Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

How is it also a graviton particle as in string theory

  1. Feb 19, 2010 #1
    if gravity is a a sheet of space and time how is it also a graviton particle as in string theory
     
  2. jcsd
  3. Feb 19, 2010 #2

    jtbell

    User Avatar

    Staff: Mentor

    Re: gravitons

    Curved spacetime on the one hand and gravitons on the other hand, would be two alternative descriptions of gravity. This is similar to the way that classical electric and magnetic fields on the one hand, and quantum electrodynamics with photons on the other hand, are alternative descriptions of electromagnetism.

    Keep in mind that we do not (yet) have a generally accepted theory of quantum gravity (which would include gravitons), nor do we yet have any experimental observations which clearly require gravitons for their explanation. Gravitons are still pretty much a speculative concept. This is unlike quantum electrodynamics which has been tested extensively by experiments, and does explain experiments that classical electrodynamics does not.
     
  4. Feb 21, 2010 #3

    blechman

    User Avatar
    Science Advisor

    Re: gravitons

    One makes the connection between the two descriptions through a special kind of quantum state called a "Coherent State". In QED: coherent states of photons form the classical (or semi-classical to be technically correct) electromagnetic field. A similar thing happens with gravitons: a coherent state of gravitons generates a classical (curved) metric.
     
  5. Feb 22, 2010 #4
    Re: gravitons

    if possible can some one dumb up what he just said im only in high school and all these big words are confusing lol
     
  6. Feb 22, 2010 #5

    blechman

    User Avatar
    Science Advisor

    Re: gravitons

    not sure I can dumb it down very much. You should go with jtbell's post.

    coherent states are a way to reproduce classical physics behavior in a quantum mechanical system. don't worry about the details.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: How is it also a graviton particle as in string theory
  1. How do gravitons work? (Replies: 1)

Loading...