scholarly journals Kink–antikink scattering-induced breathing bound states and oscillons in a parametrized ϕ4 model

2020 ◽  
pp. 2150015
Author(s):  
F. Naha Nzoupe ◽  
Alain M. Dikandé ◽  
C. Tchawoua
Keyword(s):  
Scalar Field ◽  
Potential Barrier ◽  
Bound States ◽  
Phonon Scattering ◽  
Bistable System ◽  
Main Determinant ◽  
Text Field ◽  
Standard Picture ◽  
Low Amplitude ◽  
Double Well Potential

Recent studies have emphasized the important role that a shape deformability of scalar-field models pertaining to the same class with the standard [Formula: see text] field, can play in controlling the production of a specific type of breathing bound states so-called oscillons. In the context of cosmology, the built-in mechanism of oscillons suggests that they can affect the standard picture of scalar ultra-light dark matter. In this paper, kink scatterings are investigated in a parametrized model of bistable system admitting the classical [Formula: see text] field as an asymptotic limit, with focus on the formation of long-lived low-amplitude almost harmonic oscillations of the scalar field around a vacuum. The parametrized model is characterized by a double-well potential with a shape-deformation parameter that changes only the steepness of the potential walls, and hence the flatness of the hump of the potential barrier, leaving unaffected the two degenerate minima and the barrier height. It is found that the variation of the deformability parameter promotes several additional vibrational modes in the kink-phonon scattering potential, leading to suppression of the two-bounce windows in kink–antikink scatterings and the production of oscillons. Numerical results suggest that the anharmonicity of the potential barrier, characterized by a flat barrier hump, is the main determinant factor for the production of oscillons in double-well systems.

scholarly journals Noninertial effects on a scalar field in a spacetime with a magnetic screw dislocation

2019 ◽  
Vol 79 (10) ◽  
Author(s):  
Ricardo L. L. Vitória
Keyword(s):  
Scalar Field ◽  
Screw Dislocation ◽  
Bound States ◽  
Charged Scalar ◽  
Wall Potential ◽  
Noninertial Effects ◽  
Klein Gordon ◽  
Coulomb Type ◽  
Charged Scalar Field ◽  
Type Potential

Abstract We investigate rotating effects on a charged scalar field immersed in spacetime with a magnetic screw dislocation. In addition to the hard-wall potential, which we impose to satisfy a boundary condition from the rotating effect, we insert a Coulomb-type potential and the Klein–Gordon oscillator into this system, where, analytically, we obtain solutions of bound states which are influenced not only by the spacetime topology, but also by the rotating effects, as a Sagnac-type effect modified by the presence of the magnetic screw dislocation.

Quasilinear Scalar Field Equations Involving Critical Sobolev Exponents and Potentials Vanishing at Infinity

2018 ◽  
Vol 61 (3) ◽  
pp. 705-733 ◽  
Author(s):  
Athanasios N. Lyberopoulos
Keyword(s):  
Scalar Field ◽  
Weak Solutions ◽  
Bound States ◽  
Critical Sobolev Exponent ◽  
Field Equations ◽  
Critical Sobolev Exponents ◽  
Sobolev Exponent ◽  
Image Position ◽  
Scalar Field Equations

AbstractWe are concerned with the existence of positive weak solutions, as well as the existence of bound states (i.e. solutions inW1,p(ℝN)), for quasilinear scalar field equations of the form$$ - \Delta _pu + V(x) \vert u \vert ^{p - 2}u = K(x) \vert u \vert ^{q - 2}u + \vert u \vert ^{p^ * - 2}u,\qquad x \in {\open R}^N,$$where Δpu: =div(|∇u|p−2∇u), 1 <p<N,p*: =Np/(N−p) is the critical Sobolev exponent,q∈ (p, p*), whileV(·) andK(·) are non-negative continuous potentials that may decay to zero as |x| → ∞ but are free from any integrability or symmetry assumptions.

Bound states of relativistic particles in the generalized symmetrical double-well potential

2005 ◽  
Vol 337 (3) ◽  
pp. 189-196 ◽  
Author(s):  
Xing-Qiang Zhao ◽  
Chun-Sheng Jia ◽  
Qiu-Bo Yang
Keyword(s):  
Bound States ◽  
Double Well Potential ◽  
Relativistic Particles

Three- and four-particle bound states in scalar field theory

1986 ◽  
Vol 33 (8) ◽  
pp. 2316-2318 ◽  
Author(s):  
Jurij W. Darewych ◽  
Marko Horbatsch ◽  
Roman Koniuk
Keyword(s):  
Field Theory ◽  
Scalar Field ◽  
Bound States ◽  
Scalar Field Theory

Stationary bound states of massless scalar fields around black holes and black hole analogues

2015 ◽  
Vol 24 (09) ◽  
pp. 1542018 ◽  
Author(s):  
Carolina L. Benone ◽  
Luís C. B. Crispino ◽  
Carlos A. R. Herdeiro ◽  
Eugen Radu
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Spatial Distribution ◽  
Scalar Field ◽  
Bound States ◽  
Neumann Boundary ◽  
Mass Term ◽  
Scalar Fields ◽  
Massless Scalar ◽  
Field System

We discuss stationary bound states, a.k.a. clouds, for a massless test scalar field around Kerr black holes (BHs) and spinning acoustic BH analogues. In view of the absence of a mass term, the trapping is achieved via enclosing the BH — scalar field system in a cavity and imposing Dirichlet or Neumann boundary conditions. We discuss the variation of these bounds states with the discrete parameters that label them, as well as their spatial distribution, complementing results in our previous work [C. L. Benone, L. C. B. Crispino, C. Herdeiro and E. Radu, Phys. Rev. D91 (2015) 104038].

