SCHIFF, LEONARD ISAAC

(b. Fall River, Massachusetts, 29 March 1915; d. Stanford, California 19 January 1971)

physics.

Schiff’s father, Edward, was a member of a Lithuanian family of rabbinical scholars, His mother, Mathilda Brodsky, also of Lithuanian descent, was a gifted pianist and composer. As a young man Schiff adopted an articulate Christian faith while staying close to his Jewish heritage: his funeral service included a striking reading, chosen by himself, from the New Testament Epistle to the Hebrews¹. A prodigy, especially in music and mathematics, he was already well versed in calculus upon entering Ohio State University in 1929, at the age of fourteen. There, influenced by L. H. Thomas, with whom he coauthored his first paper, he took up physics. He received his bachelor’s degree at eighteen and his master’s degree two years later. Despite his youth he was active in student affairs, becoming, among other things, captain of the university shooting team.

After obtaining a Ph.D. from MIT (1937) under, P.M. Morse for work on quantum scattering theory Schiff spent three years at Berkeley with J. Robert Oppenheimer before transferring to the University of Pennsylvania, where he soon shone as teacher, administrator (acting chairman of physics, 1942-1945), and resourceful applied mathematician. After publishing papers on liquid helium and meson theory in nuclei, he did war work on helium purity in blimps, on crystal detectors used in radar, and on automatic control in submarine steering. While at Los Alamos in 1945 he witnessed the “Trinity” bomb test and developed a deep concern for peace. In 1941 he married Frances Ballard; they had a daughter and a son.

In 1947 Schiff joined the small physics department at Stanford University. He became chairman a year later, holding that position through eighteen turbulent years that brought W. W. Hansen’s linear electron accelerator form factors, construction of the two-mile-long Stanford Linear Accelerator Center, and much else. He also established himself as one of the most powerful figures in the university, becoming chairman of the Advisory Board and in 1968, at the time of maximum student unrest, first chairman of the newly formed Faculty Senate. That with these activities and service on national committees he could maintain a research career is a tribute to Schiff’s rapidity of mind and intensely disciplined work habits. He died of a congenital heart defect, known to himself but hidden from colleagues, while on his way to a medical checkup prior to possible surgery.

Schiff’s main achievements were his textbook Quantum Mechanics (1949) and his researches on scattering theory and general relativity. His penchant was for rapid and relevant calculation rather than deep probing of concepts. His book tells his quality. Workmanlike, with none of the elegant profundity of Dirac’s treatise or the cluttered insights of Wigner’s, it was nevertheless a landmark text from which generations of graduate students learned how to do quantum mechanics. The second (1955), and still more the third (1968), edition carried useful improvements.

The Stanford Mark III linear accelerator, first operated in 1951, gave collimated pulses of fast electrons, with beam currents of 10¹¹-10¹² electrons/pulse and energies initially of 180 MeV, rising to 600 and then 900 MeV. Schiff was the ideal theoretical adviser, and in 1949, when the accelerator team was devastated by Hansen’s early death, he wrote a masterly report², still unpublished, on uses of the machine. One use concerned charge distributions in nuclei. Electrons energetic enough to have de Broglie wavelengths comparable with nuclear diameters could explore these distributions “much as lower energy electrons are now used to explore charge distributions in molecules and crystals by the technique of electron diffraction”. Appropriateenergies were 100 MeV or higher, and although some data at 15.7 MeV were obtained earlier at Illinois, the Stanford machine stood alone. In 1951 Hofstadter, a friend and co-worker of Schiff’s from the University of Pennsylvania, came to Stanford to lead a brilliant investigation establishing that nuclei, far from having sharp boundaries, comprise a uniform core surrounded by a region of progressively decreasing proton density. Parallel studies, also foreseen in Setoff-s report, included electron scattering from protons, neutrons, and deuterons.

