Tuesday 24 July 2012

INDIAN SCIENTIST SATYANDRA NATH BOSE

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Satyendra Nath Bose
সত্যেন্দ্র নাথ বসু

Satyendra Nath Bose in 1925
Born 1 January 1894
Calcutta
, British India (now Kolkata)
Died 4 February 1974 (aged 80)
Calcutta, India (now Kolkata)
Residence India
Nationality Indian
Fields Physics and Mathematics
Institutions University of Calcutta
Alma mater University of Calcutta
Known for Bose–Einstein condensate
Bose–Einstein statistics

Bose gas
Notable awards Padma Vibhushan
Fellow of the Royal Society
[1]
Satyendra Nath Bose FRS[1] (Bengali: সত্যেন্দ্র নাথ বসু Shottendronath Boshū, IPA: [ʃot̪ːend̪ronat̪ʰ boʃu]; 1 January 1894 – 4 February 1974) was an Indian physicist specializing in mathematical physics. He was born in Kolkata, then spelt Calcutta. He is best known for his work on quantum mechanics in the early 1920s, providing the foundation for Bose–Einstein statistics and the theory of the Bose–Einstein condensate. A Fellow of the Royal Society, he was awarded India's second highest civilian award, the Padma Vibhushan in 1954 by the Government of India.[2][3][4]
The class of particles that obey Bose-Einstein statistics, bosons, was named after him[5][6][7] by Paul Dirac.[8]
A self-taught scholar and a polyglot, he had a wide range of interests in varied fields including physics, mathematics, chemistry, biology, mineralogy, philosophy, arts, literature and music. He served on many research and development committees in independent India.[9]

Contents

Early life

Bose was born in Calcutta now Kolkata, West Bengal, India, the eldest of seven children. He was the only son, with six sisters after him. His ancestral home was in village Bara Jagulia, in the District of Nadia, about 48 kilometers from Calcutta. His schooling began at the age of five. His first school was near his home. Later, when his family moved to Goabagan, he was admitted to the New Indian School. In the final year of school, he was admitted to the Hindu School. He passed his entrance examination (matriculation) in 1909 and stood fifth in the order of merit. He next joined the intermediate science course at the Presidency College, Calcutta, where he was taught by illustrious teachers as Jagadis Chandra Bose and Prafulla Chandra Ray. Meghnad Saha came from Dacca (Dhaka) and joined the same college two years later. P C Mahalanobis and Sisir Kumar Mitra were a few years senior to them. Satyendra Nath Bose chose mixed (applied) mathematics for his B.Sc. and passed the examinations standing first in 1913 and again stood first in the M.Sc. mixed mathematics exam in 1915. It is said that his marks in the M.Sc. examination created a new record in the annals of the University of Calcutta, which is yet to be surpassed.[10]
After completing his M.Sc., Bose joined the University of Calcutta, Calcutta as a research scholar in 1916 and started his studies in the theory of relativity. It was an exciting era in the history of scientific progress. The quantum theory had just appeared on the horizon and important results had started pouring in.[10]
His father, Surendranath Bose, worked in the Engineering Department of the East Indian Railway Company. He married Ushabati at the age of 20.[11] They had nine children. Two of them died in their early childhood. When he died in 1974, he left behind his wife, two sons, and five daughters. [10]
As a polyglot, he was well versed in several languages such as Bengali, English, French, German and Sanskrit as well as poetry of Lord Tennyson, Rabindranath Tagore and Kalidasa. He could also play the esraj, a musical instrument similar to a violin. He was actively involved in running night schools that came to be known as the Working Men's Institute.[4][12]

