# GetWiki

### phase factor

ARTICLE SUBJECTS
news  →
unix  →
wiki  →
ARTICLE TYPES
feed  →
help  →
wiki  →
ARTICLE ORIGINS phase factor
[ temporary import ]
- the content below is remote from Wikipedia
- it has been imported raw for GetWiki
{{Refimprove|date=December 2009}}For any complex number written in polar form (such as reiÎ¸), the phase factor is the complex exponential factor (eiÎ¸). As such, the term "phase factor" is related to the more general term phasor, which may have any magnitude (i.e., not necessarily part of the circle group). The phase factor is a unit complex number, i.e., of absolute value 1. It is commonly used in quantum mechanics. The variable Î¸ appearing in such an expression is generally referred to as the phase. Multiplying the equation of a plane wave Aei(kÂ·râˆ’Ï‰t) by a phase factor shifts the phase of the wave by Î¸:
text{e}^{itheta}Atext{e}^{ileft({mathbf{k}cdotmathbf{r}-omega t}right)} = Atext{e}^{ileft({mathbf{k}cdotmathbf{r}-omega t + theta}right)}.
In quantum mechanics, a phase factor is a complex coefficient eiÎ¸ that multiplies a ket |psirangle or bra langlephi|. It does not, in itself, have any physical meaning, since the introduction of a phase factor does not change the expectation values of a Hermitian operator. That is, the values of langlephi|A|phirangle and langlephi|e^{-itheta} A e^{itheta}|phirangle are the same.{{harvtxt|Messiah|1999|p=296}} However, differences in phase factors between two interacting quantum states can sometimes be measurable (such as in the Berry phase) and this can have important consequences.In optics, the phase factor is an important quantity in the treatment of interference.

{{reflist}}

## References

- content above as imported from Wikipedia
- "phase factor" does not exist on GetWiki (yet)
- time: 3:53am EST - Tue, Nov 12 2019
[ this remote article is provided by Wikipedia ]
LATEST EDITS [ see all ]
GETWIKI 09 JUL 2019
Eastern Philosophy
History of Philosophy
GETWIKI 09 MAY 2016
GETWIKI 18 OCT 2015
M.R.M. Parrott
Biographies
GETWIKI 20 AUG 2014
GETWIKI 19 AUG 2014