In this field, theory and experiment went hand in hand. Much was done elsewhere, notably by L. R. B. Elton in London and H. Feshbach at MIT , but SchifT built the dominant theory group. With M. R. Rosenbluth, D. R. Yennie, D. G. Ravenhall, V, Z. Jankus, and others he established methods of exact phase-shift analysis, multipole expansion in inelastic scattering, dispersion corrections, the use of “charge” and “magnetic” form factors-to name but a few-basic to nuclear theory. For this achievement Schiff has hardly received due credit. Colleagues’ work never bore his name; only the warmth of acknowledgments tells his influence.

With Oppenheimer, Schiff in 1939 had learned general relativity to analyze a curious paradox about charge and rotation in electromagnetic theory. Not until 1958 did he return to a kindred topic: the mysterious absence of antimatter from the known universe. One proposal had been that matter and antimatter repel each other gravitationally. Schiff produced a startling counterargument. According to quantum electrodynamics, there are, even in ordinary matter, virtual electron-positron pairs associated with vacuum polarization. If matter also repels virtual antimatter, then gravitational and inertial mass will differ—by far more than experiment allows.

Next came experimental relativity. Of Einstein’s three “classical” tests, one, the red shift, was known to have very limited significance; Schiff, in a pedagogical article of 1960³, went on to challenge the famous starlight deflection test, Although general relativity gives twice the Newtonian deflection (as experiment requires), it does so because of a special relativistic effect that Einstein had overlooked. Angry refutations⁴ followed this claim, but so did many new ideas: “Schiff’s conjecture” about metric theories of gravity and the equivalence principle⁵, the Dicke and “parameterized post-Newtonian” frameworks for gravitational theories⁶ and—not least—the gyroscope experiment.

In November 19S9, a month after writing that article, Schiff, whose war work had made him familiar with gyroscope technology, began pondering the scientific applications of gyroscopes, After ideas about Mach’s principle and a clock experiment, he hit upon⁷ two phenomena in general relativity affecting gyroscopes in Earth orbit: a 6.6 arc-seconds/year geodetic precession, from the gyroscope’s motion through curved space-time, and, even more profound, a 0.043 arc-second/year frame-dragging precession from Earth’s rotation. Discussions with W. M. Fairbank and R. H. Cannon, joined in 1962 by the present writer, indicated that an experiment, though very difficult, might be feasible; in 1964 NASA began funding its development. Meanwhile, Schiff steadily widened his interests and at his death was in process of setting up a new group in relativistic astrophysics.

Schiff was a very good physicist, but he was greater as a human being than as a physicist. His touch appears in a colleague’s remark: “I always thought I had a special relationship with Schiff until I discovered that everyone else did too”⁸. The phrase “gentle strength” used by some is a misreading, however. His meticulous efficiency intimidated some people, and he could see through sham. He combined, most unusually, kindness, intellectual penetration, and moral force, and it was this last quality that made him so influential.

NOTES

1. Portions of Hebrews II: 1-32 (personal recollection).

2. “Survey of Possible Experiments with Linear Electron Accelerators”. [Stanford] Microwave Laboratory Report no. 102 (November 1949). Schiff, whose interest in accelerator design went back to 1938—see “On the Path of Ions in the Cyclotron”, in Physical Review, 54 (1938), 1114-1115—had earlier collaborated with Hansen in several reports on resonant cavity theory.

3. “On Experimental Tests of the General Theory of Relativity”, in American Journal of Physics, 28 (1960), 340-343. A similar claim had been advanced by W. Lenz in 1944: see Arnold Sommerfeld. Lectures on Theoretical Physics, III. Electro-dynamics (New York, 1952), 313-314, esp, 313.

4. The principal references are supplied by C. W. F. Everitt, “The Stanford Relativity Gyroscope Experiment” (see below), 598-599, 636.

5. The Schiff conjecture, as usually stated, is that any theory of gravitation consistent with special relativity and the equivalence principle must be a “metric” theory. Schiff propounded it, in rather different form, in a concise and sharply worded footnote to his American Journal of Physics article (p. 343), responding to a critique by Robert H. Dicke—American Journal of Physics, 28 (1960), 344-347—who argued that Einstein’s red shift formula does not automatically follow from equivalence and special relativity. For later treatments, see Clifford M. Will, Theory and Experiment in Gravitational Physics (Cambridge, 1981), 38-45, 50-53.

