Editing Johnson–Nyquist noise (section)

== History of thermal noise ==
In 1905, in one of [[Albert Einstein]]'s [[Annus mirabilis papers|''Annus mirabilis'' papers]] the theory of [[Brownian motion]] was first solved in terms of thermal fluctuations. The following year, in a second paper about Brownian motion, Einstein suggested that the same phenomena could be applied to derive thermally-agitated currents, but did not carry out the calculation as he considered it to be untestable.<ref name=":0">{{Cite journal |last=Dörfel |first=G. |date=2012-08-15 |title=The early history of thermal noise: The long way to paradigm change |url=https://onlinelibrary.wiley.com/doi/10.1002/andp.201200736 |journal=Annalen der Physik |language=en |volume=524 |issue=8 |pages=117–121 |doi=10.1002/andp.201200736 |issn=0003-3804}}</ref>

[[Geertruida de Haas-Lorentz]], daughter of [[Hendrik Lorentz]], in her doctoral thesis of 1912, expanded on Einstein stochastic theory and first applied it to the study of electrons, deriving a formula for the mean-squared value of the thermal current.<ref name=":0" /><ref>{{Citation |last=Van Der Ziel |first=A. |title=Advances in Electronics and Electron Physics Volume 50 |chapter=History of Noise Research |date=1980-01-01 |volume=50 |pages=351–409 |editor-last=Marton |editor-first=L. |chapter-url=https://www.sciencedirect.com/science/article/pii/S0065253908610665 |access-date=2024-03-16 |publisher=Academic Press |doi=10.1016/s0065-2539(08)61066-5 |isbn=978-0-12-014650-5 |editor2-last=Marton |editor2-first=C.}}</ref>

[[Walter H. Schottky]] studied the problem in 1918, while studying thermal noise using Einstein's theories, experimentally discovered another kind of noise, the [[shot noise]].<ref name=":0" />

[[Frits Zernike]] working in electrical metrology, found unusual random deflections while working with high-sensitive [[Galvanometer|galvanometers]]. He rejected the idea that the noise was mechanical, and concluded that it was of thermal nature. In 1927, he introduced the idea of autocorrelations to electrical measurements and calculated the time detection limit. His work coincided with De Haas-Lorentz' prediction.<ref name=":0" />

The same year, working independently without any knowledge of Zernike's work, [[John Bertrand Johnson|John B. Johnson]] working in [[Bell Labs]] found the same kind of noise in communication systems, but described it in terms of frequencies.<ref>{{Cite journal |doi = 10.1103/PhysRev.29.350|title = Minutes of the Philadelphia Meeting December 28, 29, 30, 1926|journal = Physical Review|volume = 29|issue = 2|pages = 350–373|year = 1927|last1 = Anonymous|bibcode = 1927PhRv...29..350.}}</ref><ref name=":2">{{cite journal|first=J.|last=Johnson|title=Thermal Agitation of Electricity in Conductors|journal= Physical Review|volume=32|pages=97–109|number=97|date=1928|doi=10.1103/physrev.32.97|bibcode=1928PhRv...32...97J}}</ref><ref name=":0" /> He described his findings to [[Harry Nyquist]], also at Bell Labs, who used principles of [[thermodynamics]] and [[statistical mechanics]] to explain the results, published in 1928.<ref name="Nyquist">{{cite journal|first=H.|last=Nyquist|title=Thermal Agitation of Electric Charge in Conductors|journal= Physical Review|volume=32|pages=110–113|number=110|date=1928|doi=10.1103/physrev.32.110|bibcode=1928PhRv...32..110N}}</ref>