 In bosonic string theory, the attempt is to compute the possible energy levels of a string, in particular the lowest energy level.Speaking informally, each harmonic of the string can be viewed as a collection of "D" − 2 independent quantum harmonic oscillators, one for each transverse direction, where "D" is the dimension of spacetime.If the fundamental oscillation frequency is "ω" then the energy in an oscillator contributing to the "n"th harmonic is .