Research career

Bose attended Hindu School in Calcutta, and later attended Presidency College, also in Calcutta, earning the highest marks at each institution while fellow student Meghnad Saha came second.[4] He came in contact with teachers such as Jagadish Chandra Bose and Prafulla Chandra Roy who provided inspiration to aim high in life. From 1916 to 1921, he was a lecturer in the physics department of the University of Calcutta. Along with Saha, Bose prepared the first book in English based on German and French translations of original papers on Einstein's special and general relativity in 1919. In 1921, he joined as Reader of the department of Physics of the then recently founded University of Dhaka (now in Bangladesh) by the then Vice Chancellor of University of Calcutta Sir Ashutosh Mukherjee, himself a distinguished mathematician, a high court judge, and with strong interest in physics. Bose set up whole new departments, including laboratories, to teach advanced courses for M.Sc. and B.Sc. honors and taught thermodynamics as well as James Clerk Maxwell's theory of electromagnetism.[13]
Satyendra Nath Bose, along with Saha, presented several papers in theoretical physics and pure mathematics from 1918 onwards. In 1924, while working as a Reader at the Physics Department of the University of Dhaka, Bose wrote a paper deriving Planck's quantum radiation law without any reference to classical physics by using a novel way of counting states with identical particles. This paper was seminal in creating the very important field of quantum statistics. Though not accepted at once for publication, he sent the article directly to Albert Einstein in Germany. Einstein, recognizing the importance of the paper, translated it into German himself and submitted it on Bose's behalf to the prestigious Zeitschrift für Physik. As a result of this recognition, Bose was able to work for two years in European X-ray and crystallography laboratories, during which he worked with Louis de Broglie, Marie Curie, and Einstein.[4][14][15][16]
After his stay in Europe, Bose returned to Dhaka in 1926. He was made Head of the Department of Physics. He continued guiding and teaching at Dhaka University. Bose designed equipments himself for a X-ray crystallography laboratory. He set up laboratories and libraries to make the department a center of research in X-ray spectroscopy, X-ray diffraction, magnetic properties of matter, optical spectroscopy, wireless, and unified field theories. He also published an equation of state for real gases with Meghnad Saha. He was also the Dean of the Faculty of Science at Dhaka University until 1945. When the partition of India became imminent, he returned to Calcutta to take up the prestigious Khaira Chair and taught at University of Calcutta until 1956. He insisted every student to design his own equipment using local materials and local technicians. He was made professor emeritus on his retirement.[14][17][4] He then became Vice Chancellor of Visva-Bharati University in Shanti Niketan. He returned to the University of Calcutta to continue research in nuclear physics and complete earlier works in organic chemistry. In subsequent years, he worked in applied research such as extraction of helium in hot springs of Bakreshwar.[18]
Apart from physics, he did some research in biotechnology and literature (Bengali, English). He made deep studies in chemistry, geology, zoology, anthropology, engineering and other sciences. Being a Bengali, he devoted a lot of time to promoting Bengali as a teaching language, translating scientific papers into it, and promoting the development of the region.[15][19][3]

