In 1964, theoretical physicist Peter Higgs, who has died aged 94, proposed that the universe contained an all-pervading essence that could be manifested in the form of particles. This idea inspired governments to spend billions to find what became known as Higgs bosons.
The so-called “Higgs mechanism” controls the rate of thermonuclear fusion that powers the sun, but for which this engine of the solar system would have failed long before evolution had time to work its miracles on Earth. It is believed that the structure of atoms and matter and, probably, existence itself arises as a result of the mechanism, the truth of which was proven with the experimental discovery of the Higgs boson in 2012.
The Nobel Prize winning physicist Leon Lederman infamously described the boson as “the God particle”. Higgs, an atheist, found it inappropriate and misleading, but the name stuck and helped bring notoriety to the idea and to Higgs. He in turn became a Nobel Prize winner in 2013.
It was at Edinburgh University, as a young lecturer in mathematical physics in the early 1960s, that Higgs became interested in the profound and tantalizing ways in which properties – mathematical symmetries – in the equations that describe fundamental laws can be hidden in the structures that emerge.
For example, in space, unaffected by Earth’s gravity, a drop of water looks the same in all directions: it is spherically symmetric, consistent with the symmetry implied by the underlying mathematical equations that describe the behavior of water molecules. But when water freezes, the resulting snowflake takes on a different symmetry—its shape only looks the same when rotated by multiples of 60 degrees—even though the underlying equations remain the same.
The Japanese-American physicist Yoichiro Nambu first inspired interest in this phenomenon, known as spontaneous symmetry breaking, in 1960.
Inspired by Nambu’s work, Higgs’ own theory emerged in 1964 with his explanation of how equations requiring massless particles (such as the quantum theory of the electromagnetic field, which leads to the massless photon) could, via the so-called Higgs mechanism , give rise to particles with a mass.
This idea would later be at the root of Gerardus ‘t Hooft‘s explanation in 1971 of the weak force, responsible for radioactivity, where a massive “W” particle plays the analogous role to the massless photon. The subsequent discovery of the W in 1983 won Nobel prizes, both for the experiment and for theorists who envisioned it. Underlying this success was the so-called Higgs mechanism, which governed the mathematics in this explanation of the weak force.
When Nambu won the Nobel Prize in 2008, it seemed likely that the way was being prepared for Higgs’ eventual recognition.
A problem, however, as Higgs was always the first to stress, was that he was not alone in discovering the possibility of mass appearing “spontaneously”. Similar ideas have already been expressed: by the condensed matter physicist Philip Anderson, although in a more limited way, and by Robert Brout and François Englert in Belgium, who beat Higgs by a few weeks. A former colleague of Higgs at Imperial College, Tom Kibbleand two colleagues would write a paper along similar lines weeks later.
Where Higgs had fair claims to uniqueness was in the boson. He drew attention to the fact that in certain circumstances spontaneously broken symmetry implies that a massive particle must appear, whose affinity for interaction with other particles will be proportional to their masses.
It would be the discovery of this particle that could provide experimental verification that the theory is indeed a description of nature. Although even this boson was probably implicit in other work, it was Higgs who most sharply articulated its implications in particle physics.
The eponymous “Higgs boson” is the standard bearer for the Large Hadron Collider. In the early 1990s, science minister William Waldegrave issued his challenge: explain the Higgs boson on a sheet of paper and help me convince the government to fund it.
Among the winners, the most famous was the analogy, by David Miller of University College London, of Margaret Thatcher – a massive particle – wandering through a cocktail party at the Tory conference, gathering pendants as she goes. Higgs, whose politics were diametrically opposed to hers, expressed himself as “very comfortable” with the description.
He was always uncomfortable as a celebrity. When Cern – the European Organization for Nuclear Research – set to switch on the Large Hadron Collider (LHC) in 2008, the media promoted it as a search for the Higgs boson.
Higgs felt that Cern was misled to speak of “the” boson – he was always the first to point out that others had much the same idea and that it was unfair to name it after him. He once modestly described the detection of the boson as “tying up loose ends” and saw the main excitement of the LHC as its potential to reveal the secrets of dark matter and other kinds of new physics.
Nevertheless, in July 2012 Cern announced the discovery of a particle “with Higgs-like properties”. Media frenzy grew, and Higgs bravely accepted his fate as the center of attention.
Although most physicists were certain that the eponymous boson had been discovered, several months more study would be needed before full confirmation could be secured: the Nobel Prize for 2012 went elsewhere. By 2013, the evidence was compelling; there was a general expectation that 2013 would be the year.
