FORMATION AND STABILITY OF A STRONG-COUPLING LARGE BIPOLARON IN THE LIGHTLY DOPED CUPRATES

2005 ◽  
Vol 19 (06) ◽  
pp. 1061-1064
Author(s):  
E. DUSHANOV ◽  
S. DZHUMANOV
Keyword(s):  
Ground State ◽  
Stability Region ◽  
Continuum Model ◽  
Adiabatic Approximation ◽  
Three Dimensional ◽  
Dielectric Constants ◽  
Coulomb Correlation ◽  
Ground State Energies ◽  
Broad Region ◽  
The Continuum

The ground-state energies of large polaron Ep and bipolaron EB in three-dimensional lightly doped cuprates are calculated variationally taking into account the short- and long-range electron-phonon interactions and Coulomb correlation in the continuum model and adiabatic approximation. The binding energy of a large bipolaron and its stability region are determined as a function of the ratio of dielectric constants η = ε∞/ε0. It is found that the large bipolaron is stable in a broad region of η.

On the formation of cavitylike small-polaronic states in solid deuterium

1985 ◽  
Vol 63 (1) ◽  
pp. 94-98 ◽  
Author(s):  
S. K. Bose ◽  
J. D. Poll
Keyword(s):  
Ground State ◽  
Continuum Model ◽  
State Energy ◽  
Stark Shift ◽  
Localized State ◽  
Solid Deuterium ◽  
Vibrational Levels ◽  
Radiation Induced ◽  
Absorption Features ◽  
Ground State Energies

Certain infrared absorption features in tritiated as well as proton-irradiated samples of solid deuterium have been attributed to the formation of bubblelike electronic states localized in the lattice. These bubblelike states are shown to be energetically stable in the Wigner–Seitz model of the crystal and the gap between the ground-state energies in the bubble and the quasi-free states of the electron is calculated. An initial trapping of the electron by a vacancy is assumed in calculating the localized state energy. Calculations based on a continuum model of the solid yield the radius of such bubbles to close agreement with that obtained from the observed Stark shift of the vibrational levels of the neighbouring molecules due to the localized electrons. The model is used to interpret the radiation-induced absorption in proton-irradiated solid deuterium in the spectral region 4000–7500 cm−1.

scholarly journals Discrete-to-continuum modelling of weakly interacting incommensurate two-dimensional lattices

2018 ◽  
Vol 474 (2209) ◽  
pp. 20170612 ◽  
Author(s):  
Malena I. Español ◽  
Dmitry Golovaty ◽  
J. Patrick Wilber
Keyword(s):  
Continuum Model ◽  
Domain Walls ◽  
Three Dimensional ◽  
Variational Model ◽  
Dimensional System ◽  
Two Dimensional ◽  
Starting Point ◽  
Continuum Modelling ◽  
Three Dimensional System ◽  
The Continuum

In this paper, we derive a continuum variational model for a two-dimensional deformable lattice of atoms interacting with a two-dimensional rigid lattice. The starting point is a discrete atomistic model for the two lattices which are assumed to have slightly different lattice parameters and, possibly, a small relative rotation. This is a prototypical example of a three-dimensional system consisting of a graphene sheet suspended over a substrate. We use a discrete-to-continuum procedure to obtain the continuum model which recovers both qualitatively and quantitatively the behaviour observed in the corresponding discrete model. The continuum model predicts that the deformable lattice develops a network of domain walls characterized by large shearing, stretching and bending deformation that accommodates the misalignment and/or mismatch between the deformable and rigid lattices. Two integer-valued parameters, which can be identified with the components of a Burgers vector, describe the mismatch between the lattices and determine the geometry and the details of the deformation associated with the domain walls.

