Few-Body SystemsPub Date : 2024-10-26DOI: 10.1007/s00601-024-01967-5
Abdullah Guvendi, Abdelmalek Boumali
{"title":"Exploring Statistical Properties of Fermion-Antifermion Pairs in Magnetized Spacetime Under Non-zero Cosmology","authors":"Abdullah Guvendi, Abdelmalek Boumali","doi":"10.1007/s00601-024-01967-5","DOIUrl":"10.1007/s00601-024-01967-5","url":null,"abstract":"<div><p>This research investigates the complex statistical behavior of fermion-antifermion pairs within a (2+1)-dimensional magnetized Bonnor-Melvin background affected by non-zero cosmological conditions. The Bonnor-Melvin magnetic universe model, known for its cylindrical symmetry, preserves the invariance of quantum field dynamics under Lorentz boosts along the <span>(z)</span>-axis. This framework facilitates the examination of (2+1)-dimensional scenarios, where the corresponding spacetime background is identified as the Bonnor-Melvin magnetic 2+1+0-brane solution within the realm of gravity coupled with nonlinear electrodynamics. Initially, the precise energy spectra of these pairs are summarized using an analytical solution derived from the fully covariant two-body Dirac equation. Subsequently, the statistical properties inherent in these pair formations are investigated. These findings may illuminate the interplay among magnetic fields, spacetime geometry, and the cosmological constant, thereby enhancing our comprehension of the fundamental behaviors of fermions amidst intricate cosmological conditions. It is anticipated that this investigation could offer new insights into the statistical attributes of fermion-antifermion systems. All thermal characteristics, including free energy, total energy, entropy, and specific heat, have been computed. The impact of diverse factors, such as magnetic fields, spacetime geometry, and the cosmological constant, on these characteristics has been scrutinized.</p></div>","PeriodicalId":556,"journal":{"name":"Few-Body Systems","volume":"65 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142518908","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}
Few-Body SystemsPub Date : 2024-10-19DOI: 10.1007/s00601-024-01963-9
Bernard Faulend, Jan Dragašević
{"title":"Tunnelling of a Composite Particle in Presence of a Magnetic Field","authors":"Bernard Faulend, Jan Dragašević","doi":"10.1007/s00601-024-01963-9","DOIUrl":"10.1007/s00601-024-01963-9","url":null,"abstract":"<div><p>We present a simple model of composite particle tunnelling through a potential barrier in presence of a (pseudo)magnetic field. The exact numerical solution of the problem is provided and the applicability to real physical systems is discussed. When the magnetic field is present some new qualitative features of the transmission spectrum are observed, compared to the previously studied composite particle tunnelling with no magnetic field. Splitting of energy levels in a magnetic field leads to splitting of transmission probability resonances, which are a generic feature of composite particle tunnelling. Magnetic field also induces precession of spin on the Bloch sphere, that can be used as a Larmor clock for measuring tunnelling time.</p></div>","PeriodicalId":556,"journal":{"name":"Few-Body Systems","volume":"65 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142451071","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}
Few-Body SystemsPub Date : 2024-10-09DOI: 10.1007/s00601-024-01961-x
Brady J. Martin, W. N. Polyzou
{"title":"Perturbation Theory of the Continuous Spectrum in the Theory of Nuclear Reactions","authors":"Brady J. Martin, W. N. Polyzou","doi":"10.1007/s00601-024-01961-x","DOIUrl":"10.1007/s00601-024-01961-x","url":null,"abstract":"<div><p>Nuclear reactions are complex, with a large number of possible channels. Understanding how different channels contribute to a given reaction is investigated by perturbing the continuous spectrum. Tools are developed to investigate reaction mechanisms by identifying the contributions from each reaction channel. Cluster decomposition methods, along with the spectral theory of proper subsystem problems, is used to identify the part of the nuclear Hamiltonian responsible for scattering into each channel. The result is an expression of the nuclear Hamiltonian as a sum over all scattering channels of channel Hamiltonians. Each channel Hamiltonian is constructed from solutions of proper subsystem problems. Retaining any subset of channel Hamiltonians results in a truncated Hamiltonian where the scattering wave functions for the retained channels differ from the wave functions of the full Hamiltonian by <i>N</i>-body correlations. The scattering operator for the truncated Hamiltonian satisfies an optical theorem in the retained channels. Because different channel Hamiltonians do not commute, how they interact determines their contribution to the full dynamics.</p></div>","PeriodicalId":556,"journal":{"name":"Few-Body Systems","volume":"65 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142411081","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}
