Richard Q. Twiss
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Richard Quintin Twiss (24 August 1920 – 20 May 2005) was a British astronomer. He is known for his work on the
Hanbury-Brown and Twiss effect In physics, the Hanbury Brown and Twiss (HBT) effect is any of a variety of correlation and anti-correlation effects in the intensities received by two detectors from a beam of particles. HBT effects can generally be attributed to the wave–par ...
with
Robert Hanbury Brown Robert Hanbury Brown, AC FRS (31 August 1916 – 16 January 2002) was a British astronomer and physicist born in Aruvankadu, India. He made notable contributions to the development of radar and later conducted pioneering work in the field of ...
. It led to the development of the Hanbury Brown-Twiss intensity
interferometer Interferometry is a technique which uses the ''interference'' of superimposed waves to extract information. Interferometry typically uses electromagnetic waves and is an important investigative technique in the fields of astronomy, fiber op ...
in the UK in 1954. Their work appeared to contradict the established beliefs about
quantum interference In physics, interference is a phenomenon in which two waves combine by adding their displacement together at every single point in space and time, to form a resultant wave of greater, lower, or the same amplitude. Constructive and destructive ...
, and he and Brown received the
Eddington Medal The Eddington Medal is awarded by the Royal Astronomical Society for investigations of outstanding merit in theoretical astrophysics. It is named after Sir Arthur Eddington. First awarded in 1953, the frequency of the prize has varied over the year ...
of the
Royal Astronomical Society (Whatever shines should be observed) , predecessor = , successor = , formation = , founder = , extinction = , merger = , merged = , type = NGO ...
for it in 1968.


