FEYNMAN, RICHARD P. 3 PP AM ON FLUCTUATION THEORY, W/ HIS SIGNED COPY OF MATHEWS & WALKER, CA 1970

Autograph manuscript, 3 pp (8 1/2 x 11 in) in black ink on white typewriter paper watermarked "Mead Erasable", likely being lecture notes for a graduate class taught at Caltech on mathematical methods of physics, ca. 1970. WITH: MATHEWS & WALKER, Mathematical Methods of Physics. Menlo Park, Ca.: W. A. Benjamin, Inc., 1970. SIGNED "R.P. FEYNMAN" TO FLY-LEAF.

FEYNMAN ON FLUCTUATION THEORY & WHITE NOISE. The present highly detailed manuscript is very likely to be lecture notes for a course that Feynman taught on the mathematical methods of Physics at Caltech in the early 1970s. The Mathews & Walker text is well known even to this day and, with both Mathews and Walker being fellow faculty members at Caltech, it is not surprising that Feynman owned a copy. As the authors emphasize in the preface: “…this is a book about mathematics, for physicists.” Feynman no doubt heartily approved, given his predilections as a precocious teenager for “Calculus for the Practical Man,” borrowed from the local library back home in Far Rockaway (Gleick, pp. 32-36.) The analysis herein invokes Fourier methods, as applied to temporal signal processing, investigating the effects of noise & fluctuations, its filtering, power spectra, etc.; classic fare in such a grad course. See Mathews & Walker, sect. 4-2, which makes quick work of Fourier, but ends with a quick derivation, using such tools, of Heisenberg’s celebrated Uncertainty Relation.