Brazilian Journal of Physics最新文献

{"title":"Unconventional Phonon Blockade in a Nanomechanical Resonator Coupled to Double Qubit System","authors":"Debabrata Ganthya,&nbsp;Arumay Parai,&nbsp;Paresh Chandra Jana","doi":"10.1007/s13538-025-01795-w","DOIUrl":"10.1007/s13538-025-01795-w","url":null,"abstract":"<div><p>Our theoretical and numerical study explores the phonon statistics of a nanomechanical resonator-qubit system which consists of one nanomechanical and two qubit modes in which the mechanical genre is coupled with both the qubit modes and the mechanical mode exhibits Kerr nonlinearity. We analytically apprehend the optimal conditions of anomalistic phonon blockade created by destructive interference between different transition pathways. Our numerically assessment values the second-order phonon correlation function and studies its dependence on different system parameters. It is observed that the analytically obtained optimal conditions are supported by the numerical results.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 4","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143949657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Differential Geometry of Contextuality","authors":"Sidiney B. Montanhano","doi":"10.1007/s13538-025-01779-w","DOIUrl":"10.1007/s13538-025-01779-w","url":null,"abstract":"<div><p>Contextuality has long been associated with topological properties. In this work, such a relationship is elevated to identification in the broader framework of generalized contextuality. We employ the usual identification of states, effects, and transformations as vectors in a vector space and encode them into a tangent space, rendering the noncontextual conditions the generic condition that discrete closed paths imply null phases in valuations, which are immediately extended to the continuous case. Contextual behavior admits two equivalent interpretations in this formalism. In the geometric or intrinsic-realistic view, termed “Schrödinger,” flat space is imposed, leading to contextual behavior being expressed as non-trivial holonomy of probabilistic functions, analogous to the electromagnetic tensor. As a modification of the valuation function, we use the curvature to connect contextuality with interference, noncommutativity, and signed measures. In the topological or participatory-realistic view, termed “Heisenberg,” valuation functions must satisfy classical measure axioms, resulting in contextual behavior needing to be expressed as topological defects in the structure of events, leading to non-trivial monodromy. We utilize such defects to connect contextuality with non-embeddability and to construct a generalized Vorob’ev theorem, which formalizes the inevitability of noncontextuality. We identify in this formalism the contextual fraction for models with outcome-determinism and propose a pathway to address disturbance in ontological models as non-trivial transition maps. Finally, we discuss how these two views for encoding contextuality relate to interpretations of quantum theory.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 4","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143944239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Adiabatic Bulk Modulus and Sound Velocity of Nematic Liquid Crystals in the Isotropic Phase","authors":"Carlindo Vitoriano","doi":"10.1007/s13538-025-01794-x","DOIUrl":"10.1007/s13538-025-01794-x","url":null,"abstract":"<div><p>We obtain an expression for the sound velocity <span>(varvec{v}_{varvec{s}})</span> in the isotropic phase of nematic liquid crystals from the nematodynamics that incorporates the energetic coupling between <span>(varvec{Q}_{varvec{alpha beta }}varvec{(} textbf{r}varvec{)})</span> (the order parameter of the nematic-isotropic transition) and inhomogeneities in the local mass density <span>(varvec{rho }varvec{(} textbf{r}varvec{)})</span>. It differs from the well-known formula <span>(varvec{v}_{varvec{s}}varvec{=}sqrt{varvec{B}_{varvec{s}}varvec{/}varvec{rho }_{varvec{0}}})</span>, in which <span>(varvec{B}_{varvec{s}})</span> is the adiabatic bulk modulus and <span>(varvec{rho }_{varvec{0}})</span> is the average value of <span>(varvec{rho }varvec{(} textbf{r}varvec{)})</span>. Using the measured values of <span>(varvec{v}_{varvec{s}})</span> in the regime of low frequencies, we then calculate <span>(varvec{B}_{varvec{s}})</span> as a function of temperature for three different liquid crystals. The critical form of <span>(varvec{B}_{varvec{s}})</span> that emerges is unexpected, and its physical interpretation is discussed in terms of the Anderson-Grüneisen parameter. An explanation for the critical dip of <span>(varvec{v}_{varvec{s}})</span> near the nematic-isotropic transition is provided.