走近量子纠缠系列之四 帮倒忙的贝尔

<正>上一讲中提到的约翰·惠勒(John Wheeler,图1)是"黑洞"一词的命名者。学物理的也许记得他和他两个学生合写的那部大块头著作《引力论》(Gravitation)。此书洋洋洒洒1279页,拿起来像块大砖头,是一部既学术严谨又风格诙谐的巨著。惠勒不仅构想了"延迟选择实验",也是提出验证光子纠缠态实验的第一人。他在1948年提出,由正负电子对湮灭生成的一对散射光子应该具有两个不同的自旋,即如果     

走近量子纠缠系列之三:量子纠缠态

<正>玻尔和爱因斯坦的第三次争论,本来应该发生在1933年的第七届索尔维会议上。但是,爱因斯坦未能出席这次会议,他被纳粹赶出了欧洲,刚刚风尘仆仆地到达美国,被聘为普林斯顿高等研究院教授。德布罗意和薛定谔出席了会议,但薛定谔没见到爱因斯坦暂时不想发言,德布罗意也不想单独与人辩论。这令玻尔大大松了一口气,会议上哥本哈根派唱独角戏,看起来量子论已经根基牢靠,论战似乎尘埃落定。然而,爱因斯坦毕竟是个伟人,不是那么容易服输的。尽管他当时因战争而流离失所,未能参加     

几何画板走进分形几何

<正>我们知道分形几何是研究不规则图形和现象的一门新兴的数学分支,也是描述复杂形态的一种新的几何语言.它的重要理论和巨大价值在很多学科领域中得到了具体的体现,应用也越来越广泛.美国物理学家约翰·惠勒(J.A.Wheeler)说:"在将来,一个人如果不熟悉分形,他就不能被     

Stability problem in Rindler spacetime

The stability problem of the Rindler spacetime is carefully studies by using the scalar wave perturbation. Using two different coordinate systems, the scalar wave equation is investigated. The results are different in the two cases. They are analysed and compared with each other in detail. The following conclusions are obtained: (a) the Rindler spacetime as a whole is not stable; (b) the Rindler spacetime can exist stably only as part of the Minkowski spacetime, and the Minkowski spacetime can be a real entity independently; (c) there are some defects for the scalar wave equation written by the Rindler coordinates, and it is unsuitable for the investigation of the stability properties of the Rindler spacetime. All these results may shed some light on the stability properties of the Schwarzschild black hole. It is natural and reasonable for one to infer that: (a) perhaps the Regge--Wheeler equation is not sufficient to determine the stable properties; (b) the Schwarzschild black hole as a whole might be really unstable; (c) the Kruskal spacetime is stable and can exist as a real physical entity; whereas the Schwarzschild black hole can occur only as part of the Kruskal spacetime.