Joseph Sucher

Joseph (Joe) Sucher, a theoretical physicist whose whole 41-year career was at the physics department of the University of Maryland in College Park, died on 18 October 2019. Joe was wise, warm, caring, supportive, outgoing, and enjoyable, especially for his students. Known for his sparkling wit, his ability to write a poem for any departmental function, and his mastery of the bon mot, Joe had a phenomenal memory. He told many past and “present” anecdotes about physics and physicists.

Joseph Sucher and his twin sister were born on 10 September 1930 in Vienna. He had two older siblings. Joe’s father had a PhD in Semitic languages, but, being Jewish, could not get an academic job. Instead he helped Joe’s mother in her textile store. Joe, being Jewish, was forced to attend a “Jewish” school.

On 13 March 1938 Hitler’s Nazi army took over Austria. Joe remembers hearing Hitler speak. A Nazi officer once verbally attacked Joe as a “Jewish Pig!” Once Joe and his father witnessed the Nazis arresting people. Luckily, they let him and his father go. Later, the Nazis “requisitioned” his mother’s store.

Showing admirable and extreme foresight, the family began arrangements to flee Hitler’s Austria. In August 1938 his father traveled to Luxembourg. In December 1938 Joe’s mother and the four children obtained visas to exit Germany ostensibly to “visit” Joe’s father. Joe was 8. They stayed in Luxembourg for nearly two years, waiting to get US visas. Joe had no schooling. Joe’s family at last got their American visas and went on a dangerous and difficult trip through France and Spain to Portugal. They immigrated to the US in June 1941, to join distant family in Milwaukee.

Joe’s immediate family had escaped. The Nazis murdered some of his extended family.

The family moved to Brooklyn. In 1952 Joe graduated from Brooklyn College, summa cum laude, with honors in mathematics and physics. In 1957 he received a physics PhD from Columbia University. His thesis was on the quantum electrodynamics of the helium atom, under Henry Foley as adviser. He was awarded the Higgins Prize.

When John Toll was hired to build up the physics department at Maryland, he hired Joe straight out of graduate school. For 41 years until 1998, Joe contributed greatly to both research and teaching. He advised 20 PhD students. He was a devoted educator.

Honors included a Guggenheim Fellowship (1968) and UMD Distinguished Scholar–Teacher (1989). In 1990 Toll wrote, “All of his work is characterized by an ability to strike through a morass of material and to explain what’s really going on, in ways that clarify and stimulate the work of many others.”

Joe’s work in theoretical physics spanned the areas of atomic and high-energy elementary particle physics. Joe published exactly 100 refereed papers, many invited papers, summer school lectures, review articles, and book contributions.

Joe is best known for work on the relativistic theory of many-electron atoms, the quantum theory of long-range forces, the foundations of relativistic quantum theory, the Gellman-Low-Sucher level-shift formula, the no-pair Hamiltonian for many-electron atoms, the Levy-Sucher identity, the Dirac–Sucher equation, and the Feinberg–Sucher formula for the long-range force between neutral atoms.

The 1960 work by Day, Snow, and Sucher, “High orbital S-state capture of π⁻ mesons by protons,” was very important for understanding kaon physics. It brought a great deal of attention to them, the physics department, and Maryland.

Some important works: Joe gave a theoretical analysis of relativistic invariance and the square-root Klein–Gordon equation; studied the foundations of the relativistic theory of many-electron atoms; discussed confinement in relativistic potential models; presented a general analysis “Ground state energy of any atom"; and gave a general discussion, “What is the force between electrons?”

Joe had a series of collaborations with Gary Feinberg. They studied long-range interactions of neutral particles and constructed a general theory of van der Waals interactions; studied long-range forces from neutrino-pair exchange; and studied the strong van der Waals force between hadrons.

With N. D. Son, Joe compared the treatment of relativistic two-body bound states using a relativistic two-body Hamiltonian, with that using the Bethe–Salpeter equation. With C. H. Woo, he studied the light-cone dominance of the asymptotic behavior of vertex functions and scattering amplitudes. Joe, together with Feinberg and C. K. Au, wrote “The dispersion theory of dispersion forces.” Joe, with Greenberg and Nussinov, studied a quark model relationship for kaon charge radii.

Truly, Joe will be sorely missed.