Helen Rhoda Quinn

Helen Rhoda Quinn
Helen Rhoda Quinn
  • From:

    Stanford University and SLAC National Accelerator Laboratory │Stanford, California

  • Year:


  • Subject:


  • Award:

    Benjamin Franklin Medal

  • Citation:

    For her pioneering contributions to the long-term quest for a unified theory of the strong, weak, and electromagnetic interactions of fundamental particles.

Helen Rhoda Quinn began her career as one of the few female physicists in the world, following her love of math and science from the Australian bush to Stanford University. Her groundbreaking work picked up where Einstein left off, tackling the holy grail of theoretical physics: the Theory of Everything. And when we say “everything,” we mean everything: the whole universe.

To most people, theoretical physics is the epitome of complexity—a dizzying assortment of theories, particles, and forces with exotic names, represented by complex mathematical formulas. Yet it is really all about simplicity: seeking to explain the universe as elegantly as possible, perhaps even with a single equation that would ultimately explain everything. In a real sense, it is about going back in time to the very beginnings of the universe, when everything truly was all the same.

Appropriately enough, such a theory is often called a "theory of everything," or, in more scientific terms, a Grand Unified Theory. It has been something of a Holy Grail for physicists at least since Einstein, who famously spent his life striving and failing to achieve it. But scientists have nevertheless enjoyed great success in at least partly describing the interrelationships between the four fundamental forces of nature: gravity, electromagnetism, and the strong and weak nuclear forces. Yet the grand unification, the theory of everything, remains maddeningly elusive. One primary challenge is unifying the strong, weak, and electromagnetic forces—a quest in which theoretical physicist Helen Quinn has made major contributions over her long and distinguished career.

Quinn did not start out intending to become one of the world's leading theoretical physicists, despite an early talent for math and science. Such notions were unheard of for a woman growing up in Australia in the 1950s, especially for one at her all-girls school surrounded by 50 acres of bushland. Instead, she thought perhaps she would be a meteorologist or a high school science teacher. After beginning her studies at Melbourne University, she emigrated to the U.S. with her family and transferred to Stanford University, where she changed her major to physics. The fact that there were no women faculty and hardly any female students in the Stanford Physics Department at that time did not stop her. She had discovered a new path for her passion for mathematics, and with the Stanford Linear Accelerator Laboratory (now Stanford Linear Accelerator Center or SLAC) nearby, she found herself in a hotbed of exciting theoretical and experimental discovery. Quinn was determined to be part of it.

After earning her doctorate in 1967, she moved on to a post-doctoral position at the DESY Synchrotron Laboratory in Germany before settling into a fellowship and then professorial positions at Harvard University. She returned to Stanford in 1976 to accept a professorship at SLAC. Throughout her career, Quinn has made vital contributions to physics, particularly in three crucial aspects necessary for a Grand Unified Theory (GUT) of the strong, weak, and electromagnetic interactions.

In 1974, working with future Franklin Institute Medalist Steven Weinberg and Howard Georgi, Quinn illuminated one path toward a GUT by demonstrating that such a unification might indeed be possible at high energies, at which the differences between the forces would blur and disappear. Three years later, with Roberto Peccei, she developed what we now know as the Peccei-Quinn theory, explaining why the strong force does not break CP (charge-parity) symmetry, providing another piece of the GUT puzzle. This work led to the prediction of the existence of a new fundamental particle called the axion, a leading candidate for dark matter. This apparently "missing matter" in the universe indirectly revealed by gravitational effects, but not yet directly observed, remains one of the major unresolved questions in physics and astronomy. Finally, Quinn explained the complementarity between quantum field theory in quarks and hadrons at high enough energies. Though none of these insights made the construction of a Grand Unified Theory immediately possible, they have proven to be significant steps along the path, inspiring and informing further promising theoretical and experimental directions in the decades since their publication. 
Quinn's contributions to science extend far beyond the boundaries of particle accelerators, laboratories, conferences, and the esoteric circles of theoretical physics. With a long-term interest in education and public science outreach, she has dedicated herself to the development of many educational resources in physics throughout her academic career. Since retiring from SLAC and Stanford, she has embraced a new role as a champion of primary science education on the national policy level. As a member and later chair of the Board on Science Education at the National Academy of Sciences, she led the development of the Framework for K-12 Science Education and the Next Generation Science Standards that were released in 2013 and have since been adopted by many states. 

Helen Quinn charted her path as one of the world's premier theoretical physicists and a scientist who profoundly influenced both her own scientific discipline as well as the science education of multitudes of students, some of whom will undoubtedly go on to become physics’s future trailblazers. Perhaps it will be due to this new generation of physicists that the grand dream of unification will finally be realized after all.

Information as of March 15, 2018