Satyendra Nath Bose (1894-1974) from India is remembered for co-introducing the state of matter known as a Bose-Einstein condensate (BEC), where atoms or subatomic particles, cooled to near absolute zero (0 K, or minus 273.15 °C), coalesce into a single quantum mechanical entity. The process is similar to condensation when drops of liquid form from a gas. This state of matter was predicted in 1924 by Einstein on the basis of Bose’s quantum formulations. His name is honored in the name of a class of particles called “bosons.” The particle class known as “fermions” is named after the Italian nuclear physicist Enrico Fermi.- - - - - - - - -
Eric Cornell (born 1961) and Carl Wieman (born 1951) from the USA shared the Nobel Prize in Physics in 2001 with the German scientist Wolfgang Ketterle (born 1957) for the first successful creation of a Bose-Einstein condensate in 1995. What happens is that “when a given number of identical Bose particles approach each other sufficiently closely, and move sufficiently slowly, they will collectively convert to the lowest energy state: a BEC. This occurs when atoms are chilled to very low temperatures. The wavelike nature of atoms allows them to spread out and even overlap. If the density is high enough, and the temperature low enough (mere billionths of degrees above absolute zero), the atoms will behave like the photons in a laser: they will be in a coherent state and constitute a single ‘super atom.’“
BECs are related to superconductivity, a phenomenon of virtually zero electrical resistance which occurs in certain materials at very low temperatures. Superconductivity and superfluidity are cases of macroscopic quantum phenomena, quantum behavior observable on the human scale. Because of the European electrochemical revolution, the nineteenth and twentieth centuries saw rapid advances in the production of low temperatures, or cryogenics.
The Dutch physicist Heike Kamerlingh Onnes (1853-1926), following advances made by fellow Dutchman Johannes Diderik van der Waals, managed to liquify helium. Johannes Diderik van der Waals (1837-1923) was born in the famous university town of Leiden in the Netherlands, where he also studied, before he in 1876 was appointed the first Professor of Physics at the newly established University of Amsterdam. “Together with Van’t Hoff and Hugo de Vries, the geneticist, he contributed to the fame of the University, and remained faithful to it until his retirement, in spite of enticing invitations from elsewhere.” He made extremely valuable contributions to the study of gases and liquids and was awarded the Nobel Prize in Physics in 1910 for his groundbreaking research on these states of matter. He also served as a guide for the experiments which led to the liquefaction of hydrogen and helium.
The brilliant Dutch physical chemist Jacobus Henricus van ‘t Hoff (1852-1911) was born in Rotterdam, the son of a physician, and studied at the Polytechnic School at Delft. He then proceeded to Bonn to work with the great German organic chemist Friedrich Kekulé. In 1878 he was appointed Professor of Chemistry, Mineralogy and Geology at the University of Amsterdam. His pressure laws, given general validity by the electrolytic dissociation theory of Svante Arrhenius from Sweden (1884-1887), are considered the most comprehensive in the realm of natural sciences. He accepted an invitation to go to Berlin from 1896 to 1905.
Wilhelm Ostwald (1853-1932) was a Baltic German born in Riga, Latvia, graduated from the University of Tartu, Estonia. In 1881 he became Professor of Chemistry at the Polytechnicum in Riga. Six years later he was appointed Professor of Physical Chemistry at Leipzig University. Walther Nernst (1864-1941) was born in West Prussia (now Poland) and went to the Universities of Zürich, Berlin and Graz where he studied physics and mathematics. In 1887 he became an assistant to Ostwald at Leipzig University in Germany, where van’t Hoff and Arrhenius were already established. All four of these men won well-deserved Nobel Prizes in Chemistry and are considered co-founders of physical chemistry. According to the Third Law of Thermodynamics, formulated by Walther Nernst in 1905, absolute zero cannot be attained by any means, but scientists have attained temperatures of a tiny fraction above it.
Nobel laureate Heike Kamerlingh Onnes was born at Groningen in the Netherlands. In 1870 he entered the University of Groningen and went on to Heidelberg, Germany as a student of Bunsen and Kirchhoff. He devoted his career to a quest to explore the behavior of matter at extremely low temperatures. Raoul Pictet (1846-1929) from Switzerland and Louis-Paul Cailletet (1832-1913) from France independently liquefied small amounts of oxygen in 1877.
In 1898 the Scottish scientist James Dewar (1842-1923), also remembered for his invention of the vacuum flask known as the thermos with its valuable heat-preserving properties, beat him in the race to liquefy hydrogen. Onnes moved on to liquefying helium in 1908, which made it possible to cool other substances, too, and study the properties of matter near absolute zero. His Dutch student Willem Hendrik Keesom (1876-1956) managed to solidify helium in 1926.
In 1911 he began studying the electrical conductivity of metals at low temperatures. “Keeping the mercury in a U-shaped tube with wires at both ends, he passed a current through it and measured resistance as he lowered the temperature. At first, as the temperature dropped, the resistance also dropped slowly. Then, suddenly, at 4.19 Kelvin, the resistance abruptly vanished.” This result had not been predicted by anyone. His team repeated the experiment until they were convinced that the effect was real. Onnes coined the term superconductivity and showed that tin and lead, too, become superconducting at very low temperatures.
The Russian physicist Pyotr Kapitsa (1894-1984) studied in Russia and went to Cambridge University in Britain to work with Ernest Rutherford. Nobody expected him to return to the Soviet Union at the time of Joseph Stalin’s ruthless Communist regime, but while visiting friends in 1934 the police detained him. Soviet authorities gave him a laboratory in Moscow. He eventually accepted his fate, but retained a remarkable independence of spirit. In 1937, Kapitsa found that liquefied helium flows with almost no internal friction, displaying bizarre behavior such as a tendency to climb spontaneously out of its container. This is called superfluidity. He got the 1978 Nobel Prize in Physics for his work in low temperature physics.
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