Quantum Computing: Latest Advances and Prospects

Topic Information

Dear Colleagues,

The field of quantum computing is rapidly transitioning from fundamental research to practical applications, standing at the forefront of technological innovation. This Topic seeks to collect the latest breakthroughs and forward-looking perspectives on quantum hardware, algorithms, and real-world applications. We welcome submissions covering advances in quantum processors (e.g., superconducting and trapped-ion), quantum error correction and fault-tolerant schemes, novel quantum algorithms (e.g., for simulation and optimization), and explorations of quantum advantage. Contributions that address the integration of classical systems and roadmap analyses for scalable quantum computing are also highly encouraged.

Prof. Dr. Mingxing Luo
Prof. Dr. Ming Li
Dr. Xue Yang
Topic Editors

Keywords

Participating Journals

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Applied Sciences applsci	2.9	6.1	2011	16 Days	CHF 2400	Submit
Electronics electronics	2.9	7.0	2012	16.4 Days	CHF 2400	Submit
Entropy entropy	2.1	4.9	1999	21.5 Days	CHF 2600	Submit
Mathematics mathematics	2.3	5.4	2013	17.3 Days	CHF 2600	Submit
Quantum Reports quantumrep	1.8	2.7	2019	19.8 Days	CHF 1400	Submit

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Published Papers (7 papers)

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17 pages, 1498 KB  

Open AccessArticle

Quantum-Layer-Based Authorized Hierarchical Multi-User Quantum Key Distribution Scheme Using GHZ States

by Jiaqi Han, Zhan Peng and Yinghua Jiang

Electronics 2026, 15(12), 2680; https://doi.org/10.3390/electronics15122680 - 17 Jun 2026

Viewed by 104

Abstract

As quantum communication evolves from point-to-point to multi-user networks, existing scalable schemes for multi-party quantum key distribution increasingly reveal their limitations in complex scenarios. These limitations are primarily manifested as a reliance on a central node, which results in insufficient hierarchical control capabilities [...] Read more.

As quantum communication evolves from point-to-point to multi-user networks, existing scalable schemes for multi-party quantum key distribution increasingly reveal their limitations in complex scenarios. These limitations are primarily manifested as a reliance on a central node, which results in insufficient hierarchical control capabilities of the system. Furthermore, existing schemes cannot enforce communication controllability at the quantum physical layer, making authorized communication difficult. To address these challenges, we propose a GHZ-state-based quantum-layer authorized hierarchical multi-user quantum key distribution scheme. By exploiting the global correlation of multipartite entanglement, authorization is mapped onto constraints imposed by managers’ measurement outcomes on receivers’ correlation structures, enabling hierarchically controlled key establishment. Specifically, any two users dynamically act as managers, whose measurements act as entanglement constraints dictating whether remaining users successfully establish a shared secret key. Theoretical analysis demonstrates the scheme guarantees correctness and consistency of key generation. Simulation results further indicate good robustness against typical types of channel noise, enabling stable controlled quantum key distribution within low-noise regimes. This work shifts communication authorization from classical mechanisms at the application layer to the quantum physical layer, providing a promising approach for secure quantum communication in complex networks. Full article

(This article belongs to the Topic Quantum Computing: Latest Advances and Prospects)

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44 pages, 897 KB  

Open AccessArticle

Tensor Network QAOA for Document Graphs: Narrative Map Extraction from News

by Brian Keith-Norambuena and Carolina Flores-Bustos

Electronics 2026, 15(11), 2487; https://doi.org/10.3390/electronics15112487 - 5 Jun 2026

Viewed by 154

Abstract

Selecting a compact subgraph of a document graph while maximising a learned coherence function, subject to flow conservation and temporal ordering, is important in storyline detection, event threading, and Narrative Map extraction. Existing Narrative Map methods either recover a single optimal path (a [...] Read more.

Selecting a compact subgraph of a document graph while maximising a learned coherence function, subject to flow conservation and temporal ordering, is important in storyline detection, event threading, and Narrative Map extraction. Existing Narrative Map methods either recover a single optimal path (a Narrative Trail) or solve a linear program with an output size which grows with graph density (Narrative Maps). We propose a hybrid classical–quantum pipeline that casts the problem as a Quadratic Unconstrained Binary Optimisation (QUBO) problem and solves it both with the Quantum Approximate Optimisation Algorithm (QAOA) and with off-the-shelf classical QUBO solvers (simulated annealing, Tabu search) on the same Hamiltonian; this approach uses a classical mean field active space reduction and Matrix Product State tensor network simulation to scale beyond 16 qubits. We evaluate node- and edge-level qubit encodings under a range of QAOA circuit variants (transverse field and XY mixers; classical warm-start deeper circuits) on a 418-document news corpus across four graph densities and ten endpoint pairs, and audit their reproducibility across optimiser seeds. The QUBO formulations—whether solved by QAOA or by classical QUBO solvers on the same Hamiltonian—produce maps averaging $4.7$–$9.0$ nodes versus $26.6$ for Narrative Maps ($p<{10}^{-7}$) and they are far more focused on their main storyline (main path fraction $0.61$–$0.99$ versus $0.20$). The Hamming-weight-preserving XY mixer goes the furthest: the node-level XY mixer variant produces the most compact ($4.7$ nodes) and most spine-focused ($0.99$ main path fraction) maps of any method tested, and a multi-seed audit identifies it as the most reproducible of the eight QAOA variants we compared. Main path coherence is on par with Narrative Maps’ and $0.031$–$0.072$ below the bottleneck-optimising baselines—Narrative Trails ($0.770$) and Iterative Maximin ($0.758$). These results position QAOA not as a uniformly stronger alternative but as a distinct trade-off region favouring compactness and spine focus over raw bottleneck coherence and corpus topic breadth. Full article

