# 普朗克常数

（重定向自狄拉克常數

${\displaystyle E=h\nu }$

 ${\displaystyle h}$ ${\displaystyle =6.626069934(89)\times 10^{-34}}$J⋅s.[1] ${\displaystyle =4.135667662(25)\times 10^{-15}}$eV⋅s[2]

## 約化普朗克常數

${\displaystyle \hbar \equiv {\frac {h}{2\pi }}=1.054\ 571\ 800(13)\times 10^{-34}\ {\mbox{J}}\cdot {\mbox{s}},}$

${\displaystyle E=nh\nu \,,\quad n\in \mathbb {N} }$

${\displaystyle E=n\hbar \omega \,,\quad n\in \mathbb {N} }$

${\displaystyle {\begin{matrix}J^{2}=j(j+1)\hbar ^{2},&j=0,1/2,1,3/2,\ldots \\J_{z}=m\hbar ,\qquad \quad &m=-j,-j+1,\ldots ,j\end{matrix}}}$

${\displaystyle \Delta x\Delta p\geq {\begin{matrix}{\frac {1}{2}}\end{matrix}}\hbar }$

1919年，阿諾·索末菲在他的《原子构造和光谱线》一书中最早将1900年12月14日称为“量子理论的诞辰”，后来的科学史家们将这一天定为了量子的诞生日。

## 参考文献

1. ^ Schlamminger, S.; Haddad, D.; Seifert, F.; Chao, L. S.; Newell, D. B.; Liu, R.; Steiner, R. L.; Pratt, J. R. Determination of the Planck constant using a watt balance with a superconducting magnet system at the National Institute of Standards and Technology. Metrologia. 2014, 51 (2): S15. ISSN 0026-1394. doi:10.1088/0026-1394/51/2/S15 （英语）.
2. ^ Barry N. Taylor of the Data Center in close collaboration with Peter J. Mohr of the Physical Measurement Laboratory's Atomic Physics Division, Termed the "2014 CODATA recommended values," they are generally recognized worldwide for use in all fields of science and technology. The values became available on 25 June 2015 and replaced the 2010 CODATA set. They are based on all of the data available through 31 December 2014. Available: http://physics.nist.gov页面存档备份，存于互联网档案馆
3. ^ Ghosh, Pallab. Kilogram gets a new definition. BBC News. 2018-11-16 [2018-11-16]. （原始内容存档于2018-11-16） （英国英语）.
4. ^ Planck constant. 美國國家標準和技術研究院. [2022-06-07]. （原始内容存档于2022-05-27） （英语）.