Physics

18 pages, 6270 KiB

Open AccessArticle

Enhancing Phase Change Material Efficiency in Wavy Trapezoidal Cavities: A Numerical Investigation of Nanoparticle Additives

by Ilias Benyahia, Aissa Abderrahmane, Yacine Khetib, Mashhour A. Alazwari, Obai Younis, Abdeldjalil Belazreg and Samir Laouedj

Physics 2025, 7(2), 17; https://doi.org/10.3390/physics7020017 - 27 May 2025

Abstract

Phase change materials (PCMs) are widely used in latent heat thermal energy storage systems (LHTESSs), but their low thermal conductivity limits performance. This study numerically investigates the enhancement of thermal efficiency in LHTESSs using nano-enhanced PCM (NePCM), composed of paraffin wax embedded with [...] Read more.

Phase change materials (PCMs) are widely used in latent heat thermal energy storage systems (LHTESSs), but their low thermal conductivity limits performance. This study numerically investigates the enhancement of thermal efficiency in LHTESSs using nano-enhanced PCM (NePCM), composed of paraffin wax embedded with copper (Cu) nanoparticles. The NePCM is confined within a trapezoidal cavity, with the base serving as the heat source. Four different cavity heights were analyzed: cases 1, 2, 3, and 4 with the heights D of 24 mm, 18 mm, 15 mm, and 13.5 mm, respectively. The finite element method was employed to solve the governing equations. The influence of two hot base temperatures (333.15 K and 338.15 K) and Cu nanoparticle volume fractions ranging from 0% to 6% was examined. The results show that incorporating Cu nanoparticles at 6 vol% (volume fraction) enhanced thermal conductivity and reduced melting time by 10.71%. Increasing the base temperature to 338.15 K accelerated melting by 65.55%. Among all configurations, case 4 exhibited the best performance, reducing melting duration by 15.12% compared to case 1. Full article

(This article belongs to the Section Applied Physics)

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7 pages, 833 KiB

Open AccessCommunication

Nonlinear Waves of a Surface Charge at the Boundary of a Semi-Infinite Cold Plasma in a Constant Magnetic Field

by Oleg M. Gradov

Physics 2025, 7(2), 16; https://doi.org/10.3390/physics7020016 - 14 May 2025

Viewed by 153

Abstract

In this paper, an equation describing nonlinear wave phenomena on the surface of magnetically active plasma in the approximation of the complete homogeneity of processes along the direction of the constant magnetic field is obtained. One of its solutions, in the form of [...] Read more.

In this paper, an equation describing nonlinear wave phenomena on the surface of magnetically active plasma in the approximation of the complete homogeneity of processes along the direction of the constant magnetic field is obtained. One of its solutions, in the form of a pulse having the shape of rapidly decaying oscillations with a changing period, is found to essentially depend on the magnitude of the magnetic field and shown to be approximately described by a specially selected analytical function. A detailed analytical analysis of the properties of another solitary wave formation existing under conditions of resonant coincidence of its carrier frequency with the corresponding value of its eigen surface oscillations in the considered cold semi-infinite plasma, in which a constant magnetic field is directed along its boundary, is also carried out. The conditions for the excitation of wave disturbances are determined, and analytical expressions that adequately describe the space–time structure of nonlinear waves are proposed. Full article

(This article belongs to the Section Statistical Physics and Nonlinear Phenomena)

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7 pages, 590 KiB

Open AccessCommunication

Shape Parameters for Decoupled Bands in ^99,101,103Ru, ^{101,103,105,107}Pd and ^{101,103,105,107}Cd Isotopes

by Annu Choudhary, Vinod Kumar and Amritanshu Shukla

Physics 2025, 7(2), 15; https://doi.org/10.3390/physics7020015 - 27 Apr 2025

Viewed by 224

Abstract

The shape parameters and energy spectra of the decoupled

h_{11 / 2}

bands in isotopes

{}^{99, 101, 103}{Ru}

, ^{101,103,105,107}Pd and ^{101,103,105,107}Cd are analyzed using the particle-plus-rotor model and cranked shell model calculations. The quasiparticle-plus-rotor (PRM) model [...] Read more.

