{"title":"Fock States in Additive Gaussian Noise Channels: Analytical and Numerical Considerations","authors":"Emad Zinoghli, Jawad A. Salehi","doi":"10.1049/qtc2.70011","DOIUrl":"10.1049/qtc2.70011","url":null,"abstract":"<p>In this paper, we study the effects of additive Gaussian noise on Fock states. We put forth a simple analytical formula for the resulting output states. Additionally, we conduct numerical analysis into several key properties of noisy Fock states, including their purity, nonclassicality and non-Gaussianness, with respect to the noise parameter. Finally, we examine the impact of noise on entangled N00N states, focusing on its entanglement-breaking effects, which we quantify using the logarithmic negativity measure. Regarding purity, we observe that for a fixed noise level, the purity of a noisy Fock state decreases as the number of photons increases. In terms of non-Gaussianity, we show that at any given noise level, higher Fock states exhibit higher non-Gaussianity compared to lower ones. Although all noisy Fock states eventually lose their nonclassical characteristics under sufficient noise, higher Fock states exhibit more pronounced nonclassical features in low-noise conditions, whereas lower Fock states show greater nonclassicality in high-noise environments. We quantitatively show that the <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>|</mo>\u0000 <mn>2002</mn>\u0000 <mo>〉</mo>\u0000 </mrow>\u0000 <annotation> $vert 2002rangle $</annotation>\u0000 </semantics></math> state is the most robust against additive Gaussian noise among the N00N states.</p>","PeriodicalId":100651,"journal":{"name":"IET Quantum Communication","volume":"6 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/qtc2.70011","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145037884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Raiyan Rahman, Md Shawmoon Azad, Mohammed Rakibul Hasan, Syed Emad Uddin Shubha, M. R. C. Mahdy
{"title":"Quantum Secure Image Transmission: A Chaos-Assisted Quantum Key Distribution Approach Using Entanglement","authors":"Raiyan Rahman, Md Shawmoon Azad, Mohammed Rakibul Hasan, Syed Emad Uddin Shubha, M. R. C. Mahdy","doi":"10.1049/qtc2.70016","DOIUrl":"10.1049/qtc2.70016","url":null,"abstract":"<p>The emergence of quantum computing has introduced unprecedented security challenges to conventional cryptographic systems, particularly in the domain of classical communications. Our research addresses these challenges by creatively combining quantum key distribution (QKD), specifically the E91 protocol, with logistic chaotic maps to establish a secure image transmission scheme. Our approach utilises the pseudo-randomness of chaotic systems alongside the security mechanisms inherent in quantum entanglement-based protocols. This framework leverages the E91 protocol for secure quantum key distribution to generate identical key pairs at both ends, followed by chaos encryption using the key as a basis for the parameters. This framework utilises the E91 protocol for secure quantum key distribution, leveraging maximally entangled pairs and CHSH inequality tests to detect eavesdropping and potential double-agent attacks by identifying nonentangled qubits, therefore maintaining key confidentiality. Furthermore, through quantitative simulations, we demonstrate the effectiveness of this scheme through key space and key sensitivity analysis, histogram analysis, information entropy analysis, execution time analysis, and differential attack analysis in end-to-end encryption. The results indicate a significant improvement in encryption and decryption efficiency, showcasing the scheme's potential as a viable solution against the vulnerabilities posed by quantum computing advancements. Our research offers a novel perspective on a critical aspect of cybersecurity applications across healthcare, defence, finance, and beyond in the realm of secure quantum communication.</p>","PeriodicalId":100651,"journal":{"name":"IET Quantum Communication","volume":"6 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/qtc2.70016","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145022224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Hybrid Quantum-Classical Convolutional Neural Network for Detection and Identification of Power Quality Disturbance","authors":"Yue Li, Xinhao Li, Haopeng Jia, Anjiang Liu, Qingle Wang, Shuqing Hao, Hao Liu","doi":"10.1049/qtc2.70013","DOIUrl":"10.1049/qtc2.70013","url":null,"abstract":"<p>Power quality disturbances (PQDs) pose significant challenges to modern power systems, necessitating precise detection and identification to mitigate their impacts and enhance grid robustness. In this paper, we propose a hybrid quantum-classical convolutional neural network model (PQDs-QC-CNN) for detecting and identifying power quality disturbances with high efficiency. The model employs a hierarchical framework consisting of quantum convolutional layers, fully connected layers and softmax regression, which can effectively extract multiscale features from disturbance data while mitigating overfitting. Utilising <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>N</mi>\u0000 </mrow>\u0000 <annotation> $N$</annotation>\u0000 </semantics></math> quantum bits, the model achieves a time complexity of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>O</mi>\u0000 <mrow>\u0000 <mo>(</mo>\u0000 <mrow>\u0000 <mtext>poly</mtext>\u0000 <mrow>\u0000 <mo>(</mo>\u0000 <mi>N</mi>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 </mrow>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation> $O(text{poly}(N))$</annotation>\u0000 </semantics></math> and a space complexity of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>O</mi>\u0000 <mrow>\u0000 <mo>(</mo>\u0000 <mi>N</mi>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation> $O(N)$</annotation>\u0000 </semantics></math>, ensuring scalability and efficiency. By conducting experiments on the datasets generated in compliance with IEEE Std 1159–2019, the results show a 100% detection accuracy and 99.56% identification accuracy, even with minimal quantum bits and simple configurations. Additionally, the model demonstrates robust noise resistance, maintaining approximately 98% identification accuracy across various noise scenarios. PQDs-QC-CNN not only shows promise for power system applications but also explores new avenues for quantum algorithm integration in smart grid technologies.</p>","PeriodicalId":100651,"journal":{"name":"IET Quantum Communication","volume":"6 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/qtc2.70013","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145012368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Prakash Dhakal, Babu R. Dawadi, Nanda Bikram Adhikari
