A ‘Freak’ and a Standard Physicist, Separate Yet Together, on the Road to Quantum Mechanics

For more than three decades, the author and Song Hee-sung shared offices, lunches and daily life at Seoul National University, despite following sharply different paths in physics and beyond.

The author describes himself as having pursued a freer route outside the mainstream of physics, while Song remained a “standard physicist” who stayed firmly within the discipline’s established path. Both studied theoretical physics and entered Seoul National University a year apart, but their academic interests diverged. The author worked in condensed matter physics and explored social issues and public activities. Song devoted himself almost entirely to physics and education.

That focus did not keep Song away from institutional responsibilities. He served as a department chair, an associate dean, the head of the physics department and director of the university’s Institute for Theoretical Physics. Outside the university, he led the Korean Physical Society and the Korean Federation of Science and Technology Societies. The author presents these roles as evidence of Song’s steady contribution to the university and the wider academic community.

At a memorial gathering, the author offered one word to describe Song: “rice.” Song had been his lunch companion for more than 30 years, but the metaphor also referred to education. If the author supplied distinctive side dishes to students, he wrote, Song provided the staple food.

That role was embodied in Song’s book Quantum Mechanics, first published in 1984 and revised in 2009. The roughly 700-page volume, packed with formulas, became what the author calls the first serious Korean-language textbook in the field. Students nicknamed it “Song Quantum,” and it has remained in use for more than 40 years. The author portrays it as a demanding but reliable route through the subject, a standard quantum mechanics text that aspiring professional physicists had to master.

His own approach differs. He prefers books that leave readers with images and intuitive understanding, rather than only mathematical completeness. In 2022, he published How Can We Understand Quantum Mechanics?, a shorter volume with about 300 pages and far fewer formulas. He hopes readers will find that the book allows them to understand quantum mechanics without becoming professional physicists. Despite their differences, he and Song remained comfortable together, often taking light walks around Gwanak Mountain after lunch.