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

Susskind on supersymmetry vs. cosmological constant?

  1. Aug 7, 2015 #1
    In one book of Susskind I found the following claim and I wanted to ask for its basis.

    Susskind says that each kind of boson gives positive contribution to the cosmological constant (the lighter, the better). Each kind of fermion gives negative contribution to the cosmological constant. Thus, if supersymmetry holds, then the cosmological constant is zero.

    In our universe supersymmetry is slightly broken, so the cosmological constant is small but nonzero.

    Could you point be to a theory this thesis is based on? I guess this will be the string theory as it involves QFT and gravity.
  2. jcsd
  3. Aug 7, 2015 #2


    User Avatar
    Science Advisor

    Supersymmetric QFT and gravity together make a theory called supergravity, which can be formulated independently of string theory.
  4. Aug 7, 2015 #3


    User Avatar
    Gold Member

    Interesting. I had never heard that exact claim made before in that way.
  5. Aug 8, 2015 #4


    User Avatar
    Science Advisor

    It is based on a naive calculation of the quantum vacuum in supergravity with mattercouplings. For exact SUSY (where the masses of the superpartners are the same) the loopcontributions cancel.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook