Quantum Reports

22 pages, 351 KiB

Open AccessArticle

On the Holographic Spectral Effects of Time-Interval Subdivisions

by Sky Nelson-Isaacs

Quantum Rep. 2025, 7(1), 14; https://doi.org/10.3390/quantum7010014 - 19 Mar 2025

Viewed by 481

Drawing on formal parallels between scalar diffraction theory and quantum mechanics, it is demonstrated that quantum wavefunction propagation requires a holographic model of time. Measurable time manifests between interactions as a duration which is encoded in the frequency domain. It is thus a [...] Read more.

Drawing on formal parallels between scalar diffraction theory and quantum mechanics, it is demonstrated that quantum wavefunction propagation requires a holographic model of time. Measurable time manifests between interactions as a duration which is encoded in the frequency domain. It is thus a unified entity, and attempts to subdivide these intervals introduce oscillatory artifacts or spectral broadening, altering the system’s physical characteristics. Analogous to spatial holograms, where information is distributed across interference patterns, temporal intervals encode information as a discrete whole. This framework challenges the concept of continuous time evolution, suggesting instead that discrete trajectories define a frequency spectrum which holographically constructs the associated time interval, giving rise to the experimentally observed energy spread of particles in applications such as time-bin entanglement, ultra-fast light pulses, and the temporal double slit. A generalized model of quantum wavefunction propagation based on recursive Fourier transforms is discussed, and novel applications are proposed, including starlight analysis and quantum cryptography. Full article

(This article belongs to the Special Issue 100 Years of Quantum Mechanics)

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12 pages, 3259 KiB

Open AccessArticle

Thermodynamic and Magnetic Properties of Weakly Interacting Electron Gas Localized in a CdSe Cylindrical Core–Shell Quantum Dot

by Levon Tadevosyan, Hayk Ghaltaghchyan, Yevgeni Mamasakhlisov and Hayk Sarkisyan

Quantum Rep. 2025, 7(1), 13; https://doi.org/10.3390/quantum7010013 - 17 Mar 2025

Viewed by 375

Abstract

The thermodynamic and magnetic properties of weakly interacting electron gas localized in a CdSe cylindrical core–shell quantum dot in the presence of axial magnetic field are investigated. The entropy, mean energy, and heat capacity of such a gas are determined, and its magnetic [...] Read more.

The thermodynamic and magnetic properties of weakly interacting electron gas localized in a CdSe cylindrical core–shell quantum dot in the presence of axial magnetic field are investigated. The entropy, mean energy, and heat capacity of such a gas are determined, and its magnetic properties (magnetization and diamagnetic susceptibility) are studied. The possibilities of controlling thermodynamic parameters by changing the geometric parameters of quantum dots are shown. Calculations show that this gas has diamagnetic properties. These results provide insights into the features of physical processes occurring in thin core–shell quantum systems, which have potential applications in opto- and nanoelectronics. Full article

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9 pages, 3914 KiB

Open AccessArticle

Practical Implementation of Unconditionally Secure File Transfer Application with QKD and OTP

by Alin-Bogdan Popa, Bogdan-Calin Ciobanu and Pantelimon George Popescu

Quantum Rep. 2025, 7(1), 12; https://doi.org/10.3390/quantum7010012 - 14 Mar 2025

Viewed by 498

Abstract

With the looming threat of quantum computers capable of breaking classical encryption and the uncertainty regarding the security of post-quantum encryption algorithms, some highly sensitive applications aim for the highest level of security in information transfer: unconditional security. In this work we present [...] Read more.

