arXiv subjects

Freeman J. Dyson

Publications and source records attributed to Freeman J. Dyson.

3 recordsLinked to original sources

arXiv2023

Gravitational Machines

A gravitational machine is defined as an arrangement of gravitating masses from which useful energy can be extracted. It is shown that such machines may exist if the masses are of normal astronomical size. A simple example of a gravitational machine, consisting of a double star with smaller masses orbiting around it, is described. It is shown that an efficient gravitational machine will also be an emitter of gravitational radiation. The emitted radiation sets a limit on the possible performance of gravitational machines, and also provides us with a possible means for detecting such machines if they exist.

gr-qc↗

arXiv2020

SanD primes and numbers

We define S(um)anD(ifference) numbers as ordered pairs $(m,\, m+Δ)$ such that the digital-sum $DS(m(m+Δ))=Δ.$ We consider both the decimal and the binary case. If both $m$ and $m+Δ$ are prime numbers, we refer to SanD {\em primes}. We show that the number of (decimal-based) SanD numbers less than $x$ grows as $c1\cdot x,$ where $c1 = 2/3,$ while the number of SanD primes less than $x$ grows as $c2\cdot x/\log^2{x},$ where $c2 = 3/4.$ Due to the quasi-fractal nature of the digital-sum function, convergence is both slow and erratic compared to twin primes, which, apart from the constant, have the same leading asymptotics.

math.CA↗

arXiv2006

1951 Lectures on Advanced Quantum Mechanics Second Edition

The legendary 1951 Dyson Lectures on Advanced Quantum Mechanics are finally LaTeXed, with thorough annotations and an index as an added bonus. See the Typist's Afterward preceding the backmatter for an explanation of this new version, and for the historical context see the website: http://hrst.mit.edu/hrs/renormalization/dyson51-intro/ as well as the author's website at the Princeton Institute for Advanced Study: http://www.sns.ias.edu/~dyson/

quant-ph↗