Few-Body SystemsPub Date : 2024-09-26DOI: 10.1007/s00601-024-01959-5
G. Bougas, S. I. Mistakidis, P. Giannakeas
{"title":"Density Effects on the Interferometry of Efimov States by Modulating Magnetic Fields","authors":"G. Bougas, S. I. Mistakidis, P. Giannakeas","doi":"10.1007/s00601-024-01959-5","DOIUrl":"10.1007/s00601-024-01959-5","url":null,"abstract":"<div><p>Dynamical association of Efimov trimers in thermal gases by means of modulated magnetic fields has proven very fruitful in determining the binding energy of trimers. The latter was extracted from the number of remaining atoms, which featured oscillatory fringes stemming from the superposition of trimers with atom-dimers. Subsequent theoretical investigations utilizing the time-dependent three-body problem revealed additional association mechanisms, manifested as superpositions of the Efimov state with the trap states and the latter with atom-dimers. The three atoms were initialized in a way to emulate a thermal gas with uniform density. Here, this analysis is extended by taking into account the effects of the density profile of a semi-classical thermal gas. The supersposition of the Efimov trimer with the first atom-dimer remains the same, while the frequencies of highly oscillatory fringes shift to lower values. The latter refer to the frequencies of trimers and atom-dimers in free space since the density profile smears out the contribution of trap states.</p></div>","PeriodicalId":556,"journal":{"name":"Few-Body Systems","volume":"65 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142414077","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}
Few-Body SystemsPub Date : 2024-09-24DOI: 10.1007/s00601-024-01960-y
Axel Schulze-Halberg
{"title":"Approximate Bound States for the Dunkl–Schrödinger Equation with Symmetrized Hulthén Potential","authors":"Axel Schulze-Halberg","doi":"10.1007/s00601-024-01960-y","DOIUrl":"10.1007/s00601-024-01960-y","url":null,"abstract":"<div><p>We construct approximate bound state solutions to the one-dimensional Schrödinger equation within the Dunkl formalism for a symmetrized Hulthén potential. Our method is based on reducing the governing equation to conventional Schrödinger form, such that an approximation to an inverse quadratic term becomes applicable. Conditions for computing stationary energies, as well as for establishing boundedness and normalizability of our solutions are discussed.</p></div>","PeriodicalId":556,"journal":{"name":"Few-Body Systems","volume":"65 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142413506","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}
Few-Body SystemsPub Date : 2024-09-23DOI: 10.1007/s00601-024-01956-8
J. Alejandro Alfaro, L. X. Gutiérrez-Guerrero, Luis Albino, Alfredo Raya
{"title":"Perturbative Analysis of the Three Gluon Vertex in Different Gauges at One-Loop","authors":"J. Alejandro Alfaro, L. X. Gutiérrez-Guerrero, Luis Albino, Alfredo Raya","doi":"10.1007/s00601-024-01956-8","DOIUrl":"10.1007/s00601-024-01956-8","url":null,"abstract":"<div><p>In this study, we present a perturbative analysis of the three-gluon vertex for a kinematical symmetric configuration in dimensions <span>(n=4-2epsilon )</span> and different covariant gauges. Our study can describe the form factors of the three gluon vertex in a wide range of momentum. We employ a momentum subtraction scheme to define the renormalized vertex. We give an in-depth review of three commonly used vector representations for the vertex, and explicitly show the expressions to change from one representation to the other. Although our estimates are valid only in the perturbative regime, we extend our numerical predictions to the infrared domain and show that in <span>(n=4)</span> some nonperturbative properties are qualitatively present already at perturbation theory. In particular, we find a critical gauge above which the leading form factor displays the so-called zero crossing. We contrast our findings to those of other models and observe a fairly good agreement. \u0000</p></div>","PeriodicalId":556,"journal":{"name":"Few-Body Systems","volume":"65 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142413384","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}
Few-Body SystemsPub Date : 2024-09-23DOI: 10.1007/s00601-024-01957-7
Y. Suzuki
{"title":"Correction to: Calculable Microscopic Theory for (^{12})C((alpha , gamma ))(^{16})O Cross Section near Gamow Window","authors":"Y. Suzuki","doi":"10.1007/s00601-024-01957-7","DOIUrl":"10.1007/s00601-024-01957-7","url":null,"abstract":"","PeriodicalId":556,"journal":{"name":"Few-Body Systems","volume":"65 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142413345","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}
