弦论和M理论导论

Stringtheoryisoneofthemostexcitingandchallengingareasofmoderntheoreticalphysics.Itwasdevelopedinthelate1960sforthepurposeofde-scribingthestrongnuclearforce.Problemswereencounteredthatpreventedthisprogramfromattainingcompletesuccess.Inparticular，itwasrealizedthatthedpectrumofafundamentalstringcontainsanundesiredmasslessspin-twoparticle.Quantumchromodynamicseventuallyprovedtobethecorrecttheoryfordescribingthestrongforceandthepropertiesofhadrons，Newdoorsopenedforstringtheorywhenin1974itwasproposedtoidentifythemasslessspin-twoparticleinthestringsspectrumwiththegraviton，thequantumofgravitation.Stringtheorybecamethenthemostpromisingcan-didateforaquantumtheoryofgravityunifiedwiththeotherforcesandhasdevelopedintooneofthemostfascinatingthe6riesofhigh-energyphysics.