By this point, 49 years had passed since Higgs wrote his first paper on the subject. In a final, nail-biting twist, the announcement of his long-awaited success was delayed by an hour as the Nobel committee struggled to reach the famously reclusive scientist. Aware of the media attention he was likely to receive, Higgs decided to be “somewhere else” when the announcement was made, telling colleagues he was planning a holiday in the north-west highlands of Scotland.
However, as the date approached, he realized that this was not a good plan for that time of year, so he decided to stay home and be somewhere else at the right time. At around 11am on October 8, he left home and by midday, when the announcement should have been made, he was in Leith, by the shore, in a bar called the Vintage, which Higgs says has both food and “quite sold good beer”. “.
With Higgs incommunicado (he largely avoided using cell phones or the Internet), after more than an hour of unsuccessful attempts to reach him, the Swedish Academy decided to make the public announcement anyway. The ironic result was that by 14:00, the news that Peter Higgs and Englert, of the Université Libre de Bruxelles, were the winners of the Nobel Prize for physics were known to the world, but not to Higgs himself. (Englert’s colleague Brout died in 2011, and could not be included as Nobel Prizes are not awarded posthumously.)
Higgs later recalled how, “after a suitable interval”, but still ignorant of the news, he made his way home from lunch. However, he delayed further by visiting an art exhibition, as “it seemed too early to get home, where reporters would probably be gathered”.
About three o’clock he was walking along Heriot Row, on his way to his flat in the next street, when a car stopped near Queen Street Gardens. A lady got out “in a very excited state” and told Higgs: “My daughter just called from London and told me about the award.” To which Higgs replied: “What award?” As he explained, he was joking, but that’s when his expectations were confirmed.
His plan was a success because, “I managed to get in my front door with no more damage than one photographer lying in wait.” A little over a decade later, the main focus of the LHC was to produce large numbers of Higgs bosons in order to understand the nature of the ubiquitous essence that forms them.
Higgs spent more than half a century as a theoretical physicist at the University of Edinburgh. Perhaps that is why he has been described in many media reports as a “Scottish physicist”, when in fact he was born in Newcastleof English parents, Thomas Ware Higgs and Gertrude Maud (nee Coghill).
His father was a sound engineer at the BBC, and the family moved almost immediately to Birmingham, where Peter spent his first 11 years. In 1941, with the Second World War intensifying, the BBC decided that Birmingham was too dangerous, and its operations were transferred to Bristol. The Higgs family duly moved there, with the intention of avoiding aerial bombardment, but the following weekend the center of Bristol was heavily bombed.
In Bristol, Higgs attended Cotham Grammar School, where a famous former pupil was the Nobel physicist Paul Dirac. Dirac’s name was prominent on the honors board. Higgs followed him, but initially in mathematics rather than physics. Higgs’ father had a collection of mathematics books, which inspired Peter and enabled him to be well ahead of the class. His interest in physics arose in 1946 when he met the Bristol physicists, later Nobel laureates, Cecil Powell and Neville Mott which describes the background of the atomic bomb program. Although it helped define his career, Higgs himself later became a member of CND.
At King’s College in London he studied theoretical physics and obtained his PhD in 1954. He worked on molecular physics and applied ideas of symmetry to molecular structure. His interests moved to particle physics, although his office was on the same corridor as that of Rosalind Franklin and Maurice Wilkinstwo of the co-discoverers of the structure of DNA, although his own work had no immediate link to their program.
He won research grants, first at the University of Edinburgh (1954-56), then in London at University College (1956–57), and at Imperial College (1957–58). He was appointed lecturer in mathematics at University College London in 1958, then moved to the University of Edinburgh in 1960, where he spent the rest of his research career. Initially a lecturer in mathematical physics, in 1970 he was appointed as a reader and in 1980 as a professor in theoretical physics. He was elected a Fellow of the Royal Society of Edinburgh in 1974, and FRS in 1983.
He met his future wife, the linguist Jody Williamson, at a CND meeting in 1960. They married in 1963 and had two sons, Christopher and Jonathan. Although they divorced in 1972, they remained friends until her death in 2008.
Higgs has won several awards in addition to the 2013 Nobel Prize. In addition to numerous honorary degrees, it has the 1997 Dirac medal and prize of the Institute of Physicsthe 2004 Wolf Prize in Physics, the Sakurai Prize of the American Physical Society in 2010, and the Edinburgh Medal in 2013. That year he was also appointed Companion of Honour, and two years later he received the Copley Medal of won the Royal Society, the world’s oldest scientific prize.
His sons survive him.