Few-Body SystemsPub Date : 2024-09-20DOI: 10.1007/s00601-024-01958-6
Z. Bakhshi, S. Khoshdooni, H. Rahmati
{"title":"Algebraic Approach to a Special Four-Body Solvable Model","authors":"Z. Bakhshi, S. Khoshdooni, H. Rahmati","doi":"10.1007/s00601-024-01958-6","DOIUrl":"10.1007/s00601-024-01958-6","url":null,"abstract":"<div><p>A special four-body quantum model in one dimension with a discrete spectrum was introduced, including harmonic oscillator and three-body interaction potentials. After reducing one degree of freedom by using the Jacobian transformation in the center of mass, the desired Hamiltonian is examined in spherical coordinate with three degrees of freedom. To investigate this model algebraically, using the gauge rotation with the ground state wave function, the relation between the Hamiltonian and the generators of <span>(sl(3, {mathbb {R}}))</span> and <span>(sl(2, {mathbb {R}}))</span> Lie algebras is examined. Finally, this algebraic form helps us to get the Hamiltonian eigenvalues.</p></div>","PeriodicalId":556,"journal":{"name":"Few-Body Systems","volume":"65 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142412741","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}
Few-Body SystemsPub Date : 2024-09-20DOI: 10.1007/s00601-024-01951-z
Cyrille Chevalier, Selma Youcef Khodja
{"title":"Three-Body Forces in Oscillator Bases Expansion","authors":"Cyrille Chevalier, Selma Youcef Khodja","doi":"10.1007/s00601-024-01951-z","DOIUrl":"10.1007/s00601-024-01951-z","url":null,"abstract":"<div><p>The oscillator bases expansion stands as an efficient approximation method for the time-independent Schrödinger equation. The method, originally formulated with one non-linear variational parameter, can be extended to incorporate two such parameters. It handles both non- and semi-relativistic kinematics with generic two-body interactions. In the current work, focusing on systems of three identical bodies, the method is generalised to include the management of a given class of three-body forces. The computational cost of this generalisation proves to not exceed the one for two-body interactions. The accuracy of the generalisation is assessed by comparing with results from Lagrange mesh method and hyperspherical harmonic expansions. Extensions for systems of <i>N</i> identical bodies and for systems of two identical particles and one distinct are also discussed.</p></div>","PeriodicalId":556,"journal":{"name":"Few-Body Systems","volume":"65 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142412740","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}
Few-Body SystemsPub Date : 2024-09-16DOI: 10.1007/s00601-024-01954-w
J. van de Kraats, S. J. J. M. F. Kokkelmans
{"title":"Accurate Simulation of Efimov Physics in Ultracold Atomic Gases with Realistic Three-Body Multichannel Interactions","authors":"J. van de Kraats, S. J. J. M. F. Kokkelmans","doi":"10.1007/s00601-024-01954-w","DOIUrl":"10.1007/s00601-024-01954-w","url":null,"abstract":"<div><p>We give a detailed and self-contained description of a recently developed theoretical and numerical method for the simulation of three identical bosonic alkali-metal atoms near a Feshbach resonance, where the Efimov effect is induced. The method is based on a direct construction of the off-shell two-body transition matrix from exact eigenfunctions of the embedded two-body Hamiltonians, obtained using realistic parameterizations of the interaction potentials which accurately reproduce the molecular energy levels. The transition matrix is then inserted into the appropriate three-body integral equations, which may be efficiently solved on a computer. We focus especially on the power of our method in including rigorously the effects of multichannel physics on the three-body problem, which are usually accounted for only by various approximations. We demonstrate the method for <sup>7</sup>Li, where we recently showed that a correct inclusion of this multichannel physics resolves the long-standing disagreement between theory and experiment regarding the Efimovian three-body parameter. We analyze the Efimovian enhancement of the three-body recombination rate on both sides of the Feshbach resonance, revealing strong sensitivity to the spin structure of the model thus indicating the prevalence of three-body spin-exchange physics. Finally, we discuss an extension of our methodology to the calculation of three-body bound-state energies.</p></div>","PeriodicalId":556,"journal":{"name":"Few-Body Systems","volume":"65 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00601-024-01954-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260257","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}