Exact Conservation Laws of the Gradient Expanded Kadanoff–Baym Equations
Exact Conservation Laws of the Gradient Expanded Kadanoff–Baym Equations
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DOI：
10.1006/aphy.2001.6185
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发表时间：
2001-02
影响因子：
3
通讯作者：
J. Knoll;Y. Ivanov;D. Voskresensky
中科院分区：
文献类型：
--
作者：
J. Knoll;Y. Ivanov;D. Voskresensky
摘要 结果表明，一致一阶梯度近似下的 Kadanoff-Baym 方程揭示了与系统全局对称性相关的精确守恒定律，而不是近似守恒定律。守恒电流和能量动量张量与局部近似中相应的诺特量一致。这些精确的守恒是有效的，只要使用 Φ 可导近似来描述系统，并且碰撞项中可能的记忆效应也一致地评估到一阶梯度。
Abstract It is shown that the Kadanoff-Baym equations at consistent first-order gradient approximation reveal exact rather than approximate conservation laws related to global symmetries of the system. The conserved currents and energy–momentum tensor coincide with corresponding Noether quantities in the local approximation. These exact conservations are valid, provided a Φ derivable approximation is used to describe the system, and possible memory effects in the collision term are also consistently evaluated up to first-order gradients.