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.
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.
Quantum communication protocols such as superdense coding enable high-capacity information transfer using quantum entanglement. However, their performance is significantly affected by environmental noise and decoherence. This study presents an enhanced simulation framework for evaluating the Steane 7-qubit error correction code applied to superdense coding under realistic noise conditions. Building upon earlier models, the proposed work introduces robust circuit depth control mechanism and noise-aware simulation using Qiskit Aer to analyze depolarizing, amplitude damping, and phase damping errors. The system automatically encodes, decodes, and measures fidelity across varying noise probabilities, classifying results into performance tiers based on resilience. Comprehensive visualization through trend plots, heatmaps, and tier distributions offers clear insights into the impact of noise on quantum communication fidelity. The findings demonstrate that Steane encoding stabilizes fidelity within moderate noise levels, thereby improving the robustness of dense coding. This enhanced model provides a reproducible and scalable approach for studying quantum error correction, contributing to the design of noise-tolerant quantum communication 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.
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.
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.
The task of preserving entanglement against noises is of crucial importance for both quantum communication and quantum information transfer. To this aim, quantum error correction (QEC) codes may be employed to compensate, at least partially, the detriments induced by environmental noise that can be modeled as a bit-flip or a phase-flip error channel. In this paper, we investigate the effects of the simple three-qubit QEC codes to restore entanglement and nonlocality in a two-qubit system and consider two practical applications: superdense coding and quantum teleportation. Though the considered three-qubit QEC codes are known to perfectly work in the presence of very small noise, we show that they can avoid the sudden death of entanglement and improve the performance of the addressed protocols also for larger noise amplitudes.
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.