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 4","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143944237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photoluminescence Property and Concentration Quenching of Orange-Red–Emitting Samarium Activated BaAl2O4 Phosphor for White LEDs","authors":"Rupesh S. Wandhare,&nbsp;Roshana T. Maske,&nbsp;A. N. Yerpude,&nbsp;N. R. Pawar,&nbsp;Shrikant M. Suryawanshi,&nbsp;S. J. Dhoble","doi":"10.1007/s13538-025-01791-0","DOIUrl":"10.1007/s13538-025-01791-0","url":null,"abstract":"<div><p>A series of Sm³⁺ activated BaAl₂O₄ phosphors was effectively synthesized by a known combustion method. Structural and optical properties are investigated by using X-ray diffraction pattern (XRD), Fourier transform infrared (FTIR), and photoluminescence (PL) analysis. The XRD of the prepared sample exhibits that all the samples prepared are in a single phase and match with standard JCPDS no. 01–072-1331. The XRD pattern indicates a hexagonal structure. The FTIR spectra of the BaAl₂O₄ sample show the stretching vibrations of aluminum-oxygen, barium-oxygen, and barium-oxygen-aluminum bonds, confirming the presence of the BaAl₂O₄ structure. The luminescence properties are broadly investigated by recording their PL excitation and emission spectra. The BaAl₂O₄:Sm³⁺ phosphors show a strong absorption range in 340–420 nm, which is well suited for application in LEDs. Under the excitation wavelength of 403 nm, the BaAl₂O₄:Sm³⁺ phosphor emits yellow, orange, and red emissions along the Commission Internationale de l'Éclairage (CIE) chromaticity coordinates found at 565 nm (0.408, 0.589), 603 nm (0.640, 0.359), and 650 nm (0.725, 0.274) (0.615). The optimal doping concentration of Sm³⁺ doped BaAl₂O₄ is at 1 mol %. The concentration mechanism is studied, and this mechanism arises from the dipole–dipole interaction between Sm³⁺ ions. The results demonstrate that BaAl₂O₄:Sm³⁺ phosphors have the potential to function as red–orange phosphors for white LEDs.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 4","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143944238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Camera-Based Measurement of Glucose Concentration in Aqueous Solution: Achieving High Precision and Accuracy with Frame Accumulation and Pixel Stacking","authors":"Gang Li,&nbsp;Sonia Mustafa,&nbsp;Adnan Munawar,&nbsp;Ling Lin","doi":"10.1007/s13538-025-01789-8","DOIUrl":"10.1007/s13538-025-01789-8","url":null,"abstract":"<div><p>Accurate measurement of glucose concentration in solution is imperative for diverse scientific applications. In this study, conducted at Tianjin University in 2024, the optical measurement accuracy of glucose in aqueous solution was substantially improved using a novel approach of pixel stacking and frame accumulation. Glucose solutions (<i>n</i> = 28) of different concentrations (range, 0.0–5.0%) were prepared, and the transmitted light intensity from these solutions was recorded using a polarization-sensitive camera. To improve the signal-to-noise ratio (SNR), we used frame accumulation and signal superposition of multiple pixels. The results showed a linear decrease in optical intensity captured by the camera with increasing glucose concentration in the solution. Following frame accumulation and pixel stacking, a substantial enhancement in precision and accuracy up to a factor of 1000 was achieved. Moreover, three algorithms including partial least squares (PLS) model, support vector machine (SVM) model, and random forest (RF) model were constructed and trained on one set of the samples and then used to blindly predict another set of the samples. The prediction of glucose concentration by the PLS model showed a minimum root mean square error (RMSE) of 0.2653, mean square error (MSE) of 0.0704, and a correlation coefficient of 0.9879 between the measured optical intensity and the glucose concentration. The use of frame accumulation and pixel stacking methods substantially improved glucose measurement accuracy.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 4","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143932307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of the Dependence of the Superconducting Critical Temperature of HG-1201 on the Crystal Lattice c/a Ratio Under Ambient and High-Pressure Conditions","authors":"Abdullo Ahadov,&nbsp;Davron Dzhuraev","doi":"10.1007/s13538-025-01792-z","DOIUrl":"10.1007/s13538-025-01792-z","url":null,"abstract":"<div><p>Increasing the critical temperature of superconducting materials, particularly the goal of achieving room temperature, remains one of the significant challenges in the field. Addressing this challenge requires a comprehensive understanding of the factors influencing critical temperature. Specifically, it is hypothesized that increasing the interlayer distance between <i>Cu</i> <span>({O}_{2})</span> planes, along with a corresponding reduction in the surface area of these planes or an increase in the <i>c/a</i> ratio of the crystal lattice constants, could elevate the critical temperature of high-temperature cuprate superconductors. In