Adiabatic and entropy perturbations with interacting fluids and fields
Adiabatic and entropy perturbations with interacting fluids and fields
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DOI：
10.1088/1475-7516/2005/02/007
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发表时间：
2004-11
影响因子：
6.4
通讯作者：
Karim A. Malik;D. Wands
中科院分区：
文献类型：
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作者：
Karim A. Malik;D. Wands
我们发展了一个规范不变的形式来研究具有多个相互作用的流体和/或标量场的Friedmann-Robertson-Walker宇宙中的密度微扰。我们展示了N个动力学流体(具有最大刚性状态方程)如何与非动力学势(具有真空状态方程)相互作用来描述N个标量场。我们将一般摄动分解为绝热部分和熵部分，并给出了包括能量和动量交换在内的所有尺度上的耦合一阶演化方程。我们确定了大尺度上的非绝热效应，并定义了多流体和多场存在时的绝热初始条件。
We develop a gauge-invariant formalism for the study of density perturbations in a Friedmann–Robertson–Walker universe with multiple interacting fluids and/or scalar fields. We show how N scalar fields may be described by N kinetic fluids (with maximally stiff equation of state) interacting with a non-dynamical potential (with vacuum equation of state). We split generic perturbations into adiabatic and entropic parts, and give the coupled first-order evolution equations on all scales, including energy and momentum exchange. We identify the non-adiabatic effects on large scales, and define adiabatic initial conditions in the presence of multiple fluids and fields.