Condensation of classical nonlinear waves
Condensation of classical nonlinear waves
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DOI：
10.1103/physrevlett.95.263901
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发表时间：
2005-12-31
影响因子：
8.6
通讯作者：
Rica, S
中科院分区：
文献类型：
--
作者：
Connaughton, C;Josserand, C;Rica, S
我们以散焦非线性薛定谔方程为代表模型，研究经典波动方程中大尺度相干结构（凝聚体）的形成。我们利用具有紫外线截止功能的波湍流理论对经典凝结过程进行了热力学描述。在三维中，平衡态经历相变以获得足够低的能量密度，而在二维中不发生相变，这与量子系统中的标准玻色-爱因斯坦凝聚完全类似。基于修正的波湍流理论，我们表明非线性相互作用使得凝结亚临界转变。该理论与非线性薛定谔方程的数值积分在数量上一致。
We study the formation of a large-scale coherent structure (a condensate) in classical wave equations by considering the defocusing nonlinear Schrodinger equation as a representative model. We formulate a thermodynamic description of the classical condensation process by using a wave turbulence theory with ultraviolet cutoff. In three dimensions the equilibrium state undergoes a phase transition for sufficiently low energy density, while no transition occurs in two dimensions, in complete analogy with standard Bose-Einstein condensation in quantum systems. On the basis of a modified wave turbulence theory, we show that the nonlinear interaction makes the transition to condensation subcritical. The theory is in quantitative agreement with the numerical integration of the nonlinear Schrodinger equation.