Ground State Properties of a Local Sine-Gordon Model with Two Scatters

We investigate the local sine-Gordon model with two scatters by a variational method. The renormalization mass is calculated. It is found that there is an Ising-like phase transition, which is analogous in the global sineGordon model with two frequencies. The renormalization mass can be modulated by the distance between the two scatters.     

Ground State Properties of New Element Z=113 and Its Alpha Decay Chain

We investigate the ground state properties of the new element ^278 113 and of the α-decay chain with different models, where the new element Z=113 has been produced at RIKEN in Japan by cold-fusion reaction [Morita et al. J. Phys. Soc. Jpn. 73 (2004) 2593]. The experimental decay energies are reproduced by the deformed relativistic mean-field model, by the Skyrme-Hartree-Fock (SHF) model, and by the macroscopic-microscopic model.Theoretical half-lives also reasonably agree with the data. Calculations further show that prolate deformation is important for the ground states of the nuclei in the α-decay chain of ^278 113. The common points and differences among different models are compared and discussed.     

Ground State Properties¶of the Neutral Falicov–Kimball Model

We determine the large U ground states in the neutral two-dimensional Falicov-Kimball model for a sequence of densities converging to 0. For rational densities in (1/6,2/11) we show that the ground states exhibit a phase separation.     

Two Populations Mean-Field Monomer–Dimer Model

A two populations mean-field monomer–dimer model including both hard-core and attractive interactions between dimers is considered. The pressure density in the thermodynamic limit is proved to satisfy a variational principle. A detailed analysis is made in the limit of one population is much smaller than the other and a ferromagnetic mean-field phase transition is found.     

Ground State Energy of the One-Dimensional Discrete Random Schrödinger Operator with Bernoulli Potential

In this paper we show the that the ground state energy of the one-dimensional discrete random Schrödinger operator with Bernoulli potential is controlled asymptotically as the system size N goes to infinity by the random variable ? _N , the length the longest consecutive sequence of sites on the lattice with potential equal to zero. Specifically, we will show that for almost every realization of the potential the ground state energy behaves asymptotically as \({\frac{\pi^{2}}{(\ell_{N} +1)^{2}}} \) in the sense that the ratio of the quantities goes to one.     

Entanglement in the Ground State of an Isotropic Three-Qubit Transverse XY Chain with Energy Current

The ground state entanglement in an isotropic three-qubit transverse XY chain with energy current is analysed. A quantum phase transition from a no-energy-current phase to energy-current phase is found when the magnetic field changes. It has also been found that the ground state changes in company with the quantum phase transition.     

Ground—State Properties of a Local Sine—Gordon Model with Two Frequencies

The local sine-Gordon model with two frequencies is studied by a variational method.The renormalization mass and classical field path are calculated.We find an Ising-like phase transition,which is analogous in the global sine-Gordon model with two frequencies.A full phase diagram is given.     

The Gross–Pitaevskii Functional with a Random Background Potential and Condensation in the Single Particle Ground State

For discrete and continuum Gross–Pitaevskii energy functionals with a random background potential, we study the Gross–Pitaevskii ground state. We characterize a regime of interaction coupling when the Gross–Pitaevskii ground state and the ground state of the random background Hamiltonian asymptotically coincide.     

Gound State Properties of Nuclei in ^295118 α-Decay Chain

The properties of nuclei belonging to the α-decay chain of superheavy element ^295118 have been studied in the framework of axially deformed relativistic mean field （RMF） theory with the parameter set of NL-Z2 in the blocked BCS approximation. Some ground state properties such as binding energies, deformations, and α-decay energies Qα have been obtained and agree well with those from finite-range droplet model （FRDM）. The single-particle spectra of nuclei in ^295118 α-decay chain show that the shell gaps present obviously nucleon number dependence. The root-mean-square （rms） radii of proton, neutron and matter distributions change slowly from ^283112 to ^295118 but dramatically from ^279110 to ^283112, which may be due to the subshell closure at Z = 110 in ^279110. The α-decay half-lives in 295118 decay chain are evaluated by employing the cluster model and the generalized liquid drop model （GLDM）, and the overall agreement is found when they are compared with the known experimental data. The α-decay lifetimes obtained from the cluster model are slightly larger than those of GLDM ones. Finally, we predict the α-decay half-lives of Z=118, 116, 114, 112 isotopes using the cluster model and GLDM, which also indicate these two models can corroborate each other in studies on superheavy nuclei. The results from GLDM are always lower than those obtained from the cluster model.     

On the Ground State of Spin Systems with Orbital Degeneracy

In order to understand the properties of the spin system with orbital degeneracy,we first study the ground state of the SU(4) spin-orbital model on a square lattice.The mean-field results suggest that for a small Hund‘s interaction,the flavor liquid state is stable against the solid state,but with sufficient deviation from the SU(4) limit the long-range order may be attained in 2D system.Furthermore,we employ a variational approach to calculate the phase diagram of the ground state and the temperature-dependent susceptibility by taking into account the Hund‘s interaction and the anisotropy in orbital wavefunctions.Finally,the implications for the experimental observations on the material,LiNiO2,are discussed.     

