Yunchuan Dai

THE FRIEDMANN EQUATION IN MODIFIED ENTROPY-AREA RELATION FROM ENTROPY FORCE

According to the formal holographic principle, a modification to the assumption of holographic principle in Verlinders investigation of entropy force is obtained. A more precise relation between entropy and area in the holographic system is proposed. With the entropy corrections to the area-relation, we derivate Newtons laws and Einstein equation with a static spherically symmetric holographic screen. Furthermore, we derived the correction terms to the modified Friedmann equation of the FRW universe starting from the holographic principle and the Debye model.

Quantum Monte Carlo calculated potential energy curve for the helium dimer

We report on the results of both the diffusion quantum Monte Carlo (DMC) and reptation quantum Monte Carlo (RMC) methods on the potential energy curve of the helium dimer. We show that it is possible to obtain a highly accurate description of the helium dimer. An improved stochastic reconfiguration technique is employed to optimize the many-body wave function, which is the starting point for highly accurate simulations based on the DMC and RMC methods. We find that the results of these methods are in excellent agreement with the best theoretical results at short range, especially the recently developed RMC method, yield particularly accurate results with reduced statistical error, which gives very excellent agreement across the whole potential curve. For the equilibrium internuclear distance of 5.6 bohrs, the calculated total energy with RMC method is -5.807 483 599+/-0.000 000 016 hartree and the corresponding well depth is -11.003+/-0.005 K.

THE FRIEDMANN EQUATIONS IN DEFORMED HOŘAVA–LIFSHITZ GRAVITY AND DEBYE MODEL

Considering the results from Hořava–Lifshitz (HL) theory, a more precise relation between the number of bits and area in the holographic system is proposed. With this corrected relation and Debye model, two modified Friedmann equations are derived from the Hawking temperature and the Unruh temperature separately in entropic force. These equations could be better in describing the whole evolution of the Universe.

The Klein-Gordon Equation in Machian Model

The non-local Machian model is regarded as an alternative theory of gravitation which states that all particles in the Universe as a ‘gravitationally entangled’ statistical ensemble. It is shown that the Klein-Gordon equation can be derived within this Machian model of the universe. The crucial point of the derivation is the activity of the Machian energy background field which causing a fluctuation about the average momentum of a particle, the non-locality problem in quantum theory is addressed in this framework.

DENSITY FUNCTIONAL THEORY INVESTIGATE OF THE RgFn(Rg = Kr,Xe; n = 2,4,6) MOLECULES

We present a systematic Density Functional Theory (DFT) calculations for the RgFn(Rg = Kr,Xe; n = 2,4,6) molecules. The dissociation energies, harmonic vibrational frequencies and equilibrium bond lengths of these molecules are determined using several hybrid density functional methods. Results are compared with other theoretical studies and experimental values available. The accuracy of the DFT results is found to depend upon the functionals employed.