demonstrate that the memory effect alone can mitigate the decay of the SDC capacity under noise. More significantly, we show that the application of partial measurement before the channel and its reversal after the channel can not only recover the capacity degraded by noise but, for certain non-maximally entangled initial states, even amplify it beyond the initial capacity. This amplification effect is governed by three key factors: the ground-state probability in the initial entangled state, the memory strength, and the partial measurement strength. Our results provide a practical strategy for enhancing quantum communication protocols in realistic noisy environments and highlight the synergistic benefits of memory noise and measurement-based control.

Chinese Physics B•Dec 4, 2025•0 citations

Enhancing the Fidelity of Dense Coding through Steane 7-Qubit Error Correction Under Noisy Channels

Shilpa Adla, Krishna Madhav Nukala, Sivvayalamarthi +3 more

Quantum communication protocols, such as superdense coding, offer significant advantages in information transfer by leveraging quantum entanglement. However, practical implementations are hindered by the presence of noise and decoherence in quantum systems. This study investigates the effectiveness of the Steane 7-qubit error correction code in mitigating the impact of noise on the superdense coding protocol. Simulations were performed using Qiskit Aer, incorporating depolarizing, amplitude damping, and phase damping noise models at varying strengths. The error rates were evaluated across multiple trials to assess the robustness of the encoded communication. The results demonstrate that the Steane code substantially improves the fidelity of information transmission, with varying levels of protection depending on the type of noise present. These findings contribute to a better understanding of error correction strategies for reliable quantum communication in noisy environments.

International Conference on Ubiquitous Computing and Intelligent Information Systems (ICUIS)•Nov 26, 2025•0 citations

Testbed Protocol for Adaptive Superdense Coding in Distributed Quantum Networks

Syed Emad Uddin Shubha, Tasnuva Farheen

Distributed quantum networks require robust protocols for high-capacity, noise-resilient communication between spatially separated nodes. Superdense coding, which leverages shared entanglement to transmit two classical bits per qubit, is a key primitive for benchmarking such networks. However, entanglement degradation from channel noise and decoherence poses major challenges for achieving scalable throughput in practical environments. We introduce a testbed protocol for adaptive superdense coding in distributed quantum networks (DQNs), integrating the five-qubit error correction code with a global, feedback-driven purification routine. By continuously monitoring quantum discord (QD) and entanglement of formation (EoF) via dedicated pilot pairs, our protocol dynamically tunes purification parameters to counteract amplitude and phase damping, while avoiding the loss of entangled pairs inherent to traditional schemes. Simulation results demonstrate that this hybrid quantum-classical approach enhances channel fidelity and throughput under realistic noise, providing a scalable testbed for distributed quantum error correction strategies and hybrid control in next-generation quantum networks.

IEEE International Conference on Quantum Computing and Engineering (QCE)•Aug 30, 2025•0 citations

Enhancing Dense Coding Reliability under Noisy Quantum Channels Through Redundancy Strategies

Krishna Madhav Nukala, Dadinaboina A. K.Rao, N. Nagasoudhamani +3 more

Quantum dense coding enables the transmission of two classical bits of information through the exchange of a single qubit, provided that an entangled state is shared between the communicating parties. While this protocol achieves a fundamental increase in channel capacity, its practical realization is strongly influenced by the presence of noise in realistic quantum channels. This work presents a simulation-based study of dense coding performance under two representative noise models: the depolarizing channel and the amplitude damping channel. Using Qiskit Aer, the bit error rate (BER), frame error rate (FER), and effective channel capacity are evaluated across a range of noise parameters. In addition, a classical threefold repetition strategy is examined as a lightweight error-mitigation technique. Results indicate that depolarizing noise produces more rapid degradation in both BER and channel capacity compared to amplitude damping, while repetition coding provides partial improvement in reliability at the expense of resource overhead. These findings highlight the trade-offs between efficiency and robustness in noisy implementations of dense coding and motivate further exploration of more advanced quantum error correction methods.

