Infinitely Many Solutions and a Ground-State Solution for Klein-Gordon Equation Coupled with Born-Infeld Theory

In this paper, we intend to consider a kind of nonlinear Klein-Gordon equation coupled with Born-Infeld theory. By using critical point theory and the method of Nehari manifold, we obtain two existing results of infinitely many high-energy radial solutions and a ground-state solution for this kind of system, which improve and generalize some related results in the literature.

Ground-state energy of beryllium atom with parameter perturbation method

We present a perturbation study of the ground-state energy of the beryllium atom by incorporating double parameters in the atom＇s Hamiltonian. The eigenvalue of the Hamiltonian is then solved with a double-fold perturbation scheme,where the spin-spin interaction of electrons from different shells of the atom is also considered. Calculations show that the obtained ground-state energy is in satisfactory agreement with experiment. It is found that the Coulomb repulsion of the inner-shell electrons enhances the effective nuclear charge seen by the outer-shell electrons, and the shielding effect of the outer-shell electrons to the nucleus is also notable compared with that of the inner-shell electrons.

Ground-state cooling based on a three-cavity optomechanical system in the unresolved-sideband regime

In the unresolved sideband regime,we propose a scheme for cooling mechanical resonator close to its ground state in a three-cavity optomechanical system,where the auxiliary cavities are indirectly connected with the mechanical resonator through standard optomechanical subsystem.The standard optomechanical subsystem is driven by a strong pump laser field.With the help of the auxiliary cavities,the heating process is suppressed and the cooling process of the mechanical resonator is enhanced.More importantly,the average phonon number is much less than 1 in a larger range.This means that the mechanical resonator can be cooled down to its ground state.All these interesting features will significantly promote the physical realization of quantum effects in multi-cavity optomechanical systems.

Modified Atomic Orbital Calculations of Energy of the(2s^(2)^(1)S)Ground-State,the(2p^(2)^(1)D);(3d^(2)^(1)G)and(4f^(2)^(1)l)Doubly Excited States of Helium Isoelectronic Sequence from H-to Ca^(18+)

We report in this paper the ground-state energy 2s2 1S and total energies of doubly excited states 2p2 1D, 3d2 1D, 4f2 1I of the Helium isoelectronic sequence from H- to Ca18+. Calculations are performed using the Modified Atomic Orbital Theory (MAOT) in the framework of a variational procedure. The purpose of this study required a mathematical development of the Hamiltonian applied to Slater-type wave function [1] combining with Hylleraas-type wave function [2]. The study leads to analytical expressions which are carried out under special MAXIMA computational program. This first proposed MAOT variational procedure, leads to accurate results in good agreement as well as with available other theoretical results than experimental data. In the present work, a new correlated wave function is presented to express analytically the total energies for the 2s2 1S ground state and each doubly 2p2 1D, 3d2 1D, 4f2 1I excited states in the He-like systems.The present accurate data may be a useful guideline for future experimental and theoretical studies in the (nl2) systems.

Experimental Observation of the Ground-State Geometric Phase of Three-Spin XY Model

The geometric phase has become a fundamental concept in many fields of physics since it was revealed. Recently, the study of the geometric phase has attracted considerable attention in the context of quantum phase transition, where the ground state properties of the system experience a dramatic change induced by a variation of an external parameter. In this work, we experimentally measure the ground-state geometric phase of the three-spin XY model by utilizing the nuclear magnetic resonance technique. The experimental results indicate that the geometric phase could be used as a fingerprint of the ground-state quantum phase transition of many-body systems.

Ground-state structure determination and mechanical properties of palladium seminitride

Combining first-principles calculations with the particle swarm optimization （PSO） algorithm, we have explored the ground-state structure of Pd2N, whose structure is in debate although it is the first synthesized binary platinum group nitride. The ground-state structure is predicted to be tetragonal with space group P^-4m2, which is energetically more favorable than the previously proposed orthorhombic Co2N-type structure. The stability is confirmed by the subsequent calculations on the phonon dispersion curves and elastic constants. Furthermore, the calculated mechanical properties indicate that Pd2N has low incompressibility and is a common hard material.

Ground-State Structure and Physical Properties of NB_2 Predicted from First Principles

Using the newly developed particle swarm optimization algorithm on crystal structural prediction, we predict a new class of boron nitride with stoicMometry of NB2 at ambient pressure, which belongs to the tetragonal 14m2 space group. Then, its structure, elastic properties, electronic structure, and chemical bonding are investigated by first-principles calculations with the density functional theory. The phonon calculation and elastic constants confirm that the predicted NB2 is dynamically and mechanically stable, respectively. The large bulk modulus, large shear modulus, large Young＇s modulus, and small Poisson＇s ratio show that the 14m2 NB2 should be a new superhard material with a calculated theoretical Vickers hardness value of 66 GPa. Further analysis on density of states and electron localization function demonstrate that the strong B B and 13 N covalent bonds are the main reason for its high hardness in 14m2 NB2.

