arXiv subjects

Peng Zhang

Publications and source records attributed to Peng Zhang.

872 records · Page 49Linked to original sources

arXiv2005

Simulation Study of Internal and Surface waves of Vertically Vibrated Granular Materials

Molecular dynamical (MD) simulations are performed to simulate two dimensional vibrofluidized granular materials in this work. Statistics on simulation results indicate that there exist shocks propagating upward in each vibrating cycle. Under certain driving parameters surface waves similar to Faraday instability in normal fluid coexist with internal waves. Relationship between the two kinds of waves is explored. Moreover simulation results indicate that periodically structured bottom can change the dispersion relationship and amplitude of surface waves.

cond-mat.soft↗

arXiv2005

Dynamic Behaviors of Supersonic Granular Media under Vertical Vibration

We present experimental study of vibrofluidized granular materials by high speed photography. Statistical results present the averaged dynamic behaviors of granular materials in one cycle, including the variations of height, velocity and mechanical energy of the center of mass. Furthermore, time-space distribution of granular temperature which corresponds to the random kinetic energy shows that a temperature peak forms in the compression period and propagates upward with a steepened front. The Mach number in the steepened front is found to be greater than unity, indicating a shock propagating in the supersonic granular media.

cond-mat.soft↗

arXiv2005

Shock wave propagation in vibrofluidized granular materials

Shock wave formation and propagation in two-dimensional granular materials under vertical vibration are studied by digital high speed photography. The steepen density and temperature wave fronts form near the plate as granular layer collides with vibrating plate and propagate upward through the layer. The temperature front is always in the transition region between the upward and downward granular flows. The effects of driving parameters and particle number on the shock are also explored.

cond-mat.soft↗

arXiv2005

Formation and transportation of sand-heap in an inclined and vertically vibrated container

We report the experimental findings of formation and motion of heap in granular materials in an inclined and vertically vibrated container. We show experimentally how the transport velocity of heap up container is related to the driving acceleration as well as the driving frequency of exciter. An analogous experiment was performed with a heap-shaped Plexiglas block. We propose that cohesion force resulted from pressure gradient in ambient gas plays a crucial role in enhancing and maintaining a heap, and ratchet effect causes the movement of the heap. An equation which governs the transport velocity of the heap is presented.

cond-mat.soft↗

arXiv2005

The Community Structure of Econophysicist Collaboration Networks

This paper uses a database of collaboration recording between Econophysics Scientists to study the community structure of this collaboration network, which with a single type of vertex and a type of undirected, weighted edge. Hierarchical clustering and the algorithm of Girvan and Newman are presented to analyze the data. And it emphasizes the influence of the weight to results of communities by comparing the different results obtained in different weights. A function D is proposed to distinguish the difference between above results. At last the paper also gives explanation to the results and discussion about community structure.

physics.soc-ph↗

arXiv2005

Flat Currents of the Green-Schwarz Superstrings in AdS_5 x S^1 and AdS_3 x S^3 backgrounds

We construct a one-parameter family of flat currents in AdS_5 x S^1 and AdS_3 x S^3 Green-Schwarz superstrings, which would naturally lead to a hierarchy of classical conserved nonlocal charges. In the former case we rewrite the AdS_5 x S^1 string using a new Z_4-graded base of the superalgebra su(2,2|2). In both cases the existence of the Z_4 grading in the superalgebras plays a key role in the construction. As a result, we find that the flat currents, when formally written in terms of the G_0-gauge invariant lowercase 1-forms, take the same form as the one in AdS_5 x S^5 case.

hep-th↗

arXiv2005

Quantum Monte Carlo Simulations on S=1/2 antiferromagnetic-Ferromagnetic Random Alternating spin chain

The S=1/2 Heisenberg chain with bond alternation and randomness of antiferromagnetic (AFM) and ferromagnetic (FM) interactions is investigated by quantum Monte Carlo simulations of loop/cluster algorithm. Our results have shown interesting finite temperature magnetic properties of this model. The relevance of our study to the observed results of the material (CH$_3$)$_2$CHNH$_3$Cu(Cl$_x$Br$_{1-x}$)$_3$ is discussed.

cond-mat.dis-nn↗

arXiv2001

Remote state preparation in higher dimension and the parallelizable manifold $S^{n-1}$

This paper proves that the remote state preparation (RSP) scheme in real Hilbert space can only be implemented when the dimension of the space is 2,4 or 8. This fact is shown to be related to the parallelazablity of the $n$-1 dimensional sphere $S^{n-1}$. When the dimension is 4 and 8 the generalized scheme is explicitly presented. It is also shown that for a given state with components having the same norm, RSP can be generalized to arbitrary dimension case.

quant-ph↗