this study, we investigate the relationship between critical temperature and the <i>c/a</i> ratio at various doping levels of the single <i>Cu</i> <span>({O}_{2})</span> layer cuprate superconductor <span>(Hg{Ba}_{2}Cu{O}_{4+delta })</span> (Hg-1201), which exhibits the highest known critical temperature, under both atmospheric and high-pressure conditions. Our results indicate no significant correlation between critical temperature and the <i>c/a</i> ratio under atmospheric pressure. However, under applied external pressure, we show a generally decreasing critical temperature as a function of the <i>c/a</i> ratio. These findings suggest that parameters related to the <i>Cu</i> <span>({O}_{2})</span> planes in Hg-1201 and other high-temperature cuprate superconductors are insufficient to explain the variations in critical temperature. Furthermore, we conclude that charge reservoirs, carrier dynamics, and inter-electronic orbital interactions significantly influence the fluctuations in critical temperature.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 4","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143932253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Viscosity on Highly Relativistic Ion Acoustic Shock Waves in an Electron–Positron-Ion Plasma with the Pressure Variation Equation","authors":"R. Das,&nbsp;M. Das,&nbsp;E. Hincal,&nbsp;K. Hosseini,&nbsp;F. Alizadeh","doi":"10.1007/s13538-025-01783-0","DOIUrl":"10.1007/s13538-025-01783-0","url":null,"abstract":"<div><p>The Korteweg-de Vries–Burgers (KdV–B) equation is developed using the reductive perturbation method (RPM) to investigate the propagation properties of ion acoustic shock waves (IASHWs) in a highly relativistic plasma containing relativistic thermal ions, thermal positrons, and non-thermal electrons. Only fast mode is found to exist in the electron–positron-ion (epi) plasma of IASHWs. The impact of varying plasma parameters on the shock wave amplitude is examined. The behaviour of nonlinear and dispersion coefficients under the influence of relativistic factor <span>((nu ))</span> and ion to electron temperature ratio <span>((alpha ))</span> has been examined. Shock waves are produced by increasing the values of the relativistic factor, positron concentration <span>((delta ))</span>, and electron to positron temperature ratio <span>((sigma ))</span>. It is also found that the presence of the kinematic viscosity <span>(({eta }_{i0}))</span> generates shock wave structures. Moreover, the shock wave amplitude reduces with a higher order relativistic impact and increases with a lower order relativistic effect. As a result, shock waves appear to have a significantly bigger amplitude in a non-relativistic environment. The findings might be applicable to both inertial confinement fusion plasmas and astrophysical plasmas.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 4","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13538-025-01783-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143929920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unraveling the Decay Dynamics of Heavy-Ion Induced Reactions Forming Lanthanide Nuclei at Low-Energy Regime","authors":"Manpreet Kaur,&nbsp;Shivani Jain,&nbsp;Neha Grover,&nbsp;Kanishka Sharma,&nbsp;Manoj K. Sharma","doi":"10.1007/s13538-025-01775-0","DOIUrl":"10.1007/s13538-025-01775-0","url":null,"abstract":"<div><p>The investigation of various decay mechanisms, including evaporation residue (ER), intermediate mass fragments (IMF), heavy mass fragments (HMF), and fission fragments, has predominantly been observed to contribute at varying proportions. The observation has sparked our curiosity to delve deeper into the decay dynamics of few compound nuclei. Following compound nuclei from the lanthanide series, i.e., <span>(^{varvec{131}})</span>La<span>(^{varvec{*}})</span>, <span>(^{varvec{143}})</span>Pr<span>(^{varvec{*}})</span>, <span>(^{varvec{144}})</span>Nd<span>(^{varvec{*}})</span>, <span>(^{varvec{146}})</span>Sm<span>(^{varvec{*}})</span>, <span>(^{varvec{148,150}})</span>Gd<span>(^{varvec{*}})</span>, <span>(^{varvec{149}})</span>Eu<span>(^{varvec{*}})</span>, <span>(^{varvec{151,153}})</span>Tb<span>(^{varvec{*}})</span>, <span>(^{varvec{152,158}})</span>Dy<span>(^{varvec{*}})</span>, <span>(^{varvec{156,158,160,162,164,166}})</span>Er<span>(^{varvec{*}})</span>, <span>(^{varvec{157}})</span>Ho<span>(^{varvec{*}})</span>, <span>(^{varvec{161}})</span>Tm<span>(^{varvec{*}})</span>, <span>(^{varvec{162,164,166,168}})</span>Yb<span>(^{varvec{*}})</span> are chosen. We have used the Dynamical Cluster-decay Model (DCM), rooted in the Quantum Mechanical Fragmentation Theory (QMFT). This model offers a balanced treatment of various decay mechanisms, facilitating comprehension of compound nuclear dynamics. The calculated ER cross-sections, incorporating quadrupole <span>({varvec{beta }}_{varvec{2}})</span> deformation and optimal orientations, find