Charge Fluctuations in the Two-Dimensional One-Component Plasma
Charge Fluctuations in the Two-Dimensional One-Component Plasma
复制标题
二维单组分等离子体中的电荷涨落
DOI：
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复制
发表时间：
1999
期刊：
影响因子：
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通讯作者：
J. Lebowitz
中科院分区：
文献类型：
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作者：
D. Levesque;J. Weis;J. Lebowitz
通过计算机模拟，我们研究了在一个更大的中性系统中，在一个区域Λ内具有均匀背景电荷密度−eρ的二维单组分等离子体（OCP）中净电荷的涨落。设e=1，这与NΛ的波动相同，N Λ是电荷为e的移动的粒子的数量。正如预期的那样，对于大的Λ，NΛ的分布具有高斯形式，其方差仅随^κ增长。|∂Λ|得双曲余切值.| ∂Λ|是Λ的周长。该系统的性质仅取决于耦合参数Γ=kT，这与我们单位中的温度倒数相同。我们的模拟表明，当耦合参数Γ增加时，^κ（Γ）减小到渐近值^κ（∞）<$^κ（2）/2，该渐近值等于（或非常接近）刚性三角形晶格上粒子的相应方差。因此，对于大的Γ，与电荷涨落相关的特征长度<$L=2^κ/ρ的行为与德拜长度<$D <$1/
$$\sqrt \Gamma $$
，其接近为Γ→0。研究了OCP的对相关函数。
AbstractWe study, via computer simulations, the fluctuations in the net electric charge in a two-dimensional, one component plasma (OCP) with uniform background charge density −eρ in a region Λ inside a much larger overall neutral system. Setting e=1, this is the same as the fluctuations in NΛ, the number of mobile particles of charge e. As expected, the distribution of NΛ has, for large Λ, a Gaussian form with a variance which grows only as ^κ|∂Λ|, where |∂Λ| is the length of the perimeter of Λ. The properties of this system depend only on the coupling parameter Γ=kT, which is the same as the reciprocal temperature in our units. Our simulations show that when the coupling parameter Γ increases, ^κ(Γ) decreases to an asymptotic value ^κ(∞)∼^κ(2)/2 which is equal (or very close) to that obtained for the corresponding variance of particles on a rigid triangular lattice. Thus, for large Γ, the characteristic length ξL=2^κ/ρ associated with charge fluctuations behaves very differently from that of the Debye length, ξD∼1/
$$\sqrt \Gamma $$
, which it approaches as Γ→0. The pair correlation function of the OCP is also studied.