(This article belongs to the Topic Quantum Computing: Latest Advances and Prospects)

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32 pages, 9695 KB  

Open AccessArticle

Operational Causality Without Definite Order: Certifying Indefinite Causal Structure via a Causal Inequality and Causal Witness

by Horace T. Crogman

Quantum Rep. 2026, 8(2), 52; https://doi.org/10.3390/quantum8020052 - 3 Jun 2026

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Abstract

Quantum processes with indefinite causal order challenge the classical assumption that operations must occur in a single fixed temporal sequence. The quantum switch provides a concrete setting in which two operation orders, $A\prec B$ and $B\prec A$, are coherently controlled [...] Read more.

Quantum processes with indefinite causal order challenge the classical assumption that operations must occur in a single fixed temporal sequence. The quantum switch provides a concrete setting in which two operation orders, $A\prec B$ and $B\prec A$, are coherently controlled by a quantum system. In the strict process matrix formulation of the lazy guess your neighbour’s input (LGYNI) game, however, quantum theory, including the quantum switch, does not violate the standard causal inequality when probabilities are computed solely from local instruments. In this work, we study an extended control-assisted operational protocol in which the control system of the quantum switch is measured and used to define the task output. We compare increasingly expressive strategy classes, including single-qubit SU(2) operations, product target-ancilla operations, and entangling Cartan-decomposed two-qubit operations with generalized POVMs. Restricted models saturate or remain below the $3/4$ fixed-order benchmark, whereas the optimized Cartan + ancilla + POVM strategy reaches $P_{\mathrm{s}\mathrm{u}\mathrm{c}\mathrm{c}}^{\mathrm{e}\mathrm{x}\mathrm{t}}\approx 0.83596$, demonstrating enhanced task performance within the extended protocol. The optimized strategy remains operationally no-signaling to numerical precision and retains its extended protocol advantage under more than $25\%$ white noise admixture. These results identify the operational resources required for control-assisted quantum switch enhancement and support the view that indefinite temporal order can be used as a quantum informational resource without implying a breakdown of operational causality. Full article

(This article belongs to the Topic Quantum Computing: Latest Advances and Prospects)

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24 pages, 2936 KB  

Open AccessArticle

A Quantum-Accelerated Mapping Algorithm for Sequence Alignment

by Konstantinos Prousalis, Dimitris Ntalaperas, Konstantinos Georgiou, Andreas Kalogeropoulos, Thanos G. Stavropoulos, Theodora Karamanidou, Christos Papalitsas, Lefteris Angelis and Nikos Konofaos

Quantum Rep. 2026, 8(2), 51; https://doi.org/10.3390/quantum8020051 - 2 Jun 2026

Viewed by 313

Abstract

A novel quantum algorithm for biological sequence alignment is presented and analyzed. The large volumes of data generated through genome sequencing, de novo assembly, resequencing, and transcriptome sequencing at the DNA and RNA levels foreshadow the growing demand for higher computational power and [...] Read more.

A novel quantum algorithm for biological sequence alignment is presented and analyzed. The large volumes of data generated through genome sequencing, de novo assembly, resequencing, and transcriptome sequencing at the DNA and RNA levels foreshadow the growing demand for higher computational power and more sophisticated alignment methodologies. The rapid advancement of modern sequencing technologies in genomics has motivated the reconsideration of existing approaches for the design and implementation of alignment protocols. Emerging quantum computing accelerators may provide transformative solutions in this domain as quantum hardware progressively reaches higher levels of gate-operation maturity. This work proposes a computer-vision-based approach that exploits the unique properties of quantum entanglement within a dot-matrix representation to address the increasing demand for efficient processing of biological data. A quantum-accelerated protocol is developed and evaluated using the Qiskit software framework of IBM. Runtime experiments support the potential of the proposed methodology to provide advantageous sequence-alignment performance in terms of accuracy, completeness, and computational complexity. The system is evaluated under multiple operational conditions and demonstrates promising performance advantages. Full article

(This article belongs to the Topic Quantum Computing: Latest Advances and Prospects)

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15 pages, 2067 KB  

Open AccessArticle

Thermodynamic Consistency in Noise Modeling for Silicon Based Spin Qubits: A Comparative Study of Stochastic and Dissipative Dynamics

by Dimitrios Pourikas, Konstantinos Prousalis and Nikos Konofaos

Quantum Rep. 2026, 8(2), 50; https://doi.org/10.3390/quantum8020050 - 31 May 2026

Viewed by 921

Abstract

Silicon–germanium (Si/SiGe) quantum dots represent a preeminent architecture for scalable quantum computing; however, their performance remains fundamentally constrained by environmental decoherence. This work presents a comparative simulation study of a two-qubit system in Si/SiGe, evaluating the fidelity of various noise modeling frameworks under [...] Read more.

