# 快子

## 特徵

### 質量

${\displaystyle E^{2}=p^{2}c^{2}+m^{2}c^{4}\;}$

${\displaystyle E={\frac {mc^{2}}{\sqrt {1-{\frac {v^{2}}{c^{2}}}}}}}$

v大於c的時候，因為平方根裡面的值是負數，所以分母會有虛數。由於總能量必須是实數，因此分子也必須是虛數（亦即靜止質量m必須是虛數）。

• 對質量的域做簡單的替代會導致對快子具有實際的質量。定義m = i*z（${\displaystyle i^{2}=-1}$）然後，我們會得到愛因斯坦的能量-動量關係式：
${\displaystyle E^{2}+z^{2}c^{4}=p^{2}c^{2}\;}$

${\displaystyle E={\frac {zc^{2}}{\sqrt {{\frac {v^{2}}{c^{2}}}-1}}}}$

## 對照與參考

1. ^ /ˈtæki.ɒn/，来自希腊语ταχυόνιονtakhyónion），源自ταχύςtakhýs），意為快、迅速
2. ^ Bilaniuk, Olexa-Myron P.; . Particles beyond the Light Barrier. Physics Today. May 1969, 22 (5): 43–51. doi:10.1063/1.3035574.
3. Bilaniuk, Olexa-Myron P.; Deshpande, Vijay K.; Sudarshan, E. C. George. Meta Relativity. American Journal of Physics. 1962, 30: 718ff. doi:10.1119/1.1941773.
4. Feinberg, Gerald. Possibility of Faster-Than-Light Particles. Physical Review. 1967, 159: 1089–1105. doi:10.1103/PhysRev.159.1089.
5. Peskin, Michael E.; and Schroeder, Daniel V. (1995) An Introduction to Quantum Field Theory, Perseus books publishing.
6. ^ G. A. Benford, D. L. Book, and W. A. Newcomb, "The Tachyonic Antitelephone," Physical Review, part D 2 263, DOI: 10.1103, July 15, 1970, pp. 263-265
7. ^ 存档副本. [2011-09-23]. （原始内容存档于2007-12-18）.
8. ^ Grøn, Øyvind; Sigbjørn Hervik. Einstein's General Theory of Relativity: With Modern Applications in Cosmology. Springer. 2007: 39]. ISBN 978-0387691992.
9. Jarrell, Mark. The Special Theory of Relativity (PDF): 7–11. [2006-10-27]. （原始内容 (PDF)存档于2006-09-13）.
10. ^ Chase, Scott I. Tachyons. March [2009-12-03]. （原始内容存档于2020-11-25）.
11. ^ Sen, Ashoke. 快子凝聚處於膜與反膜系統. JHEP. 1998, 08: 012. doi:10.1088/1126-6708/1998/08/012.