In string theory, the strings vibrate due to the inherent nature of their dynamics. The vibrations of the strings correspond to different energy levels and modes of excitation, which in turn give rise to different particles and their properties.
According to string theory, the fundamental constituents of the universe are not point-like particles but tiny, one-dimensional strings. These strings have a tension, similar to a guitar string, that determines their behavior. The tension of the string governs how tightly it is stretched, influencing the vibrational patterns it can exhibit.
The different vibrational modes of the string correspond to different energy states or harmonics. Just as a guitar string can vibrate in different patterns (e.g., plucking it at different points or with different strengths), the string in string theory can vibrate in various ways. Each vibrational mode represents a specific energy and angular momentum associated with the string's oscillations.
The vibrational modes of the string correspond to different types of particles in the universe. For example, a string vibrating in one mode might correspond to a photon (the particle of light), while a different vibrational mode could represent an electron or a quark.
The specific vibrational patterns and modes of the strings are determined by the geometry of the extra dimensions in which the strings propagate. The interaction between the strings and the geometry of the extra dimensions gives rise to the diverse range of particles and their properties that we observe in our universe.
It's important to note that the precise details of string theory's vibrational modes and their connection to particles are complex and highly mathematical. The theory describes these relationships through mathematical equations and calculations that involve the geometry of the extra dimensions and the dynamics of the strings.