黑体不是黑盒
A blackbody is not a blackbox
摘要：
我们仔细讨论黑体近似，强调它是什么（辐射转移的极限情况），它不是什么（假设物体是完全吸收的，即黑色）。此外，我们推导普朗克谱，而不是像大多数教科书那样把场封闭在一个盒子里。虽然很方便，但这个技巧掩盖了黑体概念中所表达的理想化的本质：首先，近似黑体的最明显的例子，恒星，绝对不是封闭在盒子里的;其次，普朗克光谱是连续的，而盒子里的稳态辐射模式是离散的。我们的推导，虽然在技术上不太基本，是概念上更一致，并带来了机会，向学生介绍的重要概念的局部密度的状态，通过预解形式主义。
英文摘要：
We discuss carefully the blackbody approximation, stressing what it is (a limit case of radiative transfer), and what it is not (the assumption that the body is perfectly absorbing, i.e. black). Furthermore, we derive the Planck spectrum without enclosing the field in a box, as is done in most textbooks. Athough convenient, this trick conceals the nature of the idealization expressed in the concept of a blackbody: first, the most obvious examples of approximate blackbodies, stars, are definitely not enclosed in boxes; second, the Planck spectrum is continuous, while the stationary modes of radiation in a box are discrete. Our derivation, although technically less elementary, is conceptually more consistent, and brings the opportunity to introduce to students the important concept of local density of states, via the resolvent formalism.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
