Unified field theory classical field theory and, two years later, that of Theodor Kaluza, who extended General Relativity to five dimensions. Continuing in this latter direction, Oscar Klein proposed in 1926 that the fourth spatial dimension be curled up into a small, unobserved circle. In Kaluza–Klein theory, the gravitational curvature of the extra spatial direction behaves as an additional force similar to electromagnetism. These and other models of electromagnetism and gravity were pursued by Albert Einstein in his attempts at a classical unified field theory. By 1930 Einstein had already considered the Einstein–Maxwell–Dirac System [Dongen]. This system is (heuristically) the super-classical [Varadarajan] limit
Unified field observed in Igor Stravinsky's Russian period, such as in "Les Noces", derived from his use of folk melodies as generating material and influenced by shorter pieces by Claude Debussy, such as "Voiles", and Modest Mussorgsky. In Béla Bartók's Bagatelles, and several of Alfredo Casella's "Nine Piano Pieces" such as No. 4 'In Modo Burlesco' the close intervallic relationship between motive and chord creates or justifies the great harmonic dissonance. Unified field In music, unified field is the 'unity of musical space' created by the free use of melodic material as harmonic material and vice versa. The technique is most associated