标题： 托尔曼虫洞违反强能量条件 显示英文标题

标题： Tolman wormholes violate the strong energy condition

摘要： 对于一个任意的Tolman虫洞，不受对称性约束，我们将通过一个三维无边的类空非因果超曲面（体积最小）来定义回波。 （外曲率迹为零加上一个“扩张”条件。） 这使我们能够严格限制回波附近时空的几何结构，并推导出关于能量条件违反的一般定理——这些定理不涉及测地线平均，但仍然适用于比高度对称的FRW基Tolman虫洞子类更广泛的情况。 [例如：即使在最温和的假定下，强能量条件（SEC）也必须被违反。] 或者，可以放弃体积最小的条件，完全通过测试粒子的运动（未来指向的类时测地线）来定义一般的回波，通过观察其类时测地线流的膨胀情况。 人们再次确认，在回波处或附近必须违反SEC。 相比之下，很容易安排其他所有标准能量条件得到满足。 显示英文摘要

摘要： For an arbitrary Tolman wormhole, unconstrained by symmetry, we shall define the bounce in terms of a three-dimensional edgeless achronal spacelike hypersurface of minimal volume. (Zero trace for the extrinsic curvature plus a "flare-out" condition.) This enables us to severely constrain the geometry of spacetime at and near the bounce and to derive general theorems regarding violations of the energy conditions--theorems that do not involve geodesic averaging but nevertheless apply to situations much more general than the highly symmetric FRW-based subclass of Tolman wormholes. [For example: even under the mildest of hypotheses, the strong energy condition (SEC) must be violated.] Alternatively, one can dispense with the minimal volume condition and define a generic bounce entirely in terms of the motion of test particles (future-pointing timelike geodesics), by looking at the expansion of their timelike geodesic congruences. One re-confirms that the SEC must be violated at or near the bounce. In contrast, it is easy to arrange for all the other standard energy conditions to be satisfied.