With the looming threat of quantum computers capable of breaking classical encryption and the uncertainty regarding the security of post-quantum encryption algorithms, some highly sensitive applications aim for the highest level of security in information transfer: unconditional security. In this work we present an architecture and a practical implementation of a user-friendly unconditionally secure file transfer client based on quantum key distribution and one time pad cipher. We test the implementation on the live QKD research infrastructure within POLITEHNICA Bucharest, thus proving the approach is feasible for real information transfer use-cases. Full article

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5 pages, 259 KiB

Open AccessCommunication

Practitioners’ Rule of Thumb for Quantum Volume

by Emanuele G. Dalla Torre

Quantum Rep. 2025, 7(1), 11; https://doi.org/10.3390/quantum7010011 - 28 Feb 2025

Viewed by 484

Abstract

Quantum volume (QV) is a widely recognized metric for assessing the practical capabilities of quantum computers, as it provides an estimate of the largest quantum circuit that can be reliably executed. However, measuring QV on a real device requires comparing experimental outcomes with [...] Read more.

Quantum volume (QV) is a widely recognized metric for assessing the practical capabilities of quantum computers, as it provides an estimate of the largest quantum circuit that can be reliably executed. However, measuring QV on a real device requires comparing experimental outcomes with ideal theoretical results—a process that rapidly becomes computationally expensive. By examining the cumulative impact of errors in two-qubit gates, we present a simple, accessible `rule of thumb’ that relates the quantum volume directly to the average error rate of native gates. Our formula shows a strong agreement with experimental data from leading quantum computing platforms, including both superconducting and trapped-ion systems. This straightforward model offers a clear, intuitive guideline for predicting quantum hardware performance, enabling more informed decisions regarding circuit design and resource allocation. Full article

(This article belongs to the Special Issue Exclusive Feature Papers of Quantum Reports in 2024–2025)

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8 pages, 1195 KiB

Open AccessArticle

Cost-Efficient Pipelined Modular Polynomial Multiplier for Post-Quantum Cryptography Saber

by Hua Li

Quantum Rep. 2025, 7(1), 10; https://doi.org/10.3390/quantum7010010 - 20 Feb 2025

Viewed by 453

Abstract

The development of quantum computers presents a great challenge for current cryptographic algorithms. Post-quantum cryptography has been proposed to secure against quantum computers in the near future. Modular polynomial multiplication is a frequent arithmetic operation in post-quantum cryptography. In this paper, a low-cost [...] Read more.

The development of quantum computers presents a great challenge for current cryptographic algorithms. Post-quantum cryptography has been proposed to secure against quantum computers in the near future. Modular polynomial multiplication is a frequent arithmetic operation in post-quantum cryptography. In this paper, a low-cost and efficient pipelined architecture for modular polynomial multiplication in Saber has been proposed and synthesized with the Virtex UltraScale + xcu200-fsgd2104-2-e board. It can achieve a frequency of 250 MHz and only uses 11,499 LUTs, 7034 FFs and 32 IOs. Full article

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45 pages, 4266 KiB

Open AccessReview

Quantum Oncology

by Bruno F. E. Matarèse and Arnie Purushotham

Quantum Rep. 2025, 7(1), 9; https://doi.org/10.3390/quantum7010009 - 18 Feb 2025

Viewed by 2406

Abstract

Quantum core technologies (computing, sensing, imaging, communication) hold immense promise for revolutionizing cancer care. This paper explores their distinct capabilities in early-stage cancer diagnosis, improved clinical workflows, drug discovery, and personalized treatment. By overcoming challenges such as infrastructure and ethical considerations, these processes [...] Read more.

Quantum core technologies (computing, sensing, imaging, communication) hold immense promise for revolutionizing cancer care. This paper explores their distinct capabilities in early-stage cancer diagnosis, improved clinical workflows, drug discovery, and personalized treatment. By overcoming challenges such as infrastructure and ethical considerations, these processes can unlock faster diagnoses, optimize therapies, and enhance patient outcomes. Full article

(This article belongs to the Special Issue Exclusive Feature Papers of Quantum Reports in 2024–2025)

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21 pages, 295 KiB

Open AccessArticle

Unveiling the Fifth Dimension: A Novel Approach to Quantum Mechanics

by Frederick George Astbury

Quantum Rep. 2025, 7(1), 8; https://doi.org/10.3390/quantum7010008 - 15 Feb 2025

Viewed by 792

Abstract

Quantum mechanics (QM) has long challenged our understanding of time, space, and reality, with phenomena such as superposition, wave–particle duality, and quantum entanglement defying classical notions of causality and locality. Despite the predictive success of QM, its interpretations—such as the Copenhagen and many-worlds [...] Read more.

