Herch Moysés Nussenzveig (1933–2022): The Architect of Brazilian Physics and the Theory of the Rainbow
Herch Moysés Nussenzveig was a titan of Brazilian science, a world-renowned theoretical physicist whose work bridged the gap between complex mathematical abstractions and the everyday beauty of natural phenomena. Best known internationally for his definitive explanation of the rainbow and the "glory" effect, he was also a pivotal figure in the institutional development of science in Brazil.
1. Biography: A Life of Science and Principles
Herch Moysés Nussenzveig was born on January 16, 1933, in São Paulo, Brazil, to Jewish immigrants of Polish and Russian descent. His intellectual journey began at the University of São Paulo (USP), where he completed his undergraduate degree in 1954 and his PhD in 1957. He studied under the guidance of Mario Schönberg, one of Brazil’s most influential theoretical physicists.
Nussenzveig’s career was marked by both international excellence and domestic struggle. During the 1960s, a period of political upheaval in Brazil, he held research positions at the Eindhoven University of Technology, the University of Zurich, and the University of Birmingham. In 1964, following the military coup in Brazil, he moved to the United States, joining the University of Rochester—a global hub for optics.
He returned to Brazil in 1968 to lead the Physics Department at USP, but the intensification of the military dictatorship (marked by the Institutional Act No. 5) forced him into a second period of exile. He spent several years as a professor at the University of Rochester and later at the University of California, Santa Barbara. He finally returned to Brazil permanently in 1975, joining the Pontifical Catholic University of Rio de Janeiro (PUC-Rio) and later the Federal University of Rio de Janeiro (UFRJ), where he remained an Emeritus Professor until his death on November 5, 2022.
2. Major Contributions: From Causality to the Rainbow
Nussenzveig’s research focused primarily on mathematical physics and optics, specifically how light and matter interact.
- Theory of the Rainbow and the Glory: Nussenzveig provided the most complete mathematical description of the rainbow. While the basic geometry was understood since Descartes and Newton, the subtle "fringes" (supernumerary bows) and the "glory" (the halo seen around a shadow on a cloud) required sophisticated wave theory. He applied Complex Angular Momentum (CAM) theory—a technique borrowed from particle physics—to Mie scattering. This allowed him to describe the "tunneling" of light waves that produces these atmospheric effects.
- Causality and Dispersion Relations: He was a pioneer in using the principle of causality (the cause must precede the effect) to derive mathematical constraints on how waves travel through media. This work is fundamental to understanding the refractive index and how energy is absorbed by materials.
- Semiclassical Scattering: He developed methods to bridge the gap between classical "ray" optics and quantum "wave" mechanics, providing tools to calculate how particles and waves scatter in high-energy environments.
3. Notable Publications
Nussenzveig was a prolific writer, authoring over 100 scientific papers and several seminal books.
- "The Theory of the Rainbow" (1977): Published in Scientific American, this article remains one of the most cited and accessible explanations of the physics of atmospheric optics.
- Causality and Dispersion Relations (1972): A foundational academic monograph that remains a standard reference in the field of wave propagation.
- Curso de Física Básica (4 Volumes): Perhaps his greatest legacy in Brazil. These textbooks (published between 1981 and 1998) revolutionized how physics is taught in Portuguese-speaking countries. Known simply as "The Moysés," they are famous for their rigor, clarity, and emphasis on conceptual understanding over rote memorization.
- Diffraction Effects in Semiclassical Scattering (1992): A comprehensive book detailing his work on the intersection of classical and quantum wave phenomena.
4. Awards & Recognition
Nussenzveig’s contributions earned him the highest honors in the scientific community:
- Max Born Award (1986): Awarded by the Optical Society of America (OSA) for his distinguished contributions to physical optics.
- Álvaro Alberto Award (1995): Brazil’s most prestigious prize for science and technology.
- Grand Cross of the National Order of Scientific Merit: One of Brazil's highest civilian honors.
- President of the Brazilian Physical Society (SBF): He served from 1981 to 1983, playing a key role in the society's growth.
- Member of the Brazilian Academy of Sciences (ABC) and the World Academy of Sciences (TWAS).
5. Impact & Legacy
Nussenzveig’s impact is two-fold: scientific and educational.
Scientifically, his work on the "glory" and the "rainbow" solved problems that had puzzled physicists for centuries. His application of Regge pole theory to optics provided a template for solving scattering problems in other fields, including acoustics and nuclear physics.
Educationally, he is the "father" of modern Brazilian physics education. His Curso de Física Básica series challenged students to think like researchers. He was a fierce advocate for science funding and autonomy, often clashing with government officials to protect the integrity of Brazilian research institutions. He was instrumental in establishing the National Institute of Science and Technology for Quantum Information.
6. Collaborations
Nussenzveig maintained deep ties with the international physics community.
- The Rochester Group: He collaborated closely with Leonard Mandel and Emil Wolf, two of the founders of modern quantum optics.
- Students: He mentored generations of Brazilian physicists who went on to lead departments across South America and the US. His influence ensured that the "Brazilian school" of optics remained world-class.
- Policy: He worked alongside other Brazilian scientific luminaries like Ennio Candotti and José Goldemberg to navigate the challenges of doing science under a military regime.
7. Lesser-Known Facts
- Scientific Dynasty: Intelligence runs in the family. His daughters are also highly distinguished scientists: Helena Nussenzveig Lopes is a prominent mathematician, and Micheline Nussenzveig is a noted physicist.
- The "Nuclear" Critic: In the 1970s, Nussenzveig was a vocal critic of the nuclear agreement between Brazil and West Germany. He argued that the deal was focused on "turnkey" technology rather than developing local scientific expertise, a stance that required significant courage during the dictatorship.
- Art and Science: He was known for his deep appreciation of the arts and often used the rainbow not just as a mathematical problem, but as a bridge to discuss the aesthetic beauty of the natural world, citing poets and painters in his lectures.
- A "Hard" Teacher: Among Brazilian engineering and physics students, "passing Moysés" (completing a course using his textbooks) is considered a rite of passage and a badge of honor due to the high level of mathematical rigor he demanded.
Herch Moysés Nussenzveig remains a symbol of scientific excellence and resilience. He demonstrated that even in developing nations and under political duress, one can produce work that illuminates the most fundamental mysteries of the light that surrounds us.