Ground State Properties for Bose-Condensed Gas in Anisotropic Traps

Based on the energy functional and variational method, we present a new method to investigate the ground state properties for a weakly interacting Bose-condensed gas in an anisotropic harmonic trap at zero temperature. With this method we are able to find the analytic expression of the ground-state wavefunction and to explore the relevant quantities, such as energy, chemical potential, and the aspect ratio of the velocity distribution. These results agree well with previous ground state numerical solutions of the Gross-Pitaevskii equation given by Dalfovo et al. [Phys. Rev. A 53 （1996） 2477] This new method is simple compared to other methods used to solve numerically the Gross-Pitaevskii equation, and one can obtain analytic and reliable results.     

The Properties of the Polarons’ Ground State in Coupling Spherical Quantum Dots

International Journal of Theoretical Physics - Investigations on the properties of polarons in coupling quantum dots (QDs) are useful for the designs of quantum devices and applications of QDs....     

Ground State of a Two-Electron Quantum Dot with a Gaussian Confining Potential

We investigate the ground-state properties of a two-dimensional two-electron quantum dot with a Gaussian confining potential under the influence of perpendicular homogeneous magnetic field. Calculations are carried out by using the method of numerical diagonalization of Hamiltonian matrix within the effective-mass approximation. A ground-state behaviour （singlet→triplet state transitions） as a function of the strength of a magnetic field has been found. It is found that the dot radius R of the Gaussian potential is important for the ground-state transition and the feature of ground-state for the Gaussian potential quantum dot （QD）, and the parabolic potential QDs are similar when R is larger. The larger the quantum dot radius, the smaller the magnetic field for the singlet-triplet transition of the ground-state of two interacting electrons in the Gaussian quantum dot.     

Ground State Energy of Unitary Fermion Gas with the Thomson Problem Approach

The dimensionless universal coefficient ε defines the ratio of the unitary fermions energy density to that for the ideal non-interacting ones in the non-relativistic limit with T = 0. The classical Thomson problem is taken as a nonperturbative quantum many-body arm to address the ground state energy including the low energy nonlinear quantum fluctuation/correlation effects. With the relativistic Dirac continuum field theory formalism, the concise expression for the energy density functional of the strongly interacting limit fermions at both finite temperature and density is obtained. Analytically, the universal factor is calculated to be ε= 4/9. The energy gap is△= 5/8k^2f/（2m）.     

ThermoElectric Transport Properties of a Chain of Quantum Dots with Self-Consistent Reservoirs

We introduce a model for charge and heat transport based on the Landauer-Büttiker scattering approach. The system consists of a chain of N quantum dots, each of them being coupled to a particle reservoir. Additionally, the left and right ends of the chain are coupled to two particle reservoirs. All these reservoirs are independent and can be described by any of the standard physical distributions: Maxwell-Boltzmann, Fermi-Dirac and Bose-Einstein. In the linear response regime, and under some assumptions, we first describe the general transport properties of the system. Then we impose the self-consistency condition, i.e. we fix the boundary values (T _L,μ _L) and (T _R,μ _R), and adjust the parameters (T _i ,μ _i ), for i=1,…,N, so that the net average electric and heat currents into all the intermediate reservoirs vanish. This condition leads to expressions for the temperature and chemical potential profiles along the system, which turn out to be independent of the distribution describing the reservoirs. We also determine the average electric and heat currents flowing through the system and present some numerical results, using random matrix theory, showing that these currents are typically governed by Ohm and Fourier laws.     

Systematic Calculation on Ground State Properties of Even-even Superheavy Nuclei Using Relativistic Mean Field Theory

In recent years the discovery of Super Heavy Element (SHE) with atomic number Z=108～116 has opened up a new era of research in nuclear physics, however, the extreme difficulties to synthesize SHE greatly restrict the experimental studies on it, so that the theoretical studies are very important. The Relativistic Mean Field theory (RMF) is proved to be a simple and successful theory due to its great success in describing the bulk properties at the β-stable valley, as well as nuclei far from the β-stable line, and gives good predictions for nuclei far beyond the end of the known periodic table. In the framework of RMF we have calculated the properties on SHN such as the binding energy, the deformation, single and double neutron separation energy, and the a-decay half-life and so on for nuclei Z=108～114 and N=156～190. The axial deformations considered by using the expansion of harmonic oscillator basis. The Lagrangian wc have used is as the following form:     

Ferrimagnetic Properties of Bond Dilution Mixed Blume-Capel Model with Random Single-Ion Anisotropy

We study the ferrimagnetic properties of spin 1/2 and spin-1 systems by means of the effective field theory. The system is considered in the framework of bond dilution mixed Blume-Capel mode/ （BCM） with random single-ion anisotropy. The investigation of phase diagrams and magnetization curves indicates the existence of induced magnetic ordering and single or multi-compensation points. Special emphasis is placed on the influence of bond dilution and random single-ion anisotropy on normal or induced magnetic ordering states and single or multi-compensation points. Normal magnetic ordering states take on new phase diagrams with increasing randomness （bond and anisotropy）, while anisotropy induced magnetic ordering states are always occurrence no matter whether concentration of anisotropy is large or small. Existence and disappearance of compensation points rely strongly on bond dilution and random singleion anisotropy. Some results have not been revealed in previous papers and predicted by Néel theory of ferrimagnetism.