The shape parameters and energy spectra of the decoupled

h_{11 / 2}

bands in isotopes

{}^{99, 101, 103}{Ru}

, ^{101,103,105,107}Pd and ^{101,103,105,107}Cd are analyzed using the particle-plus-rotor model and cranked shell model calculations. The quasiparticle-plus-rotor (PRM) model calculations are performed, considering both soft and rigid triaxial cores, using the constant-moment-of-inertia (CMI) and variable-moment-of-inertia (VMI) approaches. The asymmetry parameter

γ

obtained from the PRM model calculations is found to be consistent with the results obtained from the cranked shell model calculations when the core exhibited CMI behavior. Full article

(This article belongs to the Section Atomic Physics)

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12 pages, 4353 KiB

Open AccessArticle

Three-Photon Pulse Interference in a Tritter: A Novel Approach for a Three-Party Quantum Key Distribution Protocol

by Suryadi, Precious O. Amadi and Norshamsuri Ali

Physics 2025, 7(2), 14; https://doi.org/10.3390/physics7020014 - 22 Apr 2025

Viewed by 271

Abstract

This study presents a theoretical investigation into the interference properties of three photons in a six-port optical beam splitter, commonly referred to as a tritter. We examine various configurations of the relative phase differences among the input photons. Our findings reveal that fully [...] Read more.

This study presents a theoretical investigation into the interference properties of three photons in a six-port optical beam splitter, commonly referred to as a tritter. We examine various configurations of the relative phase differences among the input photons. Our findings reveal that fully constructive interference periodically occurs at a single output port for specific constant phase differences, while fully destructive interference simultaneously manifests at the remaining two output ports. These distinctive interference patterns arise across a wide range of specific phase difference combinations among the input photons. We suggest that these unique interference characteristics provide new insights into the potential implementation of a three-party quantum key distribution protocol. Such three-photon interference phenomena are crucial for facilitating symmetric secure key distribution among three parties. Full article

(This article belongs to the Section Applied Physics)

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19 pages, 519 KiB

Open AccessArticle

Applicability of Hydrodynamics in the Hadronic Phase of Heavy-Ion Collisions

by Ronald Scaria, Captain R. Singh and Raghunath Sahoo

Physics 2025, 7(2), 13; https://doi.org/10.3390/physics7020013 - 18 Apr 2025

Viewed by 358

Abstract

The hadronic phase and its dynamics in relativistic heavy-ion collisions are topics of immense discussion. The hadronic phase contains various massive hadrons with an abundance of the lightest hadron, i.e.,

π

-mesons (pions). In this paper, we consider that pions are in the [...] Read more.

The hadronic phase and its dynamics in relativistic heavy-ion collisions are topics of immense discussion. The hadronic phase contains various massive hadrons with an abundance of the lightest hadron, i.e.,

π

-mesons (pions). In this paper, we consider that pions are in the thermal equilibrium in the hadronic phase and use second-order viscous hydrodynamics for a medium of massive pions to obtain its expansion to the boundary of the kinetic freeze-out. We achieve the kinetic freeze-out boundary with the Knudsen number

Kn > 1

limit. When this condition is met, hydrodynamics expansion breaks down, and the mean free path becomes sufficiently large in comparison with the system size so that the particle yields are preserved. Further, we investigate the effect of the massive fluid on the resonance particle yields, including re-scattering and regeneration, along with the natural decay widths of the resonances. The resonances can play an essential role in determining the characteristics of the hadronic phase as they have sufficiently small lifetimes, which may be comparable to the hadronic phase lifetime. In the current study, we predict the hadronic phase lifetime, which is further used to determine the

K^{*} {(892)}^{0} / K

,

ϕ (1020) / K

, and

ρ {(770)}^{0} / π

yield ratios at the kinetic freeze-out. We calculate these ratios as a function of charged particle multiplicity and transverse momentum and compare the findings with experimental data. Our calculations qualitatively agree with the experimental data, indicating a possible hydrodynamical evolution of the hadronic phase. Full article

(This article belongs to the Section High Energy Physics)

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11 pages, 475 KiB

Open AccessArticle

Stability of Bi-Partite Correlations in Symmetric N-Qubit States Under Deterministic Measurements

by Carlos Muñoz, Luis Roa and Andrei B. Klimov

Physics 2025, 7(2), 12; https://doi.org/10.3390/physics7020012 - 9 Apr 2025

Viewed by 220

Abstract

In this paper, we analyze the distribution of bi-partite correlations in pure symmetric N-qubit states during local deterministic measurements, which ensure the same value of the reduced purities in the outcome states. It is analytically shown that all reduced purities grow in [...] Read more.