Life

Richard Twiss was born in
Simla Shimla (; ; also known as Simla, the official name until 1972) is the capital and the largest city of the northern Indian state of Himachal Pradesh. In 1864, Shimla was declared as the summer capital of British India. After independence, the ...
in
India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
but was educated in
England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...
. He read
mathematics Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics ...
at
Cambridge Cambridge ( ) is a university city and the county town in Cambridgeshire, England. It is located on the River Cam approximately north of London. As of the 2021 United Kingdom census, the population of Cambridge was 145,700. Cambridge bec ...
, completing the
Mathematical Tripos The Mathematical Tripos is the mathematics course that is taught in the Faculty of Mathematics at the University of Cambridge. It is the oldest Tripos examined at the University. Origin In its classical nineteenth-century form, the tripos was a ...
with distinction, but his early contributions were to the theory of
radar Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...
and basic
electronics The field of electronics is a branch of physics and electrical engineering that deals with the emission, behaviour and effects of electrons using electronic devices. Electronics uses active devices to control electron flow by amplification ...
. His work in this area was included in the famous "five foot shelf"—a series of reference books in
electronic engineering Electronics engineering is a sub-discipline of electrical engineering which emerged in the early 20th century and is distinguished by the additional use of active components such as semiconductor devices to amplify and control electric current ...
compiled at
MIT The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the m ...
that was the circuit designer's bible in the 1950s. He was awarded a
Doctor of Science Doctor of Science ( la, links=no, Scientiae Doctor), usually abbreviated Sc.D., D.Sc., S.D., or D.S., is an academic research degree awarded in a number of countries throughout the world. In some countries, "Doctor of Science" is the degree used f ...
degree by MIT in 1949. Twiss went on to help construct the
Narrabri Stellar Intensity Interferometer The Narrabri Stellar Intensity Interferometer (NSII) was the first astronomical instrument to measure the diameters of a large number of stars at visible wavelengths. It was designed by (amongst others) Robert Hanbury Brown, who received the Hughe ...
. Observations with the interferometer began in 1965. Measurements made between 1965 and 1974 were used to establish the temperature scale for stars hotter than the Sun and this scale is still in use. The intensity interferometer has a very poor signal-to-noise ratio compared to the classical " Michelson" stellar interferometer. Twiss decided to pursue the Michelson alternative at the National Physical Laboratory at
Teddington Teddington is a suburb in south-west London in the London Borough of Richmond upon Thames. In 2021, Teddington was named as the best place to live in London by ''The Sunday Times''. Historically in Middlesex, Teddington is situated on a long m ...
in the UK. John Davis worked with him for a short while on this project. When the
Royal Observatory, Edinburgh The Royal Observatory, Edinburgh (ROE) is an astronomical institution located on Blackford Hill in Edinburgh. The site is owned by the Science and Technology Facilities Council (STFC). The ROE comprises the UK Astronomy Technology Centre (UK&nbs ...
established its outstation at
Monte Porzio Catone Monte Porzio Catone is a ''comune'' (municipality) in the Metropolitan City of Rome in the central Italian region Latium, located about southeast of Rome, on the Alban Hills. Monte Porzio Catone borders the following municipalities: Frascati, Gro ...
just south of
Rome , established_title = Founded , established_date = 753 BC , founder = King Romulus (legendary) , image_map = Map of comune of Rome (metropolitan city of Capital Rome, region Lazio, Italy).svg , map_caption ...
, Twiss decided to move his Michelson interferometer there. Not only was the weather more conducive to astronomy, the food and wine were much superior to what was available in Teddington!
Speckle interferometry Speckle imaging describes a range of high-resolution astronomical imaging techniques based on the analysis of large numbers of short exposures that freeze the variation of atmospheric turbulence. They can be divided into the shift-and-add ("'' ...
was discovered during that period by Antoine Labeyrie. This stimulated a renewed interest around the world in interferometry. In particular, John Davis and Hanbury Brown became convinced that a Michelson interferometer would be cheaper to build and have superior performance to a new intensity interferometer. In the mid-1970s Twiss's non-scientific interests gradually took over and he effectively retired from active involvement in science. In the 1970s he made it clear that he regarded
Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
as a colonial backwater. His reaction when told that William J. Tango was going to join Davis and Brown in Sydney was typical. "But William," he said, "they eat peas out of tins!" In spite of that, a few years before his death Twiss visited Australia and fell in love with it. In 2004 he applied for permanent residence. He died on 20 May 2005. He is mentioned in the book "Boffin : A Personal Story of the Early Days of Radar, Radio Astronomy and Quantum Optics" , by Hanbury Brown He was awarded the
Albert A. Michelson Medal The Franklin Institute is a science museum and the center of science education and research in Philadelphia, Pennsylvania. It is named after the American scientist and wikt:statesman, statesman Benjamin Franklin. It houses the Benjamin Franklin ...
of the
Franklin Institute The Franklin Institute is a science museum and the center of science education and research in Philadelphia, Pennsylvania. It is named after the American scientist and statesman Benjamin Franklin. It houses the Benjamin Franklin National Memori ...
in 1982, jointly with
Robert Hanbury Brown Robert Hanbury Brown, AC FRS (31 August 1916 – 16 January 2002) was a British astronomer and physicist born in Aruvankadu, India. He made notable contributions to the development of radar and later conducted pioneering work in the field of ...
.


Twiss Parameters

In
accelerator physics Accelerator physics is a branch of applied physics, concerned with designing, building and operating particle accelerators. As such, it can be described as the study of motion, manipulation and observation of relativistic charged particle beams ...
, a method of describing the properties of a beam has become known as ''Twiss Parameters''. While this is a reference to Richard Twiss, it is unclear (including to Twiss himself) how his name became associated with the formulation, as the parameters were developed by
Ernest Courant Ernest Courant (March 26, 1920 – April 21, 2020) was an American accelerator physicist and a fundamental contributor to modern large-scale particle accelerator concepts. His most notable discovery was his 1952 work with Milton S. Livingston a ...
and
Hartland Snyder Hartland Sweet Snyder (1913, Salt Lake City – 1962) was an American physicist who along with Robert Oppenheimer calculated the gravitational collapse of a pressure-free sphere of dust particles as described by Einstein's general relativity, and f ...
, and are more accurately referred to as the Courant–Snyder parameters.


Notes


References

* * * {{DEFAULTSORT:Twiss, Richard Q. 20th-century British astronomers Optical physicists 1920 births 2005 deaths British people in colonial India British expatriates in the United States Alumni of the University of Cambridge Massachusetts Institute of Technology alumni