April 2020 Issue,
Volume 88, No. 4
The Persian Immortals: A classical case of self-organization
We present an example from classical history that perfectly illustrates the concept of a self-organizing system, namely, the “Persian Immortals” described by Herodotus. Their name refers to the fact that their number was always kept constant (at 10 000) by instantly substituting every warrior who fell during a battle. One evident advantage of this was to undermine the morale of the enemy troops. Here, we focus on a second major benefit, namely, that the Immortals—thanks to the replacement tactics—were actually becoming a stronger unit in the course of the battle. Modeling the substitution of the fallen ones by a plausible set of replacement rules, and using Order Statistics to analyze the evolution of the unit's fitness, we show that the distribution of fighting skills will ripen to a robust and favorable equilibrium state.
PAPERS
The Persian Immortals: A classical case of self-organization by Giorgos Kanellopoulos, Dimitrios Razis and Ko van der Weele. DOI: 10.1119/10.0000834
Seven formulations of the kinematics of special relativity by W. N. Mathews Jr. DOI: 10.1119/10.0000851
Two-penny physics: Teaching 2D linear momentum conservation by Lorenzo Galante and Ivan Gnesi. DOI: 10.1119/10.0000518
Angular momentum in the fractional quantum Hall effect by S. J. van Enk. DOI: 10.1119/10.0000831
The motion of a conical pendulum in a rotating frame: The study of the paths, determination of oscillation periods, and the Bravais pendulum by José A. Giacometti. DOI: 10.1119/10.0000374
Incorporating the Stern-Gerlach delayed-choice quantum eraser into the undergraduate quantum mechanics curriculum by William F. Courtney, Lucas B. Vieira, Paul S. Julienne and James K. Freericks. DOI: 10.1119/10.0000519
Geodesy on surfaces of revolution: A wormhole application by Lorenzo Gallerani Resca and Nicholas A. Mecholsky. DOI: 10.1119/10.0000464
Single photon beat note in an acousto-optic modulator-based interferometer by Renaud Mathevet, Benoit Chalopin and Sébastien Massenot. DOI: 10.1119/10.0000299
Stirling engine operating at low temperature difference by Alejandro Romanelli. DOI: 10.1119/10.0000832
The negative flow of probabilityby Anthony Allan D. Villanueva. DOI: 10.1119/10.0000856
BACK OF THE ENVELOPE
A zeroth power is often a logarithm yearning to be free by Sanjoy Mahajan. DOI: 10.1119/10.0000841
NOTES AND DISCUSSIONS
Erratum: “Reliable determination of contact angle from the height and volume of sessile drops” [Am. J. Phys. 87(1), 28–32 (2019)] by F. Behroozi and P. S. Behroozi. DOI: 10.1119/10.0000387
BOOK REVIEWS
Chaos and Dynamical Systems by John L. Bohn. DOI: 10.1119/10.0000678
BOOKS RECEIVED
American Journal of Physics 88, 256 (2020); https://doi.org/10.1119/10.0000638
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