International Conference on Ubiquitous Computing and Intelligent Information Systems (ICUIS)•Nov 26, 2025•1 citation

Universal Entanglement Protection for Quantum Teleportation Over Amplitude Damping Channels With Various Entangled States

Sajede Harraz, Shuang Cong

Abstract Achieving high‐fidelity quantum teleportation requires the distribution of maximally entangled states through noiseless channels, a condition rarely met in practical implementations. In realistic environments, decoherence processes, such as amplitude damping, severely degrade entanglement quality. In this study, a universal strategy is proposed for protecting entanglement against amplitude damping noise by introducing escort qubits—ancillary qubits specifically designed to assist in the distribution process. This method involves CNOT operations and measurement of the escort qubits. Modeling the amplitude damping channel with a Lindblad master equation, it is showed analytically that the method achieves unit fidelity under ideal operations, independent of the damping rate, with a certain success probability. This method is applied to teleportation with Bell and W states, and compare its performance with weak measurement and environment‐assisted measurement protocols. This approach offers superior fidelity, experimental feasibility, and independence from noise parameters, as confirmed through simulation and Qiskit implementation.

Advanced Quantum Technologies•Sep 27, 2025•1 citation

Enhancing Quantum Dense Coding Robustness Using Information Entropy-Based Metrics

Syed Emad Uddin Shubha, Tasnuva Farheen

Superdense Coding is a cornerstone in secure quantum communication, exploiting pre-shared entanglement to encode two classical bits within a single qubit. However, noise and decoherence deteriorate entanglement quality, restricting both fidelity and channel capacity in practical settings. Traditional methods, such as error correcting codes or entanglement distillation, are generally inadequate for dynamically varying noise conditions. Moreover, reliance on fidelity alone may fail to capture more subtle noise effects. This work introduces an adaptive protocol that integrates the five-qubit perfect code with a novel global adaptive purification that avoids discarding entangled pairs. By monitoring two information entropy-based metrics, quantum discord (QD) and entanglement of formation (EoF) from pilot pairs, we dynamically tune a global unitary to counteract noise. Our simulations, under both amplitude and phase damping, indicate that this integrated strategy could significantly enhance superdense coding robustness while preserving high throughput, thereby offering a scalable pathway toward a high-capacity quantum internet.