scholarly journals Segregation of NiTe2 and NbTe2 in p-Type Thermoelectric Bi0.5Sb1.5Te3 Alloys for Carrier Energy Filtering Effect by Melt Spinning

2021 ◽  
Vol 11 (3) ◽  
pp. 910
Author(s):  
Hyun-Sik Kim ◽  
TaeWan Kim ◽  
Jiwoo An ◽  
Dongho Kim ◽  
Ji Hoon Jeon ◽  
...  
Keyword(s):  
Potential Barrier ◽  
Power Factor ◽  
Melt Spinning ◽  
Phonon Scattering ◽  
Synthesis Process ◽  
Secondary Phases ◽  
Spinning Process ◽  
Interface Potential ◽  
Filtering Effect ◽  
P Type

The formation of secondary phases of NiTe2 and NbTe2 in p-type Bi0.5Sb1.5Te3 thermoelectric alloys was investigated through in situ phase separation by using the melt spinning process. Adding stoichiometric Ni, Nb, and Te in a solid-state synthesis process of Bi0.5Sb1.5Te3, followed by rapid solidification by melt spinning, successfully segregated NiTe2 and NbTe2 in the Bi0.5Sb1.5Te3 matrix. Since heterointerfaces of Bi0.5Sb1.5Te3 with NiTe2 and NbTe2 form potential barriers of 0.26 and 0.08 eV, respectively, a low energy carrier filtering effect can be expected; higher Seebeck coefficients and power factors were achieved for Bi0.5Sb1.5Te3(NiTe2)0.01 (250 μV/K and 3.15 mW/mK2), compared to those of Bi0.5Sb1.5Te3 (240 μV/K and 2.69 mW/mK2). However, there was no power factor increase for NbTe2 segregated samples. The decrease in thermal conductivity was seen due to the possible additional phonon scattering by the phase segregations. Consequently, zT at room temperature was enhanced to 0.98 and 0.94 for Bi0.5Sb1.5Te3(NiTe2)0.01 and Bi0.5Sb1.5Te3(NbTe2)0.01, respectively, compared to 0.79 for Bi0.5Sb1.5Te3. The carrier filtering effect induced by NiTe2 segregations with an interface potential barrier of 0.26 eV effectively increased the Seebeck coefficient and power factor, thus improving the zT of p-type Bi0.5Sb1.5Te3, while the interface potential barrier of 0.08 eV of NbTe2 segregation appeared to be too small to induce an effective carrier filtering effect.

scholarly journals High frequency atomic tunneling yields ultralow and glass-like thermal conductivity in chalcogenide single crystals

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Bo Sun ◽  
Shanyuan Niu ◽  
Raphael P. Hermann ◽  
Jaeyun Moon ◽  
Nina Shulumba ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Single Crystals ◽  
High Frequency ◽  
Phonon Scattering ◽  
Fundamental Interest ◽  
Monotonic Trend ◽  
Tunneling System ◽  
Anharmonic Interactions ◽  
Double Well Potential ◽  
Microscopic Origin

AbstractCrystalline solids exhibiting glass-like thermal conductivity have attracted substantial attention both for fundamental interest and applications such as thermoelectrics. In most crystals, the competition of phonon scattering by anharmonic interactions and crystalline imperfections leads to a non-monotonic trend of thermal conductivity with temperature. Defect-free crystals that exhibit the glassy trend of low thermal conductivity with a monotonic increase with temperature are desirable because they are intrinsically thermally insulating while retaining useful properties of perfect crystals. However, this behavior is rare, and its microscopic origin remains unclear. Here, we report the observation of ultralow and glass-like thermal conductivity in a hexagonal perovskite chalcogenide single crystal, BaTiS3, despite its highly symmetric and simple primitive cell. Elastic and inelastic scattering measurements reveal the quantum mechanical origin of this unusual trend. A two-level atomic tunneling system exists in a shallow double-well potential of the Ti atom and is of sufficiently high frequency to scatter heat-carrying phonons up to room temperature. While atomic tunneling has been invoked to explain the low-temperature thermal conductivity of solids for decades, our study establishes the presence of sub-THz frequency tunneling systems even in high-quality, electrically insulating single crystals, leading to anomalous transport properties well above cryogenic temperatures.

Long-time behaviour of an initially localized quantum state

2008 ◽  
Vol 86 (11) ◽  
pp. 1251-1255
Author(s):  
M R.A. Shegelski ◽  
J Hnybida
Keyword(s):  
Potential Barrier ◽  
Quantum State ◽  
Bound States ◽  
Potential Well ◽  
Time Behaviour ◽  
Wide Audience ◽  
Simple Method ◽  
Long Time Behaviour ◽  
Long Time

The long-time behaviour of an initially localized quantum state is shown to decay as t –3/2 for any potential well and any potential barrier. An example using a delta barrier is also calculated fully. The result is general yet the proof uses a simple method that is clear and accessible to a wide audience. The effect of bound states on the long-time behaviour is also considered. When there are bound states the long-time behaviour is different.PACS Nos.: 03.65.–w, 03.65.Xp

Stationary configurations around charged rotating black holes

2016 ◽  
Vol 25 (09) ◽  
pp. 1641012
Author(s):  
Carolina L. Benone
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Scalar Field ◽  
Bound States ◽  
Scalar Fields ◽  
Analytic Solutions ◽  
Massive Scalar ◽  
Massive Scalar Field ◽  
Rotating Black Holes ◽  
Specific Frequency

Scalar fields can form real bound states around black holes for a specific frequency. In this work, we review the case of a charged and massive scalar field around a charged rotating black hole, in order to find these bound states. We analyze the behavior of these solutions for different parameters and also comment on analytic solutions for certain regimes.

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