Silicon–germanium (Si/SiGe) quantum dots represent a preeminent architecture for scalable quantum computing; however, their performance remains fundamentally constrained by environmental decoherence. This work presents a comparative simulation study of a two-qubit system in Si/SiGe, evaluating the fidelity of various noise modeling frameworks under realistic conditions, including $1/f$ charge noise and phonon-mediated relaxation. We benchmark the Lindblad Master Equation against the Bloch–Redfield Master Equation, the Semiclassical Stochastic Hamiltonian method and the Monte Carlo Wavefunction (Quantum Jumps). Our analysis reveals that while semiclassical models effectively capture pure dephasing ($T_2^{*}$) dynamics, they fail to account for energy relaxation ($T_1$) at cryogenic temperatures, erroneously driving the system toward a high-entropy maximally mixed state. We propose the Quantum Trajectories method to resolve this discrepancy by incorporating discrete dissipation events, providing a thermodynamically consistent semi-classical framework. To demonstrate the scalability of our approach, we extend the simulation to a 4-qubit register, showing that the Quantum Trajectories method remains numerically robust and thermodynamically consistent as the Hilbert space dimension increases. Furthermore, we perform a magnetic field optimization analysis, identifying an operational “sweet spot” within the 0.1–0.5 T range that optimally balances the trade-offs between relaxation and dephasing. Full article

(This article belongs to the Topic Quantum Computing: Latest Advances and Prospects)

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11 pages, 571 KB  

Open AccessArticle

Verifying Quantum Network Nonlocality Based on the Extended Mermin Inequality

by Xinyue Li, Yan-Han Yang and Ming-Xing Luo

Quantum Rep. 2026, 8(2), 41; https://doi.org/10.3390/quantum8020041 - 1 May 2026

Viewed by 449

Abstract

This work proposes an extended Mermin inequality based on a hybrid classical model that involves only one classical source, with the remaining sources being post-quantum. In a chain-structured quantum network consisting of hybrid Einstein–Podolsky–Rosen (EPR) pairs and Greenberger–Horne–Zeilinger (GHZ) states, joint measurements are [...] Read more.

This work proposes an extended Mermin inequality based on a hybrid classical model that involves only one classical source, with the remaining sources being post-quantum. In a chain-structured quantum network consisting of hybrid Einstein–Podolsky–Rosen (EPR) pairs and Greenberger–Horne–Zeilinger (GHZ) states, joint measurements are performed at the central node, while local measurements are conducted at the peripheral nodes. This setup shows that the obtained quantum correlations can violate the proposed inequality with fewer measurement settings, thereby verifying network nonlocality. Furthermore, we extend this method to chain networks of arbitrary length n and show that the proposed inequality remains effective in verifying network nonlocality. Full article

(This article belongs to the Topic Quantum Computing: Latest Advances and Prospects)

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149 pages, 2314 KB  

Open AccessReview

A Technical Review of Quantum Computing Use Cases for Finance and Economics

by Manqoba Q. Hlatshwayo, Manav Babel, Dalila Islas-Sanchez and Konstantinos Georgopoulos

Quantum Rep. 2026, 8(1), 26; https://doi.org/10.3390/quantum8010026 - 17 Mar 2026

Viewed by 5465

Abstract

Quantum computing has been rapidly evolving as a field, with innovations driven by industry, academia, and government institutions. The technology has the potential to accelerate computation for solving complex problems across multiple industrial sectors. Finance and economics, with many problems exhibiting computationally heavy [...] Read more.

Quantum computing has been rapidly evolving as a field, with innovations driven by industry, academia, and government institutions. The technology has the potential to accelerate computation for solving complex problems across multiple industrial sectors. Finance and economics, with many problems exhibiting computationally heavy requirements, comprise a high-profile sector where quantum computing could have a significant impact. Therefore, it is important to identify and understand to what extent the technology could find utility in the sector. This technical review is written for quantum applications researchers, quantitative analysts in finance and economics, and researchers in related mathematical sciences. It is divided into two parts: (i) a survey of quantum algorithms pertinent to problems in finance and economics, and (ii) mapping of several use cases in the sector to the potential quantum algorithms presented in part (i). We discuss some challenges on the pathway to achieving quantum advantage. Ultimately, this review aims to be a catalyst for interdisciplinary research that will accelerate the advent of the practical advantages of quantum technologies to solve complex problems in this sector. Full article

(This article belongs to the Topic Quantum Computing: Latest Advances and Prospects)

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