Description acceptable. Fourier modes correspond to an infinite “tower” of masses in one of these features. The implementation of these features with different members of mirror symmetric pairs counterintuitively yields equivalent results. The A·D·D model addresses the hierarchy problem with “large” instances of these features that comprise the “bulk” central to (*) brane (“brain”) cosmology. The dilaton is incorporated to explain gravitation in theories for which the volume of these features varies due to compactification, an operation whose limit behavior yields scalar fields. Kaluza–Klein theory explains electromagnetism with one of these features that is “curled up.” For 10 points, name these features of string theories that add to a quantity that equals one for time and three for space. ■END■
ANSWER: extra dimensions [accept answers that describe dimensions in addition to ones with standard physical interpretations, like space and time; accept dimensions of the bulk; prompt on dimensions; prompt on bulk by asking “what features of bulk motivate its implementation?”; prompt on compactified dimensions by asking “what property of the dimensions allows them to be compactified?”] (The lead-in refers to the Kaluza–Klein tower. Mirror symmetry is a property of pairs of Calabi–Yau manifolds.)
<Jeremy Cummings, Physics>
= Average correct buzz position