6. The “Dicke framework” was first spelled out in Appendix IV of Dicke’s Les Houches lectures. “Experimental Relativity”, in Cecile M. DeWitt and Bryce S. DeWttt, eds., Relativity, Groups and Topology (New York, 1964), 165-313. The PPN framework, first sketched by Arthur S. Eddington in The Mathematical Theory if Relativity (Cambridge, 1923), 105, was revived by H. P. Robertson and Schiff and then systematically developed from 1968 on by K. Nordtvedt. C. M. Will, and K. S. Thorne. Nordtvedt tells me that his ideas evolved in part from discussions with Schiff between 1961 and 1963.

7. “Possible New Experimental Test of General Relativity Theory”, in Physical Review Letters, 4 (1960), 215-217. For a conjectural retracing of Schiff’s path to the gyroscope experiment, see C. W. F. Everitt, “The Stanford Relativity Gyroscope Experiment” (below), 590-595.

8. Dr. G. Henry to the writer. For similar comments by others, see William M. Fairbank in Tributes (below).

BIBLIOGRAPHY

I. Original Works. Felix Bloch’s memoir (see below) lists 2 books, 91 research papers, and 58 other articles, reviews, or conference reports. Quantum Mechanics appeared in three editions (New York, 1949, 1955, 1968): a fourth, with A. L. Fetter, is in preparation. The first edition was translated into Italian—Meccanica quantistica, L. Radicati di Brozolo, trans. (Turin, 1951)—the second, into Japanese (2 vols., Kyoto, 1957-1958) and Russian (Moscow, 1959). Nucleon Structure (Stanford. Calif., 1964), edited with Robert Hofstadter, is the proceedings of the International Conference on Nucleon Structure held at Stanford University, 24-27 June 1963.

Schiff’s scientific and administrative papers are in the Stanford University archives; some personal material remains in Mrs. Schiff’s possession.

II. Secondary Literature. There is an obituary by Felix Bloch and J. D. Walecka in Physics Today, 24 (July 1971), 54-55; and a memoir by Bloch in Biographical Memoirs. National Academy of Sciences, 54 (1983), 301–323. The latter’s version of the history of the Stanford physics department should be taken cum grano salis; a partial corrective is P. Galison. B, Hevly, and R. Lowen, “Controlling the Monster: Stanford and the Growth of Physics Research 1935-1962”, in P. Galison and B. Hevly, eds., Big Science: The Growth of Large Scale Research (Stanford. Calif., in preparation). Personal impressions of Schiff by R. M. Brown, F. Bloch, R. Hofstadter, W. Stegner, B. D. Napier, and W. M. Fairbank appear in Tributes to Leonard Isaac Schiff 1915-1971 (produced at Stanford in 1971 without editorial ascription or publication details). A sharp vignette by R. H. Cannon is in J. Fincher, “The Methusaleh Project”, Air & Space, 1 (February/March, 1987), 96-98.

On nuclear scattering, see the reprint collection edited by Robert Hofstadter. Electron Scattering and Nuclear and Nucleon Structure (New York, 1963), which omits Schiff’s paper “Interpretation of Electron Scattering Experiments”, in Physical Review, 92 (1953), 988-993, published back to back with Hofstadter, Fechter, and Mclntyre’s first major experimental paper. Lewis R. B. Elton. Nuclear Sizes (London, 1961) may also be consulted.

On gravitational theory, see C. W. F. Everitt, “The Stanford Relativity Gyroscope Experiment (A): History and Overview”, in J. D. Fairbank. B. S. Deaver, C. W. F. Everitt, and P. Michelson, eds., Near Zero: New Frontiers of Physics (New York, 1988), 587-639.

C. W. F. Everitt