Results 1 - 10 of 30
Results 1 - 10 of 30. Search took: 0.013 seconds
|Sort by: date | relevance|
[en] Efimov physics is drastically affected by the change of spatial dimensions. Efimov states occur in a three-dimensional (3D) environment, but disappear in two (2D) and one (1D) dimensions. In this paper, dedicated to the memory of Prof. Faddeev, we will review some recent theoretical advances related to the effect of dimensionality in the Efimov phenomenon considering three-boson systems interacting by a zero-range potential. We will start with a very ideal case with no physical scales (Rosa et al. in Phys Rev A 97:050701, 2018), passing to a system with finite energies in the Born–Oppenheimer (BO) approximation (Rosa et al. in J Phys B At Mol Opt Phys 52:025101, 2018) and finishing with a general system (Sandoval et al. in J Phys B At Mol Opt Phys 51:065004, 2018). The physical reason for the appearance of the Efimov effect is given essentially by two reasons which can be revealed by the BO approximation—the form of the effective potential is proportional to 1/R2 (R is the relative distance between the heavy particles) and its strength is smaller than the critical value given by −(D−2)2/4, where D is effective dimension. (author)
[en] A simple experiment to reveal the dimension of the pore space in sponges is proposed. This experiment is suitable for the first year of a physics or engineering course. The calculated dimension of the void space in a sponge of density 16 mg cm-3 was 2.948± 0.008
[en] This article is based on the notes written for a set of three lectures given in a school at the Max Planck Institute for the Physics of Complex Systems in October 2017 before the workshop “Critical Stability of Quantum Few-Body Systems”. The last part of the article includes the specific topic presented in the workshop related to the dimensional effects in three-body systems. These notes are primarily dedicated to the students and are only a tentative to show a technique, among many others, to solve problems in a very rich area of the contemporary physics—the Few-Body Physics. (author)
[en] For a system formed by three bosons interacting by a pairwise zero-range potential we show how the functional form of the asymptotic momentum distribution changes drastically when passing from bi (2D) to tridimensional (3D) regime, mainly affected by the absence/presence of the Efimov effect in 2D/3D. The spectator functions and the momentum distribution are calculated analytically for both regimes. (author)
[en] In this paper, we use the approximation of shallow water waves (Margaritondo G 2005 Eur. J. Phys. 26 401) to understand the behaviour of a tsunami in a variable depth. We deduce the shallow water wave equation and the continuity equation that must be satisfied when a wave encounters a discontinuity in the sea depth. A short explanation about how the tsunami hit the west coast of India is given based on the refraction phenomenon. Our procedure also includes a simple numerical calculation suitable for undergraduate students in physics and engineering
[en] We compute binding energies and root-mean-square radii for weakly bound systems of N=4 and 5 identical bosons. Ground and first excited states of an N-body system appear below the threshold for binding the system with N-1 particles. Their root-mean-square radii approach constants in the limit of weak binding. Their probability distributions are on average located in nonclassical regions of space which result in universal structures. Radii decrease with increasing particle number. The ground states for more than five particles are probably nonuniversal, whereas excited states may be universal.
[en] We present model results for the two-halo-neutron correlation functions, Cnn, for the dissociation process of light exotic nuclei modelled as two neutrons and a core. A minimum is predicted for Cnn as a function of the relative momentum of the two neutrons, pnn, due to the coherence of the neutrons in the halo and final state interaction. Studying the systems 14Be, 11Li, and 6He within this model, we show that the numerical asymptotic limit, Cnn→1, occurs only for pnn > or approx. 400 MeV/c, while such limit is reached for much lower values of pnn in an independent particle model as the one used in the analysis of recent experimental data. Our model is consistent with data once the experimental correlation function is appropriately normalized
[en] We show that the homogeneous Faddeev–Yakubovski formalism for the bound state of four identical bosons with zero-range interaction in the unitary limit (infinite two-body scattering length) presents scale invariance in the ultraviolet (UV) region. By resorting to an approximate form of the integral equations in the UV limit (considering exclusively an attractive pairwise zero-range interaction), we demonstrate that a pair of log-periodic solutions, with a cycle distinct from the three-boson one, exists with a four-body scale required to define the phase between them. (author)
[en] Within general characteristics of low-energy few-body systems, we revise some well-known correlations found in nuclear physics, and the properties of low-mass halo nuclei in a three-body neutron-neutron-core model. In this context, near the critical conditions for the occurrence of an Efimov state, we report some results obtained for the neutron-19C elastic scattering.