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Questions about the traversable wormhole metric

  1. Sep 24, 2014 #1
    First of all, the metric I am referring to is this one:

    ds2= -c2dt2 + dl2 + (k2 + l2)(dᶿ2 + sin2(ᶿ)dø2)

    where k is the radius of the throat of the wormhole. (sorry for the small Greek letters)

    Now I have two questions about this solution to Einstein's equations:

    1. What does the coordinate l represent? All I know is that its domain is all real numbers and negative values of l apparently represents another universe.

    2. When this solution was derived, did the equations include the cosmological constant or was that just left out?
  2. jcsd
  3. Sep 24, 2014 #2


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    1. Looks like [itex]l[/itex] is the radial coordinate.

    2. In order for this to be a solution to Einstein's Equations, you need exotic matter that violates the energy conditions. There might be a cosmological constant but its contribution is swamped by that of the exotic matter.
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