ONLINE NEWSLETTER (No. 2/2005 - January 2005)

Editor: Fran Bock

One of the outstanding Soviet physicists, Leonid Mandelshtam, contributed basic concepts to the field of quantum physics. He was honored with a commemorative stamp by the Republic of Belarus in May, 2004, on the 125th anniversary of his birth.

We thank Vitaly Charny for this sketch, another in his series on noteworthy Jews from Belarus.

Reprinting or copying of this article is not allowed without prior permission from the copyrightholders.

Leonid Mandelshtam, 1879-1944

by Vitaly Charny

There are only a few scientists whose names are well known to the general public. The interpretation of their research and their discoveries is very difficult not only to judge but even to understand. It is fortunate that some of these great men appear on postage stamps among the legions of politicians and entertainers. One of them is Russian physicist Leonid I. Mandelshtam (1879-1944).

As a tribute to his memory, the Republic of Belarus postal authorities issued on May 4, 2004 a pre-stamped postal envelope with original stamp and official cachet as one of the events commemorating the 125th anniversary of his birth.

Postal stamps on the envelope depict Mandelshtam's portrait and there is an inscription in Belarusian with his name, academician rank, life and anniversary dates. On the cachet made from a photo, Mandelshtam is shown teaching oscillation theory in the Russian Academy of Science P.N.Lebedev Institute of Physics.

The special cancellation with postmark of Mogilev, Belarus post office #30, is dated May 4 , 2004. It also bears an inscription with Mandelshtam's name, life and anniversary dates and a symbolic design related to the field of his research.

Leonid Mandelshtam was one of the 20th century physicists whose monumental input into the science was greatly under estimated in terms of international public recognition. However, people familiar with his groundbreaking works and original ideas clearly recognize his undeniable preeminence in several major applications of modern physics.

Leonid Mandelshtam was borne in Mogilev, Belarus, into a well-educated Jewish family on May 5 (18), 1879 - the same year as Albert Einstein. His father, Isaac G. Mandelshtam, was famous in Southern Russia as a doctor, and his mother, M.L. Kan (Kahn) was an accomplished pianist.

The Mandelshtams of the Russian Empire trace their origin from the small Lithuanian town of Zagare (former Zhagory) on the Latvian border, where at that time Jews comprised most of the population of about 5000. From this family came some famous people in Russian culture. Leon Mandelshtam was the first Jew who enrolled in St. Petersburg University (in 1840). He became a professor and translated Torah into Russian. Other Mandelshtams advanced in science, medicine, poetry, law and other fields. Doctor Nikolai Mandelshtam, worked in Mogilev for more than 30 years until his death in 1882. He founded in 1875 and headed the Mogilev Feldsher School (kind of registered nurse school). Most likely he was from the same family. Also from the same town of Zagare came another great Jewish nuclear physicist, Isaak Kikoin, as well as the founder of the best known tea company in Imperial Russia, Kalonimus Ze'ev (Vulf) Vysotsky (Wissotzky) (1824-1904). The Wissotzky Tea Company still exists in Israel.

From the Russian census of 1858 we know that the family of Sholom Mandelshtam and his nephew Aron (who graduated from Vilno Rabbinical Seminary) moved from Zagare to Mogilev. The father of the future scientist, Isaak Grigorievich Mandelshtam, was listed among Mogilev physicians in 1867 and most probably belonged to that family.

Soon after Leonid was born, the family of Isaak Mandelshtam moved to Odessa, where in 1897 Leonid graduated from Gymnasia (classical high school) and enrolled in the Physics and Math Department of Novorossiysk University (Odessa). In two years he was expelled from the university for his participation in student political demonstrations. He continued his education abroad in Strasbourg where Professor Karl Ferdinand Braun involved Mandelshtam in his studies of electromagnetic waves. Mandelshtam received his doctoral degree there in 1902, taught applied physics and worked as Braun's assistant until 1913.

In 1914, on the eve of the First World War, Mandelshtam returned to Russia and lived from 1918 in Odessa, where he took an active part in the creation of the polytechnic institute. In 1925 he accepted the post of professor of theoretical physics in Moscow State University, where he worked to the end of his life. From 1934 he combined teaching with active research in the Physical Institutes in Moscow State University and Academy of Science.

Mandelshtam's scientific interests covered optics, radio-physics, theory of nonlinear waves and quantum mechanics. As early as1918, Mandelshtam predicted regular variation in the frequency of light scattering in crystals caused not by the motion of molecules, but by the thermal agitations of density. In 1928, experiments by Mandelshtam and Landsberg revealed the new effect. Because a similar publication by Indian scientists Raman and Krishnan appeared several months earlier; the phenomenon is often called the Raman Effect even though Mandelshtam not only observed it, but provided a fundamental explanation that lead to a breakthrough in theoretical physics.

Mandelshtam made a valuable contribution to quantum theory. In 1928, he and M.A.Leontovich created the theory of percolation of particles through the potential barrier and predicted the use of scattering matrixes.

Together with I.E.Tamm, Mandelshtam gave a more general treatment of time-energy inequality (what is now among the classics of the interpretation of quantum mechanics).

One of Mandelshtam's most interesting results, obtained together with N.D.Papaleksi in radio-physics and vibration theory, was the radio-interference method of precise measurement and its subsequent application in the radio-geodesy, radio-engineering, acoustics and aerodynamics. The study that began in 1918 led to the creation of the oscillators' theory, to the discovery of a new type of resonance - oscillation chains. The scientific merits of Mandelshtam's discoveries were highly esteemed by the scientific community.

Mandelshtam was also an outstanding organizer, lecturer and teacher. In Odessa, in the time of hunger and devastation after WWI and the Civil War, he drew to his work in the Polytechnic Institute such talented students as Papaleksi, Tamm, Aganin. Later, among his students were Gorelik, Rytov, Strelkov, Khaykin, and Leontovich.

Leonid Mandelshtam coined the term "correct idealization" - an idea being based upon accumulated experience, scent and intuition, the skill to separate essential from the unessential, without which any task becomes insolubly complex. Unfortunately, this art of the construction of fruitful physical models is practically unformulated and so it is possible to be trained in this approach only in the course of a long research association. For this very reason Mandelshtam gave so much attention and energy to the formation of creative associations with other scientists and to deliberating with them on the special features of physical thinking, which had very important consequences in the epoch of a scientific revolution in physics.

Leonid Isaakovich Mandelshtam died in Moscow on 27 November 1944. He lived in Belarus only in his early childhood and it is nice that this country didn't forget him.