标题： 定义熵界 显示英文标题

标题： Defining Entropy Bounds

摘要： Bekenstein提出的关于线性尺寸为R和能量为E的系统的熵界限S < 2 pi E R，对于"系统"、R、E和S的许多定义方式都有反例。 这里提出了新的方法来定义这些量，在平坦时空中的任意非引力量子场论中，例如将R定义为在该半径之外只有真空期望值出现。 指出了将这些定义扩展到引力量子理论时的困难。 显示英文摘要

摘要： Bekenstein's conjectured entropy bound for a system of linear size R and energy E, S < 2 pi E R, has counterexamples for many of the ways in which the "system," R, E, and S may be defined. Here new ways are proposed to define these quantities for arbitrary nongravitational quantum field theories in flat spacetime, such as defining R as the smallest radius outside of which only vacuum expectation values occur. Difficulties of extending these definitions to gravitational quantum theories are noted.