Noh Jae Dong, Park Hyunggyu
Department of Physics, Chungnam National University, Daejon 305-764, Korea.
Phys Rev E Stat Nonlin Soft Matter Phys. 2004 Jan;69(1 Pt 2):016122. doi: 10.1103/PhysRevE.69.016122. Epub 2004 Jan 30.
The well-established universality classes of absorbing critical phenomena are directed percolation (DP) and directed Ising (DI) classes. Recently, the pair contact process with diffusion (PCPD) has been investigated extensively and claimed to exhibit a different type of critical phenomenon distinct from both DP and DI classes. Noticing that the PCPD possesses a long-term memory effect, we introduce a generalized version of the PCPD (GPCPD) with a parameter controlling the memory strength. The GPCPD connects the DP fixed point to the PCPD point continuously. Monte Carlo simulations strongly suggest that the GPCPD displays, to our knowledge, novel critical phenomena which are characterized by continuously varying critical exponents. The same critical behaviors are also observed in models where two species of particles are coupled cyclically. We present one possible scenario that the long-term memory may serve as a marginal perturbation to the ordinary DP fixed point.
已确立的吸收临界现象的普适类是定向渗流（DP）类和定向伊辛（DI）类。最近，具有扩散的成对接触过程（PCPD）受到了广泛研究，并声称展现出一种与DP类和DI类都不同的临界现象类型。注意到PCPD具有长期记忆效应，我们引入了具有控制记忆强度参数的广义PCPD（GPCPD）。GPCPD将DP不动点与PCPD点连续连接起来。蒙特卡罗模拟有力地表明，据我们所知，GPCPD展示出以连续变化的临界指数为特征的新型临界现象。在两种粒子循环耦合的模型中也观察到了相同的临界行为。我们提出一种可能的情形，即长期记忆可能作为对普通DP不动点的一种边缘微扰。
