标题： 关于膨胀宇宙中准局部能量守恒的注意 显示英文标题

标题： Note on the Conservation of Quasi-Local Energy in an Expanding Universe

摘要： 在不断膨胀的宇宙中能量是否守恒是一个引人入胜的问题。 人们很容易认为，随着宇宙的膨胀，宇宙中的总能量必须增加。 但经过更详细的检查，这个问题要解决起来要困难得多，因为在广义相对论中，定义什么是能量，甚至什么是能量守恒本身都是一个困难的问题。 我们使用布朗和约克提供的准局部能量定义，尝试回答在什么意义上，膨胀（或坍缩）宇宙中的总能量是守恒的。 显示英文摘要

摘要： Whether energy is conserved in a universe which keeps expanding is an intriguing question. It is tempting to argue that the total energy within the universe would have to increase as the universe expands. Upon more detailed inspection the question is a lot harder to settle since defining what is meant by energy or even what is meant by energy being conserved is a difficult problem in general relativity. Using the definition of quasi-local energy provided by Brown and York we try to answer the question in which sense the total energy in an expanding (or collapsing) universe is conserved.