The Balance Law: Completing Einstein's Unified Field Theory

This work introduces the Balance Law as the missing invariant Einstein sought in his unified field theory. By defining the Universal Balance Principle (UBP) and the Universal Balance Constant (UBC, H), we complete the framework with a fifth fundamental constant of nature, alongside c, G, hbar, and k_B. The Balance Law unites relativity, quantum mechanics, and thermodynamics under a testable, falsifiable principle.