A New Method for the Atomic Ground-State Energy in the Screened Coulomb Potential

The new method proposed recently by Friedberg,Lee and Zhao is applied to the derivation of the atomic ground-state energy with the inclusion of the screening effect.The present results are compared with those obtained in the pure Coulomb potential and by the variational approach.The overall good results are obtained with this new method.

The effects of the Dzyaloshinskii-Moriya interaction on the ground-state properties of the XY chain in a transverse field

The effects of the Dzyaloshinski-Moriya （DM） interaction on the ground-state properties of the anisotropic XY chain in a transverse field have been studied by means of correlation functions and entanglement. Different from the case without the DM interaction, the excitation spectra ek of this model are not symmetrical in the momentum space and are not always positive. As a result, besides the ferromagnetic （FM） and the paramagnetic （PM） phases, a gapless chiral phase is induced. In the chiral phase, the von Neumann entropy is proportional to log2 L （L is the length of a subchain） with the coefficient A ~ 1/3, which is the same as that of the XY chain in a transverse field without the DM interaction for 7 = 0 and 0 〈 h 〈 1. And in the vicinity of the critical point between the chiral phase and the FM （or PM） phase, the behaviors of the nearest- neighbor concurrence and its derivative are like those for the anisotropy transition.

Ground-State Energy and Entropy for One-Dimensional Heisenberg Chain with Alternating D-Term

We study the ground-state information of one-dimensional Heisenberg chain with alternating D-term. Given the ground-state phase diagram, the ground-state energy and the entanglement entropy are obtained by tensor-net work algorithm. The phase transition points are shown in the entanglement entropy figure. The results are agreed with the phase diagram.

Ground-State Phase Diagram of Transverse Spin-2 Ising Model with Longitudinal Crystal-Field

<正> The transverse spin-2 Ising ferromagnetic model with a longitudinal crystal-field is studied within themean-field theory based on Bogoliubov inequality for the Gibbs free energy.The ground-state phase diagram and thetricritical point are obtained in the transverse field Ω/zJ-longitudinal crystal D/zJ field plane.We find that there are thefirst order-order phase transitions in a very small range of D/zJ besides the usual first order-disorder phase transitionsand the second order-disorder phase transitions.

Theoretical Study of Geometric Structures for Ground-state Al_nC(n=2-7) Clusters

With the aid of the molecular orbital DMol3 program,the energetics and electronic structures of several AlnC（n = 2-7） configurations have been searched and calculated by improved minimum energy paths（MEPs） by setting ＂imaging product＂.A new high symmetry,supervalence isomer of Al5C cluster,i.e.,D5h-Al5C,at the local minimum in the MEPs is detected.Several parameters,such as binding energy,HOMO-LUMO energy gap,vertical electron detachment energy and electron affinity energy,are calculated to characterize and evaluate the stability of three Al5C configurations,i.e.,D5h-Al5C,Cs-Al5C and C1-Al5C.The results show that the D5h-Al5C cluster is the ground state structure instead of Cs-Al5C.Due to the formation of many central σ bonds after polymerizing for D5h-Al5C,the decrease of the energy for HOMO orbit results in more territory for HOMO electrons of dislocation effect,then the energy difference between HOMO and LUMO is increasing to enhance the stability of molecules to produce such supervalence structure of Al5C cluster.The configuration evolution between D5h-Al5C,Cs-Al5C and C1-Al5C and the synthesis preference in the mode of Al5 ＋ C → Al5C reveals that the Cs-Al5C and C1-Al5C con-figurations are permissive to coexist with D5h-Al5C structure in energetics.

Cell Evolutionary Algorithm: a New Optimization Method on Ground-State Energy of the Atomic

The purpose of this paper is to present a new general approach to solve ground-state energies of the double-electron systems in a uniform magnetic field, in which the basic element of evolution is the set in the solution space, rather than the point. The paper defines the Cell Evolutionary Algorithm, which implements such a view of the evolution mechanism. First, the optimal set in which the optimal solution may be obtained. Then this approach applies the embedded search method to get the optimal solution. We tested this approach on the atomic structure, and the results show that it can improve not only the efficiency but also the accuracy of the calculations as it relates to this specific problem.

Pressure-Induced Shifts of R, R＇, and B Line-Groups and Ground-State Zero-Field-Splitting of Ruby

By means of improved ligand-field theory, the 'pure electronic' presure-induced shifts (PS's) and the PS's due to electron-phonon interaction (EPI) of the R1, R2, B1, B2, B3, and R'3 lines and the ground-state zero-field-splitting of ruby have been uniformly calculated. The calculation results are in very good agreement with all the experimental data. At normal pressure, ruby is a crystal with very strong crystal field. Thus, the admixture of |t22 (3T1)e4T2> and |t3 2 2 E> bases in the wavefunction of R1 level of ruby is small at normal pressure, and it gradually decreases with increasing pressure, which causes the R1-line PS of ruby to monotonously red shift with approximate linearity. The combined effect of the pure electronic PS of R1 line and the PS of R1 line due to EPI gives rise to the total PS of R1 line. The analyses and comparisons among the features of R1-line PS's of three laser crystals (ruby, GSGG:Cr3+ and GGG:Cr3+ ) have been made, and the origin of their difference has been revealed.

