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Imaginary numbers and Imaginary Time

  1. Oct 29, 2009 #1
    Imaginary numbers are a lot less mysterious than they sound. They are the result from trying to take the square root of a negative number. They are called “imaginary” because they don’t exist in the normal number system, normally you can’t take the square root of a negative number because the product of two negatives is always positive. Using imaginary numbers allows physicists to plot time like is was just another dimension of space.

  2. jcsd
  3. Oct 29, 2009 #2


    Staff: Mentor

    Physicists don't need imaginary numbers to plot time. Each point in space has three real coordinates: (x, y, z). If you also want to indicate the time relative to some specific time, you can use a fourth, real coordinate, t: (x, y, z, t).
  4. Oct 29, 2009 #3
    I don't think that they are mysterious at all, it's just a field defined differently from an ordinary Real number field
  5. Oct 29, 2009 #4
    There are two very important aspects of imaginary time that are not mentioned. 1) imaginary time corresponds to equilibrium thermodynamics: if a system is held at a temperature T, one can set time= i /( k_B T ) where i is the imaginary number 2) Making this transformation converts the Schroedinger equation , which has wave solutions into a diffusion-like equation. An additional 'clue' that an imaginary time axis is relevant to real physics lies in relativistic formula for "distance" =√∆d2 - ∆t2 . If the universe is actually built on imaginary time τ ≈ i•t, then that peculiar '-' sign is there because we are [for whatever reason] using t, where squaring iτ=-t2.
  6. Oct 29, 2009 #5
    http://www.universe-review.ca/" [Broken]
    Last edited by a moderator: May 4, 2017
  7. Nov 12, 2009 #6
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