Quantum mechanics (QM) has long challenged our understanding of time, space, and reality, with phenomena such as superposition, wave–particle duality, and quantum entanglement defying classical notions of causality and locality. Despite the predictive success of QM, its interpretations—such as the Copenhagen and many-worlds interpretations—remain contentious and incomplete. This paper introduces Strip Theory, a novel framework that reconceptualises time as a two-dimensional manifold comprising foretime, the sequential dimension, and sidetime, an orthogonal possibility dimension representing parallel quantum outcomes. By incorporating sidetime, the theory provides a unified explanation for quantum superposition, coherence, and interference, resolving ambiguities associated with wavefunction collapse. The methods involve extending the mathematical formalism of QM into a five-dimensional framework, where sidetime is explicitly encoded alongside spatial and sequential temporal dimensions. The principal findings demonstrate that this model reproduces all measurable results of QM while addressing foundational issues, offering a clearer and more deterministic interpretation of quantum phenomena. Furthermore, the framework provides insights into quantum coherence, wave–particle duality, and the philosophical implications of free will. These results suggest that Strip Theory can serve as a bridge between interpretations and provide a deeper understanding of time and reality, advancing both theoretical and conceptual horizons. Full article

(This article belongs to the Special Issue 100 Years of Quantum Mechanics)

11 pages, 297 KiB

Open AccessArticle

Transition from Inflation to Dark Energy in Superfluid Vacuum Theory

by Konstantin G. Zloshchastiev

Quantum Rep. 2025, 7(1), 7; https://doi.org/10.3390/quantum7010007 - 8 Feb 2025

Viewed by 842

Abstract

The laminar constant-velocity superflow of a physical vacuum modelled by logarithmic quantum Bose liquid is considered. We demonstrate that this three-dimensional non-relativistic quantum flow generates a four-dimensional relativistic quinton system, which comprises the dilaton and quintom (a combination of the quintessence and tachyonic [...] Read more.

The laminar constant-velocity superflow of a physical vacuum modelled by logarithmic quantum Bose liquid is considered. We demonstrate that this three-dimensional non-relativistic quantum flow generates a four-dimensional relativistic quinton system, which comprises the dilaton and quintom (a combination of the quintessence and tachyonic phantom fields); all three fields are thus shown to be projections of the dynamical evolution of superfluid vacuum density and its fluctuations onto the measuring apparatus of a relativistic observer. The unified model describes the transition from the inflationary period in the early universe to the contemporary accelerating expansion of the universe, commonly referred to as the “dark energy” period. The quintessence and tachyonic scalar components of the derived model turn out to be non-minimally coupled, which is a hitherto unexplored generalization of cosmological phantom models. Full article

(This article belongs to the Special Issue Exclusive Feature Papers of Quantum Reports in 2024–2025)

20 pages, 650 KiB

Open AccessArticle

Decoherence, Locality, and Why dBB Is Actually MWI

by Per Arve

Quantum Rep. 2025, 7(1), 6; https://doi.org/10.3390/quantum7010006 - 31 Jan 2025

Viewed by 1190

Abstract

In the de Broglie Bohm pilot-wave theory and the many-worlds interpretation, unitary development of the quantum state is universally valid. They differ in that de Broglie and Bohm assumed that there are point particles with positions that evolve in time and that our [...] Read more.