Magnon squeezing enhanced ground-state cooling in cavity magnomechanics

Cavity magnomechanics has recently become a new platform for studying macroscopic quantum phenomena.The magnetostriction induced vibration mode of a large-size ferromagnet or ferrimagnet reaching its ground state represents a genuine macroscopic quantum state.Here we study the ground-state cooling of the mechanical vibration mode in a cavity magnomechanical system,and focus on the role of magnon squeezing in improving the cooling efficiency.The magnon squeezing is obtained by exploiting the magnon self-Kerr nonlinearity.We find that the magnon squeezing can significantly and even completely suppress the magnomechanical Stokes scattering.It thus becomes particularly useful in realizing ground-state cooling in the unresolved-sideband regime,where the conventional sideband cooling protocols become inefficient.We also find that the coupling to the microwave cavity plays only an adverse effect in mechanical cooling.This makes essentially the two-mode magnomechanical system(without involving the microwave cavity)a preferred system for cooling the mechanical motion,in which the magnon mode is established by a uniform bias magnetic field and a microwave drive field.

Unselective ground-state blockade of Rydberg atoms for implementing quantum gates

A dynamics regime of Rydberg atoms,unselective ground-state blockade(UGSB),is proposed in the context of Rydberg antiblockade(RAB),where the evolution of two atoms is suppressed when they populate in an identical ground state.UGSB is used to implement a SWAP gate in one step without individual addressing of atoms.Aiming at circumventing common issues in RAB-based gates including atomic decay,Doppler dephasing,and fluctuations in the interatomic coupling strength,we modify the RAB condition to achieve a dynamical SWAP gate whose robustness is much greater than that of the nonadiabatic holonomic one in the conventional RAB regime.In addition,on the basis of the proposed SWAP gates,we further investigate the implementation of a three-atom Fredkin gate by combining Rydberg blockade and RAB.The present work may facilitate to implement the RAB-based gates of strongly coupled atoms in experiment.

Fast-Convergent Solution of the Ground-State Energy for the He Atom

Recently Deng Conghao et al. proposed a new method for the direct solution of the many-body Schrdinger equation. Calculations based on this method for the ground-state energy of He indicated that the convergence of the hyperspherical harmonics (HH) expansion is slow and not satisfactory. A ground-state energy of-2.90328 a.u. was obtained in Ref.[2] with 361 HH and 4 GLF. In order to

Uranyl photocatalysis:precisely controlled oxidation of sulfides with ground-state oxygen

Sulfur-containing organic compounds such as sulfides,sulfoxides and sulfones,have played significant roles in the fields of organic synthesis,pharmaceuticals,and agrochemicals.The selective oxidation of the parent sulfides has been considered as one of the most straightforward methods for the construction of sulfoxides and sulfones.Therefore.

Detecting ground-state degeneracy in many-body systems through qubit decoherence

By coupling with a qubit, we demonstrate that qubit decoherence can unambiguously detect the occurrence of ground-state degeneracy in many-body systems. We first demonstrate universality using the two-band model. Consequently, several exemplifications, focused on topological condensed matter systems in one, two, and three dimensions, are presented to validate our proposal. The key point is that qubit decoherence varies significantly when energy bands touch each other at the Fermi surface. In addition, it can partially reflect the degeneracy inside the band. This feature implies that qubit decoherence can be used for reliable diagnosis of ground-state degeneracy.

Quantum coherence and ground-state phase transition in a four-chain Bose–Hubbard model

We study the quantum coherence and ground-state phase transition of a four-chain Bose–Hubbard model with the long-range interaction. In a special four-chain Bose–Hubbard model,i.e., each chain only has one optical potential, four types of the ground-state phases are discovered. The effects of the disorder, the on-site interaction and the long-range interaction on the quantum coherence are studied. For the system without the long-range interaction, the quantum coherence changes from one periodic oscillation to two periodic oscillations as the onsite interaction increases. By considering the long-range interaction, the quantum coherence goes back to one periodic oscillation again. The on-site interaction itself suppresses the quantum coherence, both the on-site interaction and long-range interaction together enhance the quantum coherence with the weak disorder. If the disorder strength is increased beyond a critical value,they start to suppress the quantum coherence. In a regular four-chain Bose–Hubbard model, i.e.,each chain has many optical potentials, the ground-state phase transitions are obtained by using the cluster Gutzwiller mean-field method. Exotic ground-state phases are found, i.e., superfluid phase, integer Mott insulator phase, supersolid phase and loophole insulator phase. The combination of the loophole insulator phase and the supersolid phase expands the lobes with the half-integer filling per site for the small ratio β = t_(‖)/t_(⊥).