{"title":"Performance Analysis of Different Quantum Key Distribution Protocols for Optimised Security and Efficiency","authors":"Prakash Dhakal, Babu R. Dawadi, Nanda Bikram Adhikari","doi":"10.1049/qtc2.70015","DOIUrl":"10.1049/qtc2.70015","url":null,"abstract":"<p>Quantum key distribution (QKD) protocols are techniques that use the laws of quantum physics to safely distribute cryptographic keys. QKD protocols are able to identify attempts at eavesdropping during the distribution of keys, possibly providing a better level of security than traditional encryption. We present a comparative evaluation of the three QKD protocols, namely, BB84, E91 and an enhanced BB84 (EBB84) with the goal of identifying the best balance between security and efficiency for practical quantum communication systems. Motivated by the growing need for quantum-resistant cryptography, extensive simulations in the Qiskit framework under both ideal and plausible noisy conditions is conducted, including depolarising, thermal relaxation, Pauli, amplitude damping and phase damping noise models. For each protocol, key lengths are varied from 200 to 3000 bits and, where relevant, simulated intercept–resend attacks to assess resilience against eavesdropping. The key performance metrics, QBER for BB84/EBB84 and the CHSH inequality parameter for E91 are computed over 50 iterations per scenario to ensure statistical robustness. The analysis reveals distinct trade-offs: EBB84 achieves superior early eavesdropper detection at short key lengths, whereas differences between BB84 and EBB84 diminishes as key lengths increases; E91 maintains strong entanglement-based security but is more sensitive to certain noise types. Regression analysis confirms that depolarising and amplitude damping noise most strongly influence QBER and CHSH degradation, whereas key length has a secondary effect. These findings mark the importance of adaptive key management and noise mitigation strategies and offer guidelines for integrating QKD into emerging network architectures such as SDN, 5G, and 6G.</p>","PeriodicalId":100651,"journal":{"name":"IET Quantum Communication","volume":"6 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/qtc2.70015","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144998636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"FedQCNN: A Privacy-Preserving Federated Quantum Convolutional Neural Network for Retinal Image Classification","authors":"Mahua Nandy Pal, Debashis De","doi":"10.1049/qtc2.70010","DOIUrl":"10.1049/qtc2.70010","url":null,"abstract":"<p>Quantum machine learning (QML) provides the opportunity for the success of an automated medical diagnostic system due to the effective representation of the solution space by quantum entangled states and faster optimisation through quantum superposition. Preserving medical data privacy is crucial while implementing an intelligent and efficient medical service provider system. The federated machine learning model is not only rich in diversified model experiences but also helps to protect patient data privacy. This paper proposes a secure, intelligent Internet of Healthcare Things (IoHT) application with a federated quantum convolutional neural network (FedQCNN) to classify medically significant retinal image patches. Following the gradient descent algorithm, we executed the model optimisation and performed the global aggregation using the weighted average of the local models' parameters. The proposed system achieves an evaluation accuracy of 96.8% on E-Ophtha retinal image dataset. We suggest over-the-air distributed machine learning with wireless multiple access channels to significantly save the scaled-up radio resource requirements for massive connectivity to ultra dense IoT devices. The research emphasises the significant progress of federated quantum machine learning and its prospects in the coming decades.</p>","PeriodicalId":100651,"journal":{"name":"IET Quantum Communication","volume":"6 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/qtc2.70010","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144929811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Dynamic Quantum Key Distribution for Microgrids With Distributed Error Correction","authors":"Suman Rath, Neel Kanth Kundu, Subham Sahoo","doi":"10.1049/qtc2.70014","DOIUrl":"10.1049/qtc2.70014","url":null,"abstract":"<p>Quantum key distribution (QKD) has often been hailed as a reliable technology for secure communication in cyber–physical microgrids. Even though unauthorised key measurements are not possible in QKD, attempts to read them can disturb quantum states leading to mutations in the transmitted value. Further, inaccurate quantum keys can lead to erroneous decryption producing <i>garbage</i> values, destabilising microgrid operation. QKD can also be vulnerable to node-level manipulations incorporating attack values into measurements before they are encrypted at the communication layer. To address these issues, this paper proposes a secure QKD protocol that can identify errors in keys and/or nodal measurements by observing violations in control dynamics. Additionally, the protocol uses a dynamic adjacency matrix-based formulation strategy enabling the affected nodes to reconstruct a trustworthy signal and replace it with the attacked signal in a multi-hop manner. This enables microgrids to perform nominal operations in the presence of adversaries who try to eavesdrop on the system causing an increase in the quantum bit error rate (QBER). We provide several case studies to showcase the robustness of the proposed strategy against eavesdroppers and node manipulations. The results demonstrate that it can resist unwanted observation and attack vectors that manipulate signals before encryption.</p>","PeriodicalId":100651,"journal":{"name":"IET Quantum Communication","volume":"6 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/qtc2.70014","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144930061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}