In the de Broglie Bohm pilot-wave theory and the many-worlds interpretation, unitary development of the quantum state is universally valid. They differ in that de Broglie and Bohm assumed that there are point particles with positions that evolve in time and that our observations are observations of the particles. The many-worlds interpretation is based on the fact that the quantum state can explain our observations. Both interpretations rely on the decoherence mechanism to explain the disappearance of interference effects at a measurement. From this fact, it is argued that for the pilot-wave theory to work, circumstances must be such that the many-worlds interpretation is a viable alternative. However, if this is the case, the de Broglie–Bohm particles become irrelevant to any observer. They are truly hidden. The violation of locality and the corresponding violation of Lorenz invariance are good reasons to believe that dBB particles do not exist. Full article

(This article belongs to the Special Issue Exclusive Feature Papers of Quantum Reports in 2024–2025)

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13 pages, 1681 KiB

Open AccessArticle

An Introduction to Quantum Mechanics Through Neuroscience and CERN Data

by Héctor Reyes-Martín and María Arroyo-Hernández

Quantum Rep. 2025, 7(1), 5; https://doi.org/10.3390/quantum7010005 - 21 Jan 2025

Viewed by 1276

Abstract

(1) Background: One of the greatest challenges students face when studying quantum mechanics is the lack of daily experience and intuition about its concepts. This article introduces a holistic activity designed to present some foundational ideas of quantum mechanics in a new pedagogical [...] Read more.

(1) Background: One of the greatest challenges students face when studying quantum mechanics is the lack of daily experience and intuition about its concepts. This article introduces a holistic activity designed to present some foundational ideas of quantum mechanics in a new pedagogical approach to enhance students’ motivation. Using real open data from CERN, the activity connects classical concepts of dynamics and electromagnetism to their quantum counterparts, emphasizing both their similarities and differences. Teaching physics must consider the way the brain learns. That is why the activity is based on observed neuroscientific principles of physics learning. The approach maintains the rigor and precision required for these abstract concepts. (2) Methods: To evaluate the activity’s impact by gender, intrinsic motivation was assessed using a Likert-type scale with 81 undergraduate students from fields including artificial intelligence systems engineering, computer engineering, mathematical engineering, and architecture. (3) Results: a Mann–Whitney U test analysis indicates the activity significantly enhances students’ intrinsic motivation to study quantum mechanics, with improvements observed in both male and female students. (4) Conclusions: This result highlights the potential of the activity to promote greater interest in physics, both in men and women, since no significant differences have been observed between both samples. Full article

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21 pages, 501 KiB

Open AccessArticle

Towards Ginzburg–Landau Bogomolny Approach and a Perturbative Description of Superconducting Structures

by Łukasz T. Stȩpień and Krzysztof Pomorski

Quantum Rep. 2025, 7(1), 4; https://doi.org/10.3390/quantum7010004 - 19 Jan 2025

Viewed by 970

Abstract

The Bogomolny approach to the Ginzburg–Landau equations in the context of strong and semi-strong necessary conditions is formulated for various superconducting structures in a quasi-one-dimensional description, considering both flat and curved geometries. This formulation is justified by a perturbative approach to the Ginzburg–Landau [...] Read more.

The Bogomolny approach to the Ginzburg–Landau equations in the context of strong and semi-strong necessary conditions is formulated for various superconducting structures in a quasi-one-dimensional description, considering both flat and curved geometries. This formulation is justified by a perturbative approach to the Ginzburg–Landau theory applied to a superconducting structure that is polarized by an electric charge moving across two neighboring quantum dots. The situation considered involves an interface between a Josephson junction and a semiconductor quantum dot system in a one-dimensional setting. Full article

(This article belongs to the Special Issue Semiconductor and Superconductor Quantum Devices)

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19 pages, 610 KiB

Open AccessFeature PaperReview

Improving the Solving of Optimization Problems: A Comprehensive Review of Quantum Approaches

by Deborah Volpe, Giacomo Orlandi and Giovanna Turvani

Quantum Rep. 2025, 7(1), 3; https://doi.org/10.3390/quantum7010003 - 7 Jan 2025

Viewed by 2006

Abstract

Optimization is a crucial challenge across various domains, including finance, resource allocation, and mobility. Quantum computing has the potential to redefine the way we handle complex problems by reducing computational complexity and enhancing solution quality. Optimization, particularly of objective functions, stands to benefit [...] Read more.

