U.K. Society Lauds USC College Physics Professor

Clifford Johnson recognized by the Institute of Physics for his contributions to science

October 2004

USC College’s Clifford Johnson has received the 2005 Maxwell Medal and Prize from the leading physics society in the United Kingdom.

The Institute of Physics medal recognizes Johnson’s outstanding contribution to string theory, quantum gravity and its interaction with strongly coupled field theory. In particular, he was honored for his work understanding singularities and the thermodynamic properties of quantum space-time.

Johnson, professor of physics and astronomy, taught at the University of Durham before joining the USC faculty in 2003 as part of the College’s Senior Faculty Hiring Initiative.

“The awards recognize outstanding achievements by physicists in their respective fields,” says Paul Danielsen, director of strategy, communications and business at the Institute of Physics. In addition to Johnson’s award, the Institute honored scientists this year for pioneering work on detecting climate change and new methods to study the properties of soft condensed matter.

“Previous winners constitute a roll call of those who have shaped physics in the 20th century. This year’s winners demonstrate that U.K. physicists continue to make remarkable contributions into the 21st century,” Danielsen says.

The Institute of Physics — an international society with more than 37,000 members — promotes the science of physics, pure and applied.

“We are delighted to hear of his well-deserved recognition,” says Gene Bickers, professor and chair of physics and astronomy in the College. Bickers says that some of the most well-known winners of the Maxwell Medal include scientists Abdus Salam and Anthony Leggett, who both went on to win Nobel Prizes, as well as Stephen Hawking.

Johnson considers the medal a great honor. “It is exciting to be associated with so many truly remarkable physicists who received this prize in the past,” Johnson says. “Of course, I could not have achieved this without the support of my family, my wife and my colleagues and collaborators in the field.”

Johnson has been studying superstring theory since the late 1980s. String theory, one of the most active fields in contemporary physics, attempts to unify gravity, electromagnetism, the strong nuclear force and the weak nuclear force — the four forces of nature — within a single mathematical framework.

Johnson applies quantum theory to the study of the fundamental constituents of the universe, focusing on situations in which these constituents are interacting strongly with each other.

“It is in this way that you can describe important objects such as black holes, and the very early universe, where gravity is so strong that the classical theory of Einstein breaks down, producing what is known as a ‘singularity.’ That’s where the physics stops making sense,” says Johnson.

The Institute specifically cited Johnson’s research that showed that string theory provides physical descriptions of some of these singularities, resolving them into what he calls “sensible” physical objects.

These same techniques developed by Johnson have also proved useful in a related area addressed by string theory, called gauge theories.

“Progress in this area would be exciting because these theories are known to describe how the building blocks of familiar matter (photons, electrons, quarks and more) work together, which get into phenomena such as the binding of quarks with each other. That’s considered by physicists to be one of the most important current problems to understand in nature,” he says.

Johnson is the author of D-Branes (Cambridge, 2002), the leading text on a key theoretical tool used in the string theory field.