In this paper, we analyze the distribution of bi-partite correlations in pure symmetric N-qubit states during local deterministic measurements, which ensure the same value of the reduced purities in the outcome states. It is analytically shown that all reduced purities grow in the process of deterministic measurements. This allows us to characterize the stability of bi-partite entanglement during the optimal correlation transfer under single-qubit measurements in the asymptotic limit

N ≫ 1

. Full article

(This article belongs to the Special Issue A Themed Issue in Honor of Professor Viktor Dodonov—55 Years in Quantum Physics)

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5 pages, 186 KiB

Open AccessComment

On the Alleged Locality in the Schrödinger Picture. Comment on Vedral, V. Locality in the Schrödinger Picture of Quantum Mechanics. Physics 2024, 6, 793–800

by Charles Alexandre Bédard

Physics 2025, 7(2), 11; https://doi.org/10.3390/physics7020011 - 9 Apr 2025

Viewed by 225

Abstract

In his recent paper, Vlatko Vedral claims that the Schrödinger picture can describe quantum systems as locally as the Heisenberg picture, relying on a product notation for the density matrix. Here, I refute that claim. I show that the so-called ‘local factors’ in [...] Read more.

In his recent paper, Vlatko Vedral claims that the Schrödinger picture can describe quantum systems as locally as the Heisenberg picture, relying on a product notation for the density matrix. Here, I refute that claim. I show that the so-called ‘local factors’ in the product notation do not correspond to individual systems and therefore fail to satisfy Einsteinian locality. Furthermore, the product notation does not track where local gates are applied. Finally, I expose internal inconsistencies in the argument: if, as is also stated, the Schrödinger-picture locality ultimately depends on the explicit bookkeeping of all operations, then the explanatory power of the product notation is de facto undermined. Full article

(This article belongs to the Section Atomic Physics)

16 pages, 328 KiB

Open AccessReview

Dynamical Casimir Effect: 55 Years Later

by Viktor V. Dodonov

Physics 2025, 7(2), 10; https://doi.org/10.3390/physics7020010 - 29 Mar 2025

Viewed by 1474

Abstract

The paper represents a brief review of the publications in 2020 to 2024 related to the phenomena combined under the name of dynamical Casimir effect. Full article

(This article belongs to the Special Issue Matter-Radiation Interactions—In Memory of Professor Francesco Saverio Persico)

23 pages, 2658 KiB

Open AccessArticle

Self-Similar Bridge Between Regular and Critical Regions

by Vyacheslav I. Yukalov, Elizaveta P. Yukalova and Didier Sornette

Physics 2025, 7(2), 9; https://doi.org/10.3390/physics7020009 - 28 Mar 2025

Viewed by 308

Abstract

In statistical and nonlinear systems, two qualitatively distinct parameter regions are typically identified: the regular region, which is characterized by smooth behavior of key quantities; and the critical region, where these quantities exhibit singularities or strong fluctuations. Due to their starkly different properties, [...] Read more.

In statistical and nonlinear systems, two qualitatively distinct parameter regions are typically identified: the regular region, which is characterized by smooth behavior of key quantities; and the critical region, where these quantities exhibit singularities or strong fluctuations. Due to their starkly different properties, those regions are often perceived as being weakly related, if ever. However, here, we demonstrate that these regions are intimately connected, specifically showing how they have a relationship that can be explicitly revealed using self-similar approximation theory. The framework considered enables the prediction of observable quantities near the critical point based on information from the regular region, and vice versa. Remarkably, the method relies solely on asymptotic expansions with respect to a parameter, regardless of whether the expansion originates in the regular or critical region. The mathematical principles of self-similar theory remain consistent across both cases. We illustrate this consistency by extrapolating from the regular region to predict the existence, location, and critical indices of a critical point of an equation of state for a statistical system, even when no direct information about the critical region is available. Conversely, we explore extrapolation from the critical to the regular region in systems with discrete scale invariance, where log-periodic oscillations in observables introduce additional complexity. The findings provide insights and solutions applicable to diverse phenomena, including material fracture, stock market crashes, and earthquake forecasting. Full article

(This article belongs to the Special Issue Complexity in High Energy and Statistical Physics)

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