STUDY OF STRUCTURAL STABILITY OF WIGNER ELECTRON CRYSTAL

2000 ◽  
Vol 14 (17) ◽  
pp. 1767-1779 ◽  
Author(s):  
R. RAJESWARA PALANICHAMY ◽  
K. IYAKUTTI
Keyword(s):  
Ground State ◽  
Energy Surface ◽  
Three Dimensional ◽  
Present Calculation ◽  
Wannier Functions ◽  
Constant Energy ◽  
Bcc Lattice ◽  
The Stability ◽  
Ground State Energies ◽  
Electron Crystal

The ground state energies of the non-magnetic Wigner electron crystals corresponding to sc, bcc, fcc, diamond and perovskite structures are estimated and it is found that the bcc lattice still remains to be the stable known arrangement for three-dimensional Wigner electron crystal. Perovskite structure is not the stablest as claimed in a previous work, it is preferred only after fcc and sc. The stability is analysed taking different structures and assuming the possibility of the Wigner electrons having cubic or spherical constant energy surface, the region of occupation in momentum space, for a whole range of rs values (rs=20 to 200). The structure dependent Wannier functions, which give a proper localized representation for the Wigner electrons in the crystals are constructed and employed in the present calculation.

Analysis of Oxygen Exchange Between Arterioles and Surrounding Capillary-Perfused Tissue

1992 ◽  
Vol 114 (2) ◽  
pp. 227-231 ◽  
Author(s):  
R. Hsu ◽  
T. W. Secomb
Keyword(s):  
Theoretical Model ◽  
Flow Rate ◽  
Oxygen Transport ◽  
Continuum Model ◽  
Capillary Flow ◽  
Three Dimensional ◽  
Continuum Approach ◽  
Oxygen Loss ◽  
Tissue Region ◽  
The Continuum

A theoretical model is used to analyze oxygen transport in a three-dimensional tissue region containing an arteriole surrounded by an array of capillaries in planes perpendicular to the arteriole. Convective removal of oxygen from the vicinity of the arteriole by nearby capillaries is shown to increase diffusive oxygen loss from the arteriole. This effect depends on the locations of the capillaries, particularly those nearest to the arteriole. The arteriolar oxygen efflux is comparable to that predicted by a previous model which used a continuum approach, but the efflux does not increase with increasing perfusion as rapidly as predicted by the continuum model. Even a small capillary flow rate strongly influences the oxygen field surrounding the arteriole.

scholarly journals High-fidelity continuum modeling predicts avian voiced sound production

2020 ◽  
Vol 117 (9) ◽  
pp. 4718-4723
Author(s):  
Weili Jiang ◽  
Jeppe H. Rasmussen ◽  
Qian Xue ◽  
Ming Ding ◽  
Xudong Zheng ◽  
...  
Keyword(s):  
Continuum Model ◽  
Sound Production ◽  
Three Dimensional ◽  
High Fidelity ◽  
Terrestrial Vertebrates ◽  
Acoustic Performance ◽  
Tissue Material ◽  
Primary Form ◽  
The Continuum ◽  
Model Approach

Voiced sound production is the primary form of acoustic communication in terrestrial vertebrates, particularly birds and mammals, including humans. Developing a causal physics-based model that ultimately links descending vocal motor control to tissue vibration and sound requires embodied approaches that include realistic representations of voice physiology. Here, we first implement and then experimentally test a high-fidelity three-dimensional (3D) continuum model for voiced sound production in birds. Driven by individual-based physiologically quantifiable inputs, combined with noninvasive inverse methods for tissue material parameterization, our model accurately predicts observed key vibratory and acoustic performance traits. These results demonstrate that realistic models lead to accurate predictions and support the continuum model approach as a critical tool toward a causal model of voiced sound production.

