James Hancock^*, Matthew Craven, Craig McNeile, Davide Vadacchino

Journal of Quantum Computing, Vol.7, pp. 55-79, 2025, DOI:10.32604/jqc.2025.068127 - 11 August 2025

Abstract This paper investigates Windfarm Layout Optimization (WFLO), where we formulate turbine placement considering wake effects as a Quadratic Unconstrained Binary Optimization (QUBO) problem. Wind energy plays a critical role in the transition toward sustainable power systems, but the optimal placement of turbines remains a challenging combinatorial problem due to complex wake interactions. With recent advances in quantum computing, there is growing interest in exploring whether hybrid quantum-classical methods can provide advantages for such computationally intensive tasks. We investigate solving the resulting QUBO problem using the Variational Quantum Eigensolver (VQE) implemented on Qiskit’s quantum computer simulator, More >

Duy Dao¹, Hervé Kerivin², Philippe Lacomme^2,*, Bogdan Vulpescu³

Journal of Quantum Computing, Vol.7, pp. 39-54, 2025, DOI:10.32604/jqc.2025.064764 - 30 May 2025

Abstract Track finding is a complex optimization problem, originally introduced in particle physics for the reconstruction of the trajectories of particles. A track is typically composed of several consecutive segments, which together form a smooth curve without any bifurcations. In this paper, we investigate various modeling approaches to assess their effectiveness and impact when applied to track finding, using both quantum and classical methods. We present implementations of three classical models using CPLEX, two quantum models on actual D-Wave quantum computers, and one quantum model on a D-Wave simulator. The results show that, while CPLEX provides… More >

Kaleb Dias Antoine KODO^1,*, Eugène C. EZIN^1,2

Journal of Quantum Computing, Vol.7, pp. 17-38, 2025, DOI:10.32604/jqc.2025.059089 - 08 April 2025

Abstract In the rapidly evolving domain of quantum computing, Shor’s algorithm has emerged as a groundbreaking innovation with far-reaching implications for the field of cryptographic security. However, the efficacy of Shor’s algorithm hinges on the critical step of determining the period, a process that poses a substantial computational challenge. This article explores innovative quantum optimization solutions that aim to enhance the efficiency of Shor’s period finding algorithm. The article focuses on quantum development environments, such as Qiskit and Cirq. A detailed analysis is conducted on three notable tools: Qiskit Transpiler, BQSKit, and Mitiq. The performance of More >

Oliver Crampton^1,*, Panagiotis Promponas^1,2, Richard Chen¹, Paul Polakos¹, Leandros Tassiulas², Louis Samuel¹

Journal of Quantum Computing, Vol.7, pp. 1-15, 2025, DOI:10.32604/jqc.2025.061275 - 21 March 2025

Abstract Distributed Quantum Computing (DQC) provides a means for scaling available quantum computation by interconnecting multiple quantum processor units (QPUs). A key challenge in this domain is efficiently allocating logical qubits from quantum circuits to the physical qubits within QPUs, a task known to be NP-hard. Traditional approaches, primarily focused on graph partitioning strategies, have sought to reduce the number of required Bell pairs for executing non-local CNOT operations, a form of gate teleportation. However, these methods have limitations in terms of efficiency and scalability. Addressing this, our work jointly considers gate and qubit teleportations introducing… More >

Priyanka¹, Damodarakurup Sajeev², Shaik Ahmed³, Shankar Pidishety³, Ram Soorat^3,*

Journal of Quantum Computing, Vol.6, pp. 53-66, 2024, DOI:10.32604/jqc.2024.054000 - 14 November 2024

Abstract The present study delves into the application of investigating quantum state behaviour, particularly focusing on coherent and superposition states. These states, characterized by their remarkable stability and precision, have found extensive utility in various domains of quantum mechanics and quantum information processing. Coherent states are valuable for manipulating quantum systems with accuracy. Superposition states allow quantum systems to exist in numerous configurations at the same time, which paves the way for quantum computing’s capacity for parallel processing. The research accentuates the crucial role of quantum error correction (QEC) in ensuring the stability and reliability of… More >

Eric Bourreau¹, Gérard Fleury², Philippe Lacomme^2,*

Journal of Quantum Computing, Vol.6, pp. 25-51, 2024, DOI:10.32604/jqc.2024.048792 - 25 October 2024

Abstract The paper presents a novel quantum method for addressing two fundamental routing problems: the Traveling Salesman Problem (TSP) and the Vehicle Routing Problem (VRP), both central to routing challenges. The proposed method, named the Indirect Quantum Approximate Optimization Algorithm (IQAOA), leverages an indirect solution representation using ranking. Our contribution focuses on two main areas: 1) the indirect representation of solutions, and 2) the integration of this representation into an extended version of QAOA, called IQAOA. This approach offers an alternative to QAOA and includes the following components: 1) a quantum parameterized circuit designed to simulate… More >

Mark Ariel Levin^*

Journal of Quantum Computing, Vol.6, pp. 15-24, 2024, DOI:10.32604/jqc.2024.047423 - 24 April 2024

Abstract Quantum algorithms for unstructured search problems rely on the preparation of a uniform superposition, traditionally achieved through Hadamard gates. However, this incidentally creates an auxiliary search space consisting of nonsensical answers that do not belong in the search space and reduce the efficiency of the algorithm due to the need to neglect, un-compute, or destructively interfere with them. Previous approaches to removing this auxiliary search space yielded large circuit depth and required the use of ancillary qubits. We have developed an optimized general solver for a circuit that prepares a uniform superposition of any N More >

Artyom M. Grigoryan^1,*, Sos S. Agaian²

Journal of Quantum Computing, Vol.6, pp. 1-14, 2024, DOI:10.32604/jqc.2023.026981 - 30 January 2024

Abstract In this work, we describe a method of calculation of the 1-D circular quantum convolution of signals represented by 3-qubit superpositions in the computational basis states. The examples of the ideal low pass and high pass filters are described and quantum schemes for the 3-qubit circular convolution are presented. In the proposed method, the 3-qubit Fourier transform is used and one addition qubit, to prepare the quantum superposition for the inverse quantum Fourier transform. It is considered that the discrete Fourier transform of one of the signals is known and calculated in advance and only More >

Indranil Bayal¹, Pradipta Panchadhyayee^1,2,*

Journal of Quantum Computing, Vol.5, pp. 71-79, 2023, DOI:10.32604/jqc.2023.045164 - 14 December 2023

Abstract The present model deals with a protocol which involves the generation and conversion of entanglement from path-spin (P-S) hybrid entanglement associated with half-spin particle to spin-spin (S-S) interparticle entanglement. This protocol finds its applications in quantum information processing via a series of operations which include a beam splitter, spin flipper, spin measurement, classical channel, unitary transformations. Finally, it leads to two particles having completely entangled spin variables, without any requirement of any simultaneous operation on the two particles. More >

Giuseppe Corrente^1,2,*, Carlo Vincenzo Stanzione^3,4, Vittoria Stanzione⁵

Journal of Quantum Computing, Vol.5, pp. 55-70, 2023, DOI:10.32604/jqc.2023.044786 - 14 December 2023

Abstract The Hamiltonian cycle problem (HCP), which is an NP-complete problem, consists of having a graph G with nodes and m edges and finding the path that connects each node exactly once. In this paper we compare some algorithms to solve a Hamiltonian cycle problem, using different models of computations and especially the probabilistic and quantum ones. Starting from the classical probabilistic approach of random walks, we take a step to the quantum direction by involving an ad hoc designed Quantum Turing Machine (QTM), which can be a useful conceptual project tool for quantum algorithms. Introducing several More >