Some simple questions in theoretical physics

Discussion in 'Physics & Math' started by jnc1110, May 29, 2009.

  1. jnc1110 Registered Senior Member

    Messages:
    52
    First and foremost, let me say that I am no physics major. I'm just an undergrad on summer vacation with a lot of thinking time on my hands. This topic may be irrelevant to conventional physics but I feel it can be explained through theoretical physics.


    If positive energy (matter) is derrived from negative energy (space), then where does spatia originate? Under what conditions can you get something from nothing? With relgion and the Big Bang Theory aside, how can the evolution of matter be explained?

    Any insights would be fantastic!!
     
  2. Google AdSense Guest Advertisement



    to hide all adverts.
  3. James R Just this guy, you know? Staff Member

    Messages:
    39,421
    Where did you get the idea that space is a form of negative energy? Space is not a substance or a type of energy.

    Have you heard of quantum fluctuations of the vacuum? What happens there is that in "empty" space the universe can spontaneously create pairs of particles by "borrowing" energy from nothing for a (very) short period of time (determined by Heisenberg's uncertainty principle). That energy is "paid back" when the particle annihilate each other again, returning the net energy of the system to zero.

    Is this the kind of thing you want to know about?
     
  4. Google AdSense Guest Advertisement



    to hide all adverts.
  5. Acitnoids Registered Senior Member

    Messages:
    704
    Didn't Stephen Hawking use this mechanism to show that a black hole will evaporate over time threw Hawking radiation? This means information can still escape the event horizon by way of heat (black body) or am I confusing two different things?
     
  6. Google AdSense Guest Advertisement



    to hide all adverts.
  7. James R Just this guy, you know? Staff Member

    Messages:
    39,421
    You're right, Acitnoids.
     
  8. prometheus viva voce! Registered Senior Member

    Messages:
    2,045
    Not quite. If Hawking radiation is purely thermal it leads to the black hole information loss paradox. Suppose we have a pure quantum state that collapses to form a black hole, which then evaporates via the Hawking process. The final state will be a thermal superposition of pure states or a mixed state which is not allowed since information is lost between initial and final configurations.

    Resolutions have been proposed that state that the Hawking radiation is not exactly black body but contains quantum corrections that allows the information that we thought was lost to escape from the black hole. However, most physicists still regard this as an open problem.
     
  9. James R Just this guy, you know? Staff Member

    Messages:
    39,421
    prometheus:

    What happened after Hawking's big announcement that he had solved the information problem? Did it turn out that he hasn't solved it, then?
     
  10. EndLightEnd This too shall pass. Registered Senior Member

    Messages:
    1,301

    Alan Watts on nothingness...
    http://www.youtube.com/watch?v=dLrMVous0Ac
     
  11. prometheus viva voce! Registered Senior Member

    Messages:
    2,045
    Hawking's solution to the information loss paradox only applies to asymptotically AdS spaces where you can relate the black hole to a thermal CFT. It doesn't work directly for black holes in flat space because you can't relate the black hole system to a field theory in the same way. At least, we don't know how to.
     
  12. Acitnoids Registered Senior Member

    Messages:
    704
    So then what you are saying is that the black hole will still evaporate yet only some of the original information will escape. Most of it would be "lost". As for posts 5 & 8. Could the information paradox be intetpreted as a flaw in the concept of a pure quantum state due to the incompatibility between black holes and field theory? Lastly, isn't it Hawkings equations that laid to rest any concern that the LHC will produce long lived black holes capable of destroying the earth?
     

Share This Page