VARIATIONAL COMPUTATIONS FOR EXCITONS IN QUANTUM DOTS: A QUANTUM MONTE CARLO STUDY

2011 ◽  
Vol 25 (01) ◽  
pp. 119-130
Author(s):  
A. YILDIZ ◽  
S. ŞAKİROĞLU ◽  
Ü. DOĞAN ◽  
K. AKGÜNGÖR ◽  
H. EPİK ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Monte Carlo ◽  
Ground State ◽  
Quantum Monte Carlo ◽  
Three Dimensional ◽  
Monte Carlo Study ◽  
Wave Functions ◽  
Monte Carlo Techniques ◽  
Oscillator Basis ◽  
Ground State Energies

A study of variational wave functions for calculation of the ground-state energies of excitons confined in a two-dimensional (2D) disc-like and three-dimensional (3D) spherical parabolic GaAs quantum dots (QDs) is presented. We have used four variational trial wave functions constructed as the harmonic-oscillator basis multiplied by different correlation functions. The proposed correlation function formed by including linear expansion in terms of Hylleraas-like coordinates to the Jastrow factor is able to capture nearly exactly the ground-state energies of 3D excitons, and it properly account for the results of 2D excitons. Quantum Monte Carlo techniques combined with the proposed wave function are a powerful tool for studying excitons in parabolic QDs.

Study on the Nonlinear Characteristic of a Rotor-Bearing System between the Continuum Model and Discrete Model

2009 ◽  
Vol 16-19 ◽  
pp. 851-855
Author(s):  
Chao Feng Li ◽  
Wei Sun ◽  
Chen Yi Liu ◽  
Bang Chun Wen
Keyword(s):  
Nonlinear Dynamic ◽  
Discrete Model ◽  
Continuum Model ◽  
Three Dimensional ◽  
Element Model ◽  
Significant Difference ◽  
Rotor Bearing ◽  
Comparison Of The Results ◽  
Bearing System ◽  
The Continuum

The nonlinear dynamic behavior of a rotor-bearing system is analyzed with its finite element model based on the analysis of the discrete model, with considering some other important influencing factors such as, material damping, gyroscopic effect, inertia distribution, shear effect and so on, which make the description of the system more embodiment avoiding the casualness of selection with system parameters. With the comparison of the results on the bifurcation map and three-dimensional spectrum, significant difference is appeared with the addition of the considered factors. It is suggested that the substitution of continuum model for the discrete ones can get more accurate and abundant results. Furthermore, these results can provide more accurate verification and reference for the experiment and nonlinear dynamic design of the complex rotor system.

Modeling of Ductile Damage and Fracture Behavior Based on Different Micromechanisms

2010 ◽  
Vol 20 (4) ◽  
pp. 558-577 ◽  
Author(s):  
Michael Brünig ◽  
Daniel Albrecht ◽  
Steffen Gerke
Keyword(s):  
Continuum Model ◽  
Failure Modes ◽  
Three Dimensional ◽  
Stress Triaxiality ◽  
Yield Condition ◽  
Lode Parameter ◽  
Material Parameters ◽  
Damage And Failure ◽  
Damage And Fracture ◽  
The Continuum

The article deals with the effect of stress triaxiality on the inelastic deformation behavior of aluminum alloys. The proposed continuum model takes into account stress triaxiality dependence of the yield condition as well as of the damage criterion and the fracture condition with different branches corresponding to various damage and failure modes depending on the stress triaxiality and the Lode parameter. Results of numerical cell simulations on the microscale are presented and corresponding identification of micromechanically motivated material parameters is discussed. Furthermore, numerical results of three-dimensional macromechanical finite element analyses are compared with experimental data obtained from smooth and pre-notched tension specimens. The analyses allow verification of the continuum model and identification of further material parameters.

Ultraviolet photodissociation dynamics of PCl3 at 235 nm: three-dimensional ion imaging and theoretical analysis

2021 ◽  
Author(s):  
Alexei Chichinin ◽  
Christof Maul ◽  
Karl-Heinz Gericke
Keyword(s):  
Theoretical Analysis ◽  
Ground State ◽  
Multiphoton Ionization ◽  
Three Dimensional ◽  
Ion Imaging ◽  
Ultraviolet Photodissociation

The photodissociation dynamics of PCl3 at 235 nm has been studied by monitoring ground state Cl(2P3/2) and spin-orbitally excited Cl(2P1/2) atoms by resonance enhanced multiphoton ionization(REMPI). Also, the PCl+n (n=0,1,2)...

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