← Back

Module 0 · Foundations

Paul Dirac & the ICTP Medal

1. Paul Adrien Maurice Dirac (1902–1984)

Dirac was born in Bristol on 8 August 1902 to a Swiss father and English mother. He arrived at quantum mechanics through electrical engineering, mathematics, and a year at Cambridge under R. H. Fowler. His 1926 doctoral thesis was the first complete formulation of quantum mechanics in noncommuting algebra; in 1928 he wrote down the Dirac equation:

\( (i \gamma^\mu \partial_\mu - m c) \psi = 0 \)

The equation reconciled special relativity with quantum mechanics, predicted electron spin \(\hbar/2\) as a relativistic consequence rather than an ad-hoc postulate, and — through its negative-energy solutions — predicted the existence of antimatter. Carl Anderson confirmed the positron in 1932; Dirac shared the 1933 Nobel Prize in Physics with Schrödinger at age 31.

Dirac was Lucasian Professor at Cambridge from 1932 to 1969 (the chair of Newton and later of Hawking), and spent his final fifteen years at Florida State University. His Principles of Quantum Mechanics (1930) remained a standard text for half a century. He was famously taciturn (“Of course” was usually the answer), preferred mathematical beauty as a guide to physical truth, and is one of the principal architects of the quantum-mechanical worldview.

2. ICTP & Abdus Salam

The International Centre for Theoretical Physics was founded in Trieste, Italy in 1964 by the Pakistani theoretical physicist Abdus Salam (Nobel 1979, with Glashow and Weinberg, for the electroweak unification). Salam’s explicit aim was to build an institution where physicists from developing countries could work alongside the international community without isolation. It is jointly operated by UNESCO, the IAEA, and the Italian government.

ICTP runs schools, workshops, conferences, an Associates programme that brings physicists from developing countries to Trieste regularly, and a graduate programme in collaboration with SISSA. Tens of thousands of researchers have passed through its doors. The Centre is now formally named the Abdus Salam International Centre for Theoretical Physics.

3. The Dirac Medal of ICTP

In 1985, on the centenary of quantum mechanics, ICTP established the Dirac Medal in Dirac’s memory. It is awarded annually on 8 August — Dirac’s birthday — to a theoretical physicist (or physicists, jointly) for outstanding contributions. The medal carries a US$5,000 honorarium — modest compared to the Wolf Prize (~$100k) or the Abel (~$700k) — but the international prestige is considerable.

The first Dirac Medals (1985) went to Yakov Zeldovich (cosmology, large-scale structure) and Edward Witten (string theory, quantum field theory; Witten was 33 at the time). Subsequent decades brought medals to a remarkable cross-section of late-20th and early-21st century theoretical physics: 't Hooft and Veltman (1989), Steven Weinberg, Richard Feynman, Stephen Hawking (1991, declined for reasons of policy), Maxim Kontsevich, John Bell, Cumrun Vafa, Joseph Polchinski, Andrew Strominger, Subir Sachdev, Duncan Haldane, Anne L'Huillier, Serge Haroche, and many more. Several Dirac medallists have subsequently received Nobel Prizes (Haroche 2012, Haldane 2016, Parisi 2021, L'Huillier 2023).

4. The Lectures of This Course

When awarded the Dirac Medal, laureates traditionally deliver a lecture at ICTP — usually two parts of about 60–90 minutes each — surveying their contribution and its place in the field. ICTP records and publishes these lectures on its YouTube channel, where they form an extraordinary archive of first-person accounts of modern theoretical physics. The next three modules (M1–M3) embed 14 of these lectures (28 video parts), grouped by theme:

← OverviewModule 1 →