Bose–Einstein statistics

Possible outcomes of flipping two coins
Two heads Two tails One of each
There are three outcomes. What is the probability of producing two heads?
Outcome probabilities
  Coin 1
Head Tail
Coin 2 Head HH HT
Tail TH TT
Since the coins are distinct, there are two outcomes which produce a head and a tail. The probability of two heads is one-quarter.
While presenting a lecture[20] at the University of Dhaka on the theory of radiation and the ultraviolet catastrophe, Bose intended to show his students that the contemporary theory was inadequate, because it predicted results not in accordance with experimental results. During this lecture, Bose committed an error in applying the theory, which unexpectedly gave a prediction that agreed with the experiment.
Bose's letter
The error was a simple mistake—similar to arguing that flipping two fair coins will produce two heads one-third of the time—that would appear obviously wrong to anyone with a basic understanding of statistics. However, the results it predicted agreed with experiment, and Bose realized it might not be a mistake after all. He, for the first time, took the position that the Maxwell–Boltzmann distribution would not be true for microscopic particles where fluctuations due to Heisenberg's uncertainty principle will be significant. Thus he stressed the probability of finding particles in the phase space, each state having volume h3, and discarding the distinct position and momentum of the particles.
Bose adapted this lecture into a short article called "Planck's Law and the Hypothesis of Light Quanta" and sent it to Albert Einstein with the following letter:[21]
“Respected Sir, I have ventured to send you the accompanying article for your perusal and opinion. I am anxious to know what you think of it. You will see that I have tried to deduce the coefficient 8π ν2/c3 in Planck’s Law independent of classical electrodynamics, only assuming that the ultimate elementary region in the phase-space has the content h3. I do not know sufficient German to translate the paper. If you think the paper worth publication I shall be grateful if you arrange for its publication in Zeitschrift für Physik. Though a complete stranger to you, I do not feel any hesitation in making such a request. Because we are all your pupils though profiting only by your teachings through your writings. I do not know whether you still remember that somebody from Calcutta asked your permission to translate your papers on Relativity in English. You acceded to the request. The book has since been published. I was the one who translated your paper on Generalised Relativity.”
Einstein agreed with him, translated Bose's paper "Planck's Law and Hypothesis of Light Quanta" into German, and saw to it that it was published in Zeitschrift für Physik under Bose's name, in 1924.[22]
The reason Bose's "mistake" produced accurate results was that since photons are indistinguishable from each other, one cannot treat any two photons having equal energy as being two distinct identifiable photons. By analogy, if in an alternate universe coins were to behave like photons and other bosons, the probability of producing two heads would indeed be one-third (tail-head = head-tail). Bose's "error" is now called Bose–Einstein statistics. This result derived by Bose laid the foundation of quantum statistics, as acknowledged by Einstein and Dirac.[22]
Velocity-distribution data of a gas of rubidium atoms, confirming the discovery of a new phase of matter, the Bose–Einstein condensate.[23] Left: just before the appearance of a Bose–Einstein condensate. Center: just after the appearance of the condensate. Right: after further evaporation, leaving a sample of nearly pure condensate.
Einstein adopted the idea and extended it to atoms. This led to the prediction of the existence of phenomena which became known as Bose-Einstein condensate, a dense collection of bosons (which are particles with integer spin, named after Bose), which was demonstrated to exist by experiment in 1995.
Although several Nobel Prizes were awarded for research related to the concepts of the boson, Bose–Einstein statistics and Bose–Einstein condensate—the latest being the 2001 Nobel Prize in Physics given for advancing the theory of Bose–Einstein condensates—Bose himself was not awarded the Nobel Prize.
In his book, The Scientific Edge, the noted physicist Jayant Narlikar observed:
S. N. Bose’s work on particle statistics (c. 1922), which clarified the behaviour of photons (the particles of light in an enclosure) and opened the door to new ideas on statistics of Microsystems that obey the rules of quantum theory, was one of the top ten achievements of 20th century Indian science and could be considered in the Nobel Prize class.[24]
However, when asked about the omission, Bose himself said:
I have got all the recognition I deserve.[25]

Honors

In 1937, Rabindranath Tagore dedicated his only book on science, Visva-Parichay, to Satyendra Nath Bose. Bose was honored with title Padma Vibhushan by the Indian Government in 1954. In 1959, he was appointed as the National Professor, the highest honor in the country for a scholar, a position he held for 15 years. In 1986, S.N. Bose National Centre for Basic Sciences was established by an act of Parliament, Government of India, in Salt Lake, Calcutta in honor of the world-renowned Indian scientist.[26][27]
Bose became an adviser to then newly-formed Council of Scientific and Industrial Research. He was the President of Indian Physical Society and the National Institute of Science. He was elected General President of the Indian Science Congress. He was the Vice President and then the President of Indian Statistical Institute. In 1958, he became a Fellow of the Royal Society. He was nominated as member of Rajya Sabha.
Partha Ghose has stated that[4]
Bose’s work stood at the transition between the 'old quantum theory' of Planck, Bohr and Einstein and the new quantum mechanics of Schrodinger, Heisenberg, Born, Dirac and others.

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