Robert G. Leigh

Robert Graham Leigh, Professor of High Energy Physics at the University of Illinois, passed away on April 18, 2026 at his home in Champaign, Illinois, USA, at the age of 61, from a glioblastoma (malignant brain tumor). He is survived by his wife of 38 years, Kimberly Anne Leigh, their two children, Joseph Robert Leigh (wife Madeleine Elizabeth Garvey) and Jennifer Rose Leigh, all residing in Champaign, IL, as well as his brother, John Douglas Leigh (wife Linda Louise Leigh) of Chatham, Ontario, Canada. Rob was the son of the late Cecil Henry Leigh and Doreen Margaret “Peggy” Leigh, also of Chatham, Ontario. Rob was preceded in death by his brother, William James Leigh, and his sister, Mary Elizabeth Wild. Rob was also survived by William’s wife, Patricia Jo-Anne Leigh and Mary’s husband Richard James Wild, as well as many nieces, nephews, grandnieces, and grandnephews.

Rob was born in Chatham, Ontario, Canada, on April 23, 1964. He graduated Valedictorian from John McGregor Secondary School in Chatham in 1986 and then received his Bachelor of Science degree in Theoretical Physics from the University of Guelph in 1986; his advisor was Professor George Leibbrandt. In 1986, Rob was awarded a four-year Natural Sciences and Engineering Research Council of Canada (NSERC) Postgraduate Scholarship, when he went on to earn his PhD in theoretical particle physics from the University of Texas at Austin in 1991 working with Professor Joe Polchinski. His doctoral dissertation was titled “Topics in String Duality, CP Violation, and Baryogenesis.” Rob then held postdoctoral research appointments at the Institute for Particle Physics at the University of California, Santa Cruz, and at Rutgers University in New Jersey. He joined the Department of Physics at the University of Illinois Urbana-Champaign in 1996 as an Assistant Professor. He was promoted to Associate Professor in 2002 and then full Professor in 2008. From 2002-2003, he took a sabbatical as a Scientific Asssociate at the European Organization for Nuclear Research (CERN—Conseil Européen pour la Recherche Nucléaire), in Geneva, Switzerland. In 2010, Rob became an associate of the Center for Advanced Study at the University of Illinois; he was also a member of the Illinois Quantum Information Science and Technology Center (IQUIST) in the Grainger College of Engineering at the University of Illinois. From 2011-2012, 2018-2019, and 2023-2025, he was a Visiting Researcher at the Perimeter Institute for Theoretical Physics in Waterloo, Ontario, Canada.

Rob did outstanding work in string theory, supersymmetric field theory, and other topics in particle physics and early universe cosmology. His work still lies at the heart of current efforts to build a fundamental theory of matter, including quantum gravity effects.

In his first scientific papers, Rob wrote about his discovery of D-branes (Dirichlet membranes) and orientifolds in string theory and the first example of superstring duality, and derived the Dirac-Born-Infeld action describing the dynamics of D-branes. The study of D-branes is fundamental to modern string theory and its applications to particle physics, mathematics and condensed matter physics. His research interests in his final years included the application of holographic string theory methods to study particle physics, gravity and condensed matter physics.

Throughout his career, Rob had been recognized as a world-class physicist with encyclopedic knowledge of the subject and taught his students by example on how to be a confident theoretical physicist; he had high standards for what he considered good work and insisted that his students meet those standards while still connecting with his students on a personal level, thus earning respect and admiration from his students. From 1997-2000, Rob was named Outstanding Junior Investigator by the US Department of Energy. In December of 2004, the University of Illinois Urbana-Champaign awarded Rob with the Arnold O. Beckman Award, a research support award. In 2007, Rob became a Fellow of the American Physical Society.

For most of Rob’s life, he was a hockey fan and an avid stamp collector, and later in life amassed sizeable collections of historical postcards, postmarks, stamps, and hockey cards. For many years he was a member of and held multiple positions in the Champaign-Urbana Stamp Club. He also contributed significantly to Canadian philately, particularly to postal history, for over 20 years. He was heavily involved in the Postal History Society of Canada (PHSC) and was its Webmaster from 2006 until shortly before he passed away. He not only developed and maintained their website but also built and maintained several postmark databases and other postal history research tools. Rob was also Vice-President of this society from 2010 to 2025 and Director for several years before that.

He was elected Fellow of the Postal History Society of Canada on July 21, 2018.

Rob was the Webmaster of the ORAPEX (Ottawa Regional Association of Philatelic Exhibitions) National level show from 2006 to 2025.

He exhibited postal history at the National level and won numerous awards, including several Grand Awards. One of his highest accomplishments was for his exhibit The Western District of Upper Canada: The Development of Postal Communications and Postal Markings which won the APS (American Philatelic Society) World Series of Philately Prix d’Honneur in 2018 (Columbus) and 2019 (Omaha).

His major philately exhibitions included:

- The Western District of Upper Canada: The Development of Postal Communications and Postal Markings, 1800-1850

- The Bickerdike Postmarking Machines of Hamilton, 1897-1902

- The Early Machine Cancels of Canada 1896-1902

- The 1935 Special Delivery Issue of Canada

Rob wrote over a dozen postal history articles in BNA Topics, the PHSC Journal, Maple Leaves and the American Philatelist, as well as two BNAPS (British North America Philatelic Society Ltd.) Exhibit Series publications.

One of his articles, Canada’s Stampless Era: a Glimpse into Canada’s Early Postal History published in the American Philatelist, received the 2023 PHSC Frank W. Campbell Award for most outstanding Canadian/BNA postal history publication not published in the PHSC Journal. [published in the American Philatelist. vol. 137, no. 8 (August 2023), pp. 698-704]

In September 2025, Rob was awarded a Lifetime Achievement Award by the British North America Philatelic Society, for which he was very grateful. The philatelic community was a large part of Rob’s life in which he earned the respect and friendship of many involved.

Rob’s family (and Rob) would like to thank everyone for all their care, concern, and support over the past year while navigating the unexpected and heartbreaking journey of Rob’s illness. Whether family, friend, work colleague, or former student, your support has meant more than can be expressed.

To honor his contributions to the field of Physics, A Celebration of Life will be held 12 noon on Wednesday, April 22, 2026 at the Loomis Physics Building, 1110 West Green Street, Urbana. 

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