The acceleration of the expansion of the Universe which has been identified in recent years has deep connections with some of the most central issues in fundamental physics. At present, the most plausible explanation is some form of vacuum energy. The puzzle of vacuum energy is a central question which lies at the interface between quantum theory and general relativity. Solving it will presumably require to construct a quantum theory of gravity and a correspondingly consistent picture of spacetime. To account for the acceleration of the expansion, one may also think of more dynamical forms of energy, what is known as dark energy, or modifications of gravity. In what follows, we review the vacuum energy problem as well as the basic models for dark energy or modification of gravity. We emphasize the conceptual aspects rather than the techniques involved. We also discuss the difficulties encountered in each approach. This review is intended for astrophysicists or physicists not specialized in particle physics, who are interested in apprehending the issues at stake in fundamental physics.

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暗能量与基础物理学

近年来发现的宇宙膨胀加速与基础物理学中的一些最核心问题有着深刻的联系。目前，最合理的解释是某种形式的真空能。真空能量之谜是一个核心问题，它位于量子理论和广义相对论的交界处。解决它可能需要构建一个量子引力理论和一个相应一致的时空图。为了解释膨胀的加速，人们还可以想到更多动态形式的能量，即所谓的暗能量，或重力的变化。在下文中，我们将回顾真空能量问题以及暗能量或重力修正的基本模型。我们强调概念方面而不是所涉及的技术。我们还讨论了每种方法中遇到的困难。这篇综述是为天体物理学家或非粒子物理学专业的物理学家准备的，他们有兴趣理解基础物理学中的关键问题。