decent agreement with the experimental data. The elongated orientation seems appropriate at below-barrier energies and the compact orientations at above-barrier energies. The fragmentation structure of compound nuclei reveals distinct decay fragments across mass regions (IMF, HMF, and fission fragments), emphasizing the role of nuclear magicity and deformation effects. A shift from broad shoulder structure to triple-humped mass distribution occurs as one proceeds from lower mass lanthanide to heavy mass lanthanide emphasizing the relative competition among decay fragments. Our study elucidates the fragmentation characteristics of lanthanide nuclei formed via heavy-ion-induced reactions, revealing the distinct preference of fragments in the decay process. Notably, deformations and orientation effects impart a discernible influence on the mass distribution. Proton and neutron magicity is evident in the analysis.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 4","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143930005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Two-State Stochastic Model of In Vivo Observations of Transcriptional Bursts","authors":"Luiz Guilherme S. da Silva,&nbsp;Romain Yvinec,&nbsp;Guilherme Prata,&nbsp;Varshant Dhar,&nbsp;John Reinitz,&nbsp;Alexandre F. Ramos","doi":"10.1007/s13538-025-01785-y","DOIUrl":"10.1007/s13538-025-01785-y","url":null,"abstract":"<div><p>In vivo measurements of gene expression in single cells show behavior that has been interpreted as stochastic bursts of transcription. In one case, these data have been interpreted as random ON–OFF transitions of the gene, but there is no experimental measurements or theoretical treatment of the number of transcripts produced at each burst event. In another case, such data have been interpreted to indicate multiple underlying transcriptional states. Here, we place both of these experiments in a common theoretical framework. In it, we couple two stochastic processes, one for synthesis of transcripts and one for their removal. Analysis of the resulting model is greatly aided by the existence of exact solutions of the master equation. We find the bursting limit of the exact solutions for our two-state gene expression model and show the occurrence of bursts of multiple sizes and durations by exact stochastic simulations. We also demonstrate that data from <i>Drosophila melanogaster</i> interpreted in terms of multiple underlying transcription states is fully compatible with underlying two-state ON or OFF transcriptional behavior. We discuss what experimental data is required to unambiguously determine the number of underlying promoter states.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 4","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13538-025-01785-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143925692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Statistical Method for A-RNA and B-DNA","authors":"Marco Zoli","doi":"10.1007/s13538-025-01787-w","DOIUrl":"10.1007/s13538-025-01787-w","url":null,"abstract":"<div><p>Nucleic acids have been regarded as stiff polymers with long-range flexibility and generally modeled using elastic rod models of polymer physics. Notwithstanding, investigations carried out over the past few years on single fragments of order <span>(sim 100)</span> base pairs have revealed remarkable flexibility properties at short scales and called for theoretical approaches that emphasize the role of the bending fluctuations at single sites along the molecule stack. Here, we review a three-dimensional mesoscopic Hamiltonian model which assumes a discrete representation of the double-stranded (ds) molecules at the level of the nucleotides. The model captures the fundamental local interactions between adjacent sugar-phosphate groups and the pairwise interactions between complementary base pair mates. A statistical method based on the path integral formalism sets the ensemble of the base pair breathing fluctuations which are included in the partition function and permits to derive the thermodynamics and the elastic response of single molecules to external forces. We apply the model to the computation of the twist-stretch relations for fragments of ds-DNA and ds-RNA, showing that the obtained opposite pattern (DNA overtwists whereas RNA untwists versus force) follows from the different structural features of the two helices. Moreover, we focus on the DNA stretching due to the confinement in nano-pores and, finally, on the computation of the cyclization probability of open ends molecules of <span>(sim 100)</span> base pairs under physiological conditions. The mesoscopic model shows a distinct advantage over the elastic rod model in estimating the molecule bendability at short-length scale.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 4","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143919037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}