Editing Leo Szilard (section)

=== Time in Berlin ===
Convinced that there was no future for him in Hungary, Szilard left for [[Berlin]] via Austria on December 25, 1919, and enrolled at the [[Technische Universität Berlin|Technische Hochschule (Institute of Technology) in Berlin-Charlottenburg]]. He was soon joined by his brother Béla.{{sfn|Lanouette|Silard|1992|pp=49–52}} Szilard became bored with engineering, and his attention turned to [[physics]]. This was not taught at the Technische Hochschule, so he transferred to [[Humboldt University of Berlin|Friedrich Wilhelm University]], where he attended lectures given by [[Albert Einstein]], [[Max Planck]], [[Walter Nernst]], [[James Franck]] and [[Max von Laue]].{{sfn|Lanouette|Silard|1992|pp=56–58}} He also met fellow Hungarian students [[Eugene Wigner]], [[John von Neumann]] and [[Dennis Gabor]].{{sfn|Hargittai|2006|p=44}}

Szilard's doctoral [[dissertation]] on [[thermodynamics]] ''Über die thermodynamischen Schwankungserscheinungen'' (On The Manifestation of Thermodynamic Fluctuations), praised by Einstein, won top honors in 1922. It involved a long-standing puzzle in the [[philosophy of thermal and statistical physics]] known as [[Maxwell's demon]], a [[thought experiment]] originated by the [[physicist]] [[James Clerk Maxwell]]. The problem was thought to be insoluble, but in tackling it Szilard recognized the connection between thermodynamics and [[information theory]].<ref>{{cite journal |journal=Zeitschrift für Physik |title=Über die Ausdehnung der phänomenologischen Thermodynamik auf die Schwankungserscheinungen |language=de |volume=32 |issue=1 |pages=753–788 |date=December 1, 1925 |doi=10.1007/BF01331713 |issn=0044-3328 |first=Leo |last=Szilard |bibcode = 1925ZPhy...32..753S |s2cid=121162622 }}</ref>{{sfn|Lanouette|Silard|1992|pp=60–61}}
Szilard was appointed as assistant to von Laue at the Institute for Theoretical Physics in 1924. In 1927 he finished his [[habilitation]] and became a ''[[Privatdozent]]'' (private lecturer) in physics. For his habilitation lecture, he produced a second paper on Maxwell's demon, ''Über die Entropieverminderung in einem thermodynamischen System bei Eingriffen intelligenter Wesen'' (On the reduction of entropy in a thermodynamic system by the intervention of intelligent beings), that had actually been written soon after the first. This introduced the thought experiment now called the [[Szilard engine]] and became important in the history of attempts to understand Maxwell's demon. The paper also introduced the first equation linking negative entropy and information. This work established Szilard as a foundational figure in information theory; however, he did not publish it until 1929 and chose not to pursue the topic further.<ref>{{Cite journal|first=Leo |last=Szilard |year=1929 |title=Über die Entropieverminderung in einem thermodynamischen System bei Eingriffen intelligenter Wesen |language=de |journal=Zeitschrift für Physik |volume=53 |issue=11–12 |pages=840–856 |doi=10.1007/BF01341281 |issn=0044-3328 |bibcode=1929ZPhy...53..840S |s2cid=122038206 }} Available on-line in English at [http://aurellem.org/jaynes/sources/Szilard.pdf Aurellen.org].</ref>{{sfn|Lanouette|Silard|1992|pp=62–65}} [[Cybernetics]], via the work of [[Norbert Wiener]] and [[Claude E. Shannon]], would later develop the concept into a general theory in the 1940s and 1950s—though, during the time of the [[Macy conferences|Cybernetics Meetings]], [[John Von Neumann]] pointed out that Szilard first equated information with entropy in his review of Wiener's [[Cybernetics: Or Control and Communication in the Animal and the Machine|Cybernetics book]].<ref>{{Cite journal|first=John |last=von Neumann |year=1949 |title=Review of Norbert Wiener, cybernetics |journal=Physics Today |volume=2 |pages=33–34}}</ref><ref>{{Cite book|first=Ronald |last=Kline |year=2015 |title=The cybernetics moment: Or why we call our age the information age |publisher=JHU Press}}</ref>

Throughout his time in Berlin, Szilard worked on numerous technical inventions. In 1928 he submitted a [[patent]] application for the [[linear accelerator]], not knowing of [[Gustav Ising]]'s prior 1924 journal article and [[Rolf Widerøe]]'s operational device,<ref>{{Cite journal | last1 = Telegdi | first1 = V. L. | title = Szilard as Inventor: Accelerators and More | doi = 10.1063/1.1325189 | journal = Physics Today | volume = 53 | issue = 10 | pages = 25–28 | year = 2000 |bibcode = 2000PhT....53j..25T | doi-access = free }}</ref>{{sfn|Calaprice|Lipscombe|2005|p=110}} and in 1929 applied for one for the [[cyclotron]].{{sfn|Lanouette|Silard|1992|pp=101–102}} He was also the first person to conceive the idea of the [[electron microscope]],{{sfn|Lanouette|Silard|1992|pp=83–85}} and submitted the earliest patent for one in 1928.<ref name="budtalk" /> Between 1926 and 1930, he worked with Einstein to develop the [[Einstein refrigerator]], notable because it had no moving parts.<ref>{{US patent|1781541}}</ref> He did not build all of these devices, or publish these ideas in [[scientific journals]], and so credit for them often went to others. As a result, Szilard never received the [[Nobel Prize]], but [[Ernest Lawrence]] was awarded it for the cyclotron in 1939, and [[Ernst Ruska]] for the electron microscope in 1986.<ref name="budtalk">{{cite web |first=Gene |last=Dannen |title=Leo Szilard the Inventor: A Slideshow |date=February 9, 1998 |url=http://www.dannen.com/budatalk.html |access-date=May 24, 2015 }}</ref>

[[File:Fermi-Szilard Neutronic Reactor - Figure 38.png|right|upright|thumb|An image from the Fermi–Szilard "neutronic reactor" patent]]
Szilard received German citizenship in 1930, but was already uneasy about the political situation in Europe.{{sfn|Fraser|2012|p=71}} When [[Adolf Hitler]] became [[chancellor of Germany]] [[Machtergreifung|on January 30, 1933]], Szilard urged his family and friends to flee Europe while they still could.{{sfn|Lanouette|Silard|1992|pp=62–65}} He moved to England, and transferred his savings of £1,595 (£{{Inflation|UK|1595|1933|r=-2|fmt=c}} today) from his bank in [[Zürich]] to one in [[London]]. He lived in hotels where lodging and meals cost about £5.5 a week.{{sfn|Rhodes|1986|p=26}} For those less fortunate, he helped found the [[Council for Assisting Refugee Academics|Academic Assistance Council]], an organization dedicated to helping refugee scholars find new jobs, and persuaded the [[Royal Society]] to provide accommodation for it at [[Burlington House]]. He enlisted the help of academics such as [[Harald Bohr]], [[G. H. Hardy]], [[Archibald Hill]] and [[Frederick G. Donnan]]. By the outbreak of World War II in 1939, it had helped to find places for over 2,500 refugee scholars.{{sfn|Lanouette|Silard|1992|pp=119–122}}