论文标题
最小耦合标量场作为不完美的流体
Minimally coupled scalar fields as imperfect fluids
论文作者
论文摘要
我们重新审视了最小耦合标量场的流体描述问题。尽管在宇宙学设置中,随着时间不断发展的标量场的解释是完善的,但是当标量场是静态的,但具有空间梯度,这种情况更加复杂,但存在空间梯度,这种情况是由标量态度理论中的黑洞扰动动机动机。然后,标量场被解释为I型特定不完美的流体,或者是一对剩下的(传入)和右转(向右的(向外)的无效粉尘的叠加,并具有完美的液体。最后,当标量梯度为无效时,它等效于II型的不完美流体,当施加能量条件时,将其退化为无效的灰尘。我们还根据每种情况的流体压力成分提出了合适的作用,并讨论了一类最小耦合标量场的变异原理。
We revisit the issue of the fluid description of minimally coupled scalar fields. While in a cosmological setup the interpretation of a time-evolving scalar field as a perfect fluid is well-understood, the situation is more intricate when the scalar field is static, but has a spatial gradient, a situation motivated by black hole perturbations in scalar-tensor theories. Then the scalar field is interpreted as either a particular imperfect fluid of type I or a superposition of a pair of leftgoing (incoming) and rightgoing (outgoing) null dusts with a perfect fluid. Finally, when the scalar gradient is null, it is equivalent to an imperfect fluid of type II, degenerating into null dust when the energy conditions are imposed. We also propose the suitable action in terms of the fluid pressure components for each case and discuss the variational principle for a generic class of minimally coupled scalar fields.