标题： 形成无序手征凝聚体通过波动 显示英文标题

标题： Forming Disoriented Chiral Condensates through Fluctuations

摘要： 利用影响泛函形式主义，在存在热浴的情况下，推导出了O(N)模型的经典运动方程，既适用于对称相，也适用于自发对称破缺相。 热浴导致经典运动方程中出现耗散项和涨落项，这些项在微扰论的最低阶被明确计算出来。 在破缺相中，由于sigma到pi pi的衰变过程，即使在零温下，这些项对于sigma场来说很大，而对于pi场来说，在温度低于T_c = 160 MeV时则很小。 研究表明，在大体积情况下，耗散和涨落的存在抑制了不对称手征凝聚态（DCC）的形成。 然而，在小体积情况下，涨落变得足够大，即使手征对称性在系统演化的初始阶段没有恢复，也能诱导DCC的形成。 显示英文摘要

摘要： Using the influence functional formalism, classical equations of motion for the O(N) model are derived in the presence of a heat bath, in both the symmetric phase as well as the phase of spontaneously broken symmetry. The heat bath leads to dissipation and fluctuation terms in the classical equations of motion, which are explicitly computed to lowest order in perturbation theory. In the broken phase these terms are found to be large for the sigma field, even at zero temperature, due to the decay process sigma -> pi pi, while they are small for the pi fields at temperatures below T_c = 160 MeV. It is shown that in large volumes the presence of dissipation and fluctuations suppresses the formation of disoriented chiral condensates (DCC's). In small volumes, however, fluctuations become sufficiently large to induce the formation of DCC's even if chiral symmetry has not been restored in the initial stage of the system's evolution.