arXiv:2504.12565•Apr 17, 2025•0 citations
Abstract We introduce an escort-qubit–assisted protocol that restores and stabilizes superdense coding capacity in the presence of amplitude damping channel (ADC) noise. The protocol is analyzed under three fundamental noisy configurations: amplitude damping acting on Alice’s subsystem, on Bob’s subsystem, and on both subsystems covering all practically relevant scenarios. In the absence of protection, we show that ADC effects cause a monotonic degradation of the superdense coding capacity, driving it below the classical limit in the strong decoherence regime and completely erasing the quantum advantage. Our escort-qubit protocol overcomes this limitation by coherently tracking the channel-induced Kraus trajectories during entanglement distribution. Post-selection of the no-flip trajectory, projects the shared state onto a maximally entangled resource state, thereby recovering the optimal superdense coding capacity of two classical bits, independent of the noise strength and noisy configuration. Importantly, when all ADC trajectories are taken into account, the resulting average capacity although inherently suboptimal remains strictly above both the classical limit and the unprotected capacity across the entire decoherence range. These results establish the escort-qubit protocol as a powerful, scalable, and experimentally viable approach for preserving quantum advantage and enhancing information throughput in noisy quantum communication networks.
Abstract We study the performance of high-dimensional superdense coding (HD-SDC) over an amplitude damping (AD) channel with memory and propose a protocol that leverages partial measurement and its reversal to enhance the channel capacity. By considering a two-qutrit system, we model the memory AD noise using a convex mixture of memoryless and perfectly memory AD channels. We demonstrate that the memory effect alone can mitigate the decay of the SDC capacity under noise. More significantly, we show that the application of partial measurement before the channel and its reversal after the channel can not only recover the capacity degraded by noise but, for certain non-maximally entangled initial states, even amplify it beyond the initial capacity. This amplification effect is governed by three key factors: the ground-state probability in the initial entangled state, the memory strength, and the partial measurement strength. Our results provide a practical strategy for enhancing quantum communication protocols in realistic noisy environments and highlight the synergistic benefits of memory noise and measurement-based control.
Quantum communication protocols, such as superdense coding, offer significant advantages in information transfer by leveraging quantum entanglement. However, practical implementations are hindered by the presence of noise and decoherence in quantum systems. This study investigates the effectiveness of the Steane 7-qubit error correction code in mitigating the impact of noise on the superdense coding protocol. Simulations were performed using Qiskit Aer, incorporating depolarizing, amplitude damping, and phase damping noise models at varying strengths. The error rates were evaluated across multiple trials to assess the robustness of the encoded communication. The results demonstrate that the Steane code substantially improves the fidelity of information transmission, with varying levels of protection depending on the type of noise present. These findings contribute to a better understanding of error correction strategies for reliable quantum communication in noisy environments.
Distributed quantum networks require robust protocols for high-capacity, noise-resilient communication between spatially separated nodes. Superdense coding, which leverages shared entanglement to transmit two classical bits per qubit, is a key primitive for benchmarking such networks. However, entanglement degradation from channel noise and decoherence poses major challenges for achieving scalable throughput in practical environments. We introduce a testbed protocol for adaptive superdense coding in distributed quantum networks (DQNs), integrating the five-qubit error correction code with a global, feedback-driven purification routine. By continuously monitoring quantum discord (QD) and entanglement of formation (EoF) via dedicated pilot pairs, our protocol dynamically tunes purification parameters to counteract amplitude and phase damping, while avoiding the loss of entangled pairs inherent to traditional schemes. Simulation results demonstrate that this hybrid quantum-classical approach enhances channel fidelity and throughput under realistic noise, providing a scalable testbed for distributed quantum error correction strategies and hybrid control in next-generation quantum networks.
Quantum dense coding enables the transmission of two classical bits of information through the exchange of a single qubit, provided that an entangled state is shared between the communicating parties. While this protocol achieves a fundamental increase in channel capacity, its practical realization is strongly influenced by the presence of noise in realistic quantum channels. This work presents a simulation-based study of dense coding performance under two representative noise models: the depolarizing channel and the amplitude damping channel. Using Qiskit Aer, the bit error rate (BER), frame error rate (FER), and effective channel capacity are evaluated across a range of noise parameters. In addition, a classical threefold repetition strategy is examined as a lightweight error-mitigation technique. Results indicate that depolarizing noise produces more rapid degradation in both BER and channel capacity compared to amplitude damping, while repetition coding provides partial improvement in reliability at the expense of resource overhead. These findings highlight the trade-offs between efficiency and robustness in noisy implementations of dense coding and motivate further exploration of more advanced quantum error correction methods.
Abstract Achieving high‐fidelity quantum teleportation requires the distribution of maximally entangled states through noiseless channels, a condition rarely met in practical implementations. In realistic environments, decoherence processes, such as amplitude damping, severely degrade entanglement quality. In this study, a universal strategy is proposed for protecting entanglement against amplitude damping noise by introducing escort qubits—ancillary qubits specifically designed to assist in the distribution process. This method involves CNOT operations and measurement of the escort qubits. Modeling the amplitude damping channel with a Lindblad master equation, it is showed analytically that the method achieves unit fidelity under ideal operations, independent of the damping rate, with a certain success probability. This method is applied to teleportation with Bell and W states, and compare its performance with weak measurement and environment‐assisted measurement protocols. This approach offers superior fidelity, experimental feasibility, and independence from noise parameters, as confirmed through simulation and Qiskit implementation.
Superdense Coding is a cornerstone in secure quantum communication, exploiting pre-shared entanglement to encode two classical bits within a single qubit. However, noise and decoherence deteriorate entanglement quality, restricting both fidelity and channel capacity in practical settings. Traditional methods, such as error correcting codes or entanglement distillation, are generally inadequate for dynamically varying noise conditions. Moreover, reliance on fidelity alone may fail to capture more subtle noise effects. This work introduces an adaptive protocol that integrates the five-qubit perfect code with a novel global adaptive purification that avoids discarding entangled pairs. By monitoring two information entropy-based metrics, quantum discord (QD) and entanglement of formation (EoF) from pilot pairs, we dynamically tune a global unitary to counteract noise. Our simulations, under both amplitude and phase damping, indicate that this integrated strategy could significantly enhance superdense coding robustness while preserving high throughput, thereby offering a scalable pathway toward a high-capacity quantum internet.