Optimization is a crucial challenge across various domains, including finance, resource allocation, and mobility. Quantum computing has the potential to redefine the way we handle complex problems by reducing computational complexity and enhancing solution quality. Optimization, particularly of objective functions, stands to benefit significantly from quantum solvers, which leverage principles of quantum mechanics like superposition, entanglement, and tunneling. The Ising and Quadratic Unconstrained Binary Optimization (QUBO) models are the most suitable formulations for these solvers, involving binary variables and constraints treated as penalties within the overall objective function. To harness quantum approaches for optimization, two primary strategies are employed: exploiting quantum annealers—special-purpose optimization devices—and designing algorithms based on quantum circuits. This review provides a comprehensive overview of quantum optimization methods, examining their advantages, challenges, and limitations. It demonstrates their application to real-world scenarios and outlines the steps to convert generic optimization problems into quantum-compliant models. Lastly, it discusses available tools and frameworks that facilitate the exploration of quantum solutions for optimization tasks. Full article

(This article belongs to the Special Issue Exclusive Feature Papers of Quantum Reports in 2024–2025)

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31 pages, 10192 KiB

Open AccessReview

A Comprehensive Review of Quantum Circuit Optimization: Current Trends and Future Directions

by Krishnageetha Karuppasamy, Varun Puram, Stevens Johnson and Johnson P. Thomas

Quantum Rep. 2025, 7(1), 2; https://doi.org/10.3390/quantum7010002 - 1 Jan 2025

Viewed by 3378

Abstract

Optimizing quantum circuits is critical for enhancing computational speed and mitigating errors caused by quantum noise. Effective optimization must be achieved without compromising the correctness of the computations. This survey explores recent advancements in quantum circuit optimization, encompassing both hardware-independent and hardware-dependent techniques. [...] Read more.

Optimizing quantum circuits is critical for enhancing computational speed and mitigating errors caused by quantum noise. Effective optimization must be achieved without compromising the correctness of the computations. This survey explores recent advancements in quantum circuit optimization, encompassing both hardware-independent and hardware-dependent techniques. It reviews state-of-the-art approaches, including analytical algorithms, heuristic strategies, machine learning-based methods, and hybrid quantum-classical frameworks. The paper highlights the strengths and limitations of each method, along with the challenges they pose. Furthermore, it identifies potential research opportunities in this evolving field, offering insights into the future directions of quantum circuit optimization. Full article

(This article belongs to the Special Issue Quantum Computing: A Taxonomy, Systematic Review, and Future Directions)

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19 pages, 3849 KiB

Open AccessArticle

Quantum Computation of the Cobb–Douglas Utility Function via the 2D Clairaut Differential Equation

by Isabel Cristina Betancur-Hinestroza, Éver Alberto Velásquez-Sierra, Francisco J. Caro-Lopera and Álvaro Hernán Bedoya-Calle

Quantum Rep. 2025, 7(1), 1; https://doi.org/10.3390/quantum7010001 - 29 Dec 2024

Viewed by 942

Abstract

This paper introduces the integration of the Cobb–Douglas (CD) utility model with quantum computation using the Clairaut-type differential formula. We propose a novel economic–physical model employing envelope theory to establish a link with quantum entanglement, defining emergent probabilities in the optimal utility function [...] Read more.

This paper introduces the integration of the Cobb–Douglas (CD) utility model with quantum computation using the Clairaut-type differential formula. We propose a novel economic–physical model employing envelope theory to establish a link with quantum entanglement, defining emergent probabilities in the optimal utility function for two goods within a given expenditure limit. The study explores the interaction between the CD model and quantum computation, emphasizing system entropy and Clairaut differential equations in understanding utility’s optimal envelopes. Algorithms using the 2D Clairaut equation are introduced for the quantum formulation of the CD function, showcasing representation in quantum circuits for one and two qubits. Our findings, validated through IBM-Q simulations, align with the predictions, demonstrating the robustness of our approach. This methodology articulates the utility–budget relationship through envelope representation, where normalized intercepts signify probabilities. The precision of our results, especially in modeling quantum entanglement, surpasses that of IBM-Q simulations, which require extensive iterations for similar accuracy. Full article

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Quantum Rep., Volume 7, Issue 1 (March 2025) – 14 articles

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