Satyendra Nath Bose: The Physicist Behind the Boson

Bose was an Indian theoretical physicist. His 1924 idea about light is now part of every quantum physics course.

Where did he come from?

• He was born in Calcutta on 1 January 1894.
• He was the eldest of seven children.
• He studied at Presidency College, Calcutta.
• He came first in the intermediate science exam of 1911.
• He came first again in the BSc of 1913. Meghnad Saha stood second.
• He finished his MSc in 1915.

How did he learn physics?

Bose and Saha had formal physics training only up to the BSc. They taught themselves modern physics. They even translated Einstein’s papers on relativity from German into English.

What is the memory hook?

Think “1894 born, 1913 first, 1924 famous”. Saha was his friend and rival at college.

In 1924 Bose was a Reader at the University of Dacca. He wrote a short paper on Planck’s law of radiation.

What was new in it?

Planck’s law describes the light that hot objects give off. Earlier derivations mixed in ideas from classical physics. Bose derived the law using only the idea of light quanta, treated in a new statistical way.

What happened to the paper?

• Bose sent it to the Philosophical Magazine early in 1924.
• After about six months the referees gave negative reports.
• He then sent the rejected paper to Albert Einstein.
• Einstein translated it into German himself.
• It appeared in the Zeitschrift für Physik, with a note from Einstein.

What did Einstein write?

Einstein called Bose’s derivation “an important advance”. He added that the same method also gives a quantum theory of the ideal gas.

What is the memory hook?

Think “rejected, then Einstein”. The paper was only four pages long.

Bose’s method counts identical particles in a new way. This method is now called Bose-Einstein statistics.

What is the key idea?

• Photons of the same kind cannot be told apart.
• Counting them as identical gives Planck’s law.
• Einstein extended the idea to a gas of atoms.

What is a boson?

A boson is a particle that follows Bose-Einstein statistics. Paul Dirac named such particles bosons in Bose’s honour. A particle with whole-number spin is a boson. A photon is one example.

What is the memory hook?

Think “Bose, so boson”. The name comes from Bose, not from Einstein.

Einstein followed Bose’s idea to a surprising prediction. Cool a gas of bosons close to absolute zero. The atoms then settle into the lowest energy state together.

What does the condensate look like?

• The atoms overlap and act like one “super atom”.
• This is called a Bose-Einstein condensate, or BEC.
• It is often called a new state of matter.

When was it first made?

• The first BEC was made at JILA, Boulder, on 5 June 1995.
• Eric Cornell and Carl Wieman led the team.
• They used about 2,000 rubidium atoms.
• Wolfgang Ketterle made one with sodium atoms at MIT a few months later.

Did anyone win a Nobel Prize?

Yes. The 2001 Nobel Prize in Physics went to Cornell, Ketterle and Wieman. Bose himself never won a Nobel Prize.

What is the memory hook?

Think “predicted 1924, made 1995, Nobel 2001”. The wait was seventy years.

Bose spent most of his working life in Dacca and Calcutta. Honours came late but they were many.

What was his career path?

• 1921: Reader in physics at the University of Dacca.
• 1927: Professor and head of the department at Dacca.
• 1944: General President of the Indian Science Congress.
• 1945: moved to the University of Calcutta.
• 1956: retired, then became Vice-Chancellor of Visva-Bharati.

What honours did he receive?

• 1954: the Padma Vibhushan.
• 1958: Fellow of the Royal Society.
• 1959: National Professor, held for 15 years.
• He died on 4 February 1974.

Who dedicated a book to him?

Rabindranath Tagore dedicated his science book Visva-Parichay to Bose in 1937. It explains the universe in simple Bengali.

What is the memory hook?

Think “54 Padma, 58 Royal Society, 59 National Professor”. Climb the years in order.

Two earlier papers asked about his work. One was a descriptive Mains question. The other was an objective question on the condensate.

What did the UPSC Mains ask?

How do you answer it?

• Start with the 1924 derivation of Planck’s law.
• Mention Einstein’s translation and his gas theory.
• Add bosons and the 1995 condensate.
• Close with the 2001 Nobel Prize for the condensate.

What did the CDS ask?

The correct choice is (b). It is called the fifth state of matter, after solid, liquid, gas and plasma.

What is the memory hook?

Think “Mains wants the story, CDS wants the state”. Prepare both.

Four mix-ups come up again and again. Learn each pair.

What are the traps?

• Which Bose? Satyendra Nath Bose is the boson physicist. Jagadish Chandra Bose worked on radio waves and plants.
• Bose or Einstein? Bose gave the 1924 statistics. Einstein extended them to atoms and predicted the condensate.
• Who won the Nobel? Cornell, Ketterle and Wieman won in 2001. Bose never did.
• Which year? The condensate was made in 1995. The paper dates from 1924.

How do you remember them?

Think “Bose counts, Einstein predicts, Cornell and Wieman build”. Match each name to its job.