Can a Single Particle Have Entropy?

Heisenberg and Schrödinger built two quantum theories that looked nothing alike but always agreed. Von Neumann's 1927 answer, the state vector in Hilbert space, explained why.

A second route to (17 − 6G)/240 that avoids elliptic integrals entirely, with each step checked and one error in the printed write-up corrected.

The word 'study' covers data collection, analysis and the paper itself. Here is how researchers can pin down which one they mean, and where each definition breaks.