The Einstein-Varicak Correspondence on Relativistic Rigid Rotation

The historical significance of the problem of relativistic rigid rotation is reviewed in light of recently published correspondence between Einstein and the mathematician Vladimir Varicak from the years 1909 to 1913.

💡 Research Summary

The paper presents a comprehensive historical and technical study of the correspondence between Albert Einstein and the mathematician Vladimir Varičak from 1909 to 1913, focusing on the problem of relativistic rigid rotation. It begins by outlining the classical notion of a perfectly rigid body and the challenges that special relativity posed for such a concept, especially when a body undergoes uniform rotation. The authors then trace how Einstein first raised the issue in a 1909 letter, asking whether a “rigid” rotating disc could be reconciled with the constancy of the speed of light and the relativity of simultaneity.

Varičak responded by introducing a Riemannian metric for a rotating reference frame. Using cylindrical coordinates ((r,\phi,z)) and an angular velocity (\omega), he wrote the line element as

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