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nLab > Latest Changes: T-duality

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  1.  
    • CommentRowNumber1.
    • CommentAuthorUrs
    • CommentTimeJun 11th 2010

    Added to T-duality a section with the discussion of the usual path-integral heuristics for why the two sigma-models on T-dual backgrounds yield equivalent quantum field theories.

  2. Dear Urs,

    the path integral heuristics behind path-integral sigma-models T-duality should actually be simpler (at least at the level of the naive idea). Namely, everything boils down to saying that the 2-torus obtained by opposite sides identification of [0,1]×[0,T][0,1]\times [0,T] and the one obtained by opposite sides identification of [0,1]×[0,1/T][0,1]\times [0,1/T] (both with the standard flat metric obtained by restriction from ℝ 2\mathbb{R}^2) are conformally equivalent.

    A way of seeing this is to recall that up to conformal equivalence a 2-torus can be seen as a parallelogram in ℂ=ℝ 2\mathbb{C}=\mathbb{R}^2 with a vertex in 00, a vertex in 11 and the other vertex in τ∈ℍ\tau\in\mathbb{H}, where ℍ\mathbb{H} denotes the upper half-plane. The torus of parameter τ\tau and the one of parameter τ′\tau' are conformally equivalent iff

    τ′=aτ+bcτ+d \tau'=\frac{a\tau+b}{c\tau+d}

    with

    (a b c d) \left( \array{ a&b\\ c&d }\right)

    in SL(2;ℤ)SL(2;\mathbb{Z}). The two parameters iTi T and i/Ti/T are related by the matrix

    S=(0 −1 1 0) S=\left( \array{ 0&-1\\ 1&0 }\right)
    • CommentRowNumber3.
    • CommentAuthorUrs
    • CommentTimeJun 11th 2010

    True, but I do not quite see how you’d derive T-duality of the target space this way.

    Also, one point of the computation I posted is that it also applies to the open string and shows the action of T-duality on D-branes.

    • CommentRowNumber4.
    • CommentAuthordomenico_fiorenza
    • CommentTimeJun 11th 2010
    • (edited Jun 11th 2010)

    Right, I misunderstood what you were referring to. now I see that what I wrote could have something to do with what you were saying, but at the moment I could not say exactly what.. :)

    • CommentRowNumber5.
    • CommentAuthorUrs
    • CommentTimeJun 11th 2010
    • (edited Jun 11th 2010)

    I think you are certainly right that the basic mechanism underlying T-duality is at least morally that of the SS-transformation on a torus. But I don’t quite see how one can upgrade this observation to a proof that two T-dual backgrounds give equivalent sigma-model QFTs. Possibly there is a way, though.

    • CommentRowNumber6.
    • CommentAuthorDavid_Corfield
    • CommentTimeFeb 14th 2012

    Correcting some typos at T-duality, I don’t know how to fix

    A quick way to get an indication for this is to notice that the center-of-mass energy of the string in such a circle-bundle background is In terms of the worldsheet theory.

    • CommentRowNumber7.
    • CommentAuthorUrs
    • CommentTimeFeb 14th 2012

    Thanks for catching this. Not sure what happened there. I have changed the sentence to

    A quick way to get an indication for this is to consider the center-of-mass energy of the string in such a circle-bundle background.

    • CommentRowNumber8.
    • CommentAuthorUrs
    • CommentTimeJan 4th 2019

    added pointer to today’s

    diff, v45, current

    • CommentRowNumber9.
    • CommentAuthorDavid_Corfield
    • CommentTimeApr 9th 2019

    Added a new reference

    • Mark Bugden, A Tour of T-duality: Geometric and Topological Aspects of T-dualities, (arXiv:1904.03583)

    diff, v46, current

    • CommentRowNumber10.
    • CommentAuthorUrs
    • CommentTimeAug 8th 2022
    • (edited Aug 8th 2022)

    added pointer to:

    diff, v54, current

  11. adding reference

    • Hyungrok Kim, Christian Saemann, Non-Geometric T-Duality as Higher Groupoid Bundles with Connections (arXiv:2204.01783)

    Anonymous

    diff, v56, current

    • CommentRowNumber12.
    • CommentAuthorUrs
    • CommentTimeSep 23rd 2024
    • (edited Sep 23rd 2024)

    added pointer to today’s preprint (replacement)

    and grouped together all the reference on super-space T-duality

    diff, v61, current

    • CommentRowNumber13.
    • CommentAuthorUrs
    • CommentTimeOct 1st 2024

    A propos, we now keep here a streamlined account of the computations of super-space T-duality (for anyone who found the original article hard to read).

    • CommentRowNumber14.
    • CommentAuthorUrs
    • CommentTimeOct 15th 2024

    … and here is now a further expanded discussion.

    • CommentRowNumber15.
    • CommentAuthorDavid_Corfield
    • CommentTimeOct 15th 2024

    Just to note that you have two articles as [GSS24d] in the references.

    • CommentRowNumber16.
    • CommentAuthorUrs
    • CommentTimeOct 16th 2024

    Thanks for spotting. Fixed now.

    • CommentRowNumber17.
    • CommentAuthorDavid_Corfield
    • CommentTimeOct 16th 2024

    dimentions; homotpy; Poinca&eacute

    and

    The prefactors of 1/2 in (22) is not fixed

    should be ’prefactor’.

    Does the ’M theory from the superpoint’ account carry over to this setting?

    • CommentRowNumber18.
    • CommentAuthorUrs
    • CommentTimeOct 17th 2024

    Thanks for catching typos. Fixed now.

    The discussion in "M-theory from the superpoint" is on the same general theme as the super-space T-duality, in that both are concerned with the typical super-tangent spaces (the Kleinian local model space) only, and yet discover much of the general expected structure.

    • CommentRowNumber19.
    • CommentAuthorperezl.alonso
    • CommentTimeFeb 21st 2025

    The IIA dual in Definition 3.42 in 2411.10260, is that supposed to be the IIA* string theory in signature 1+9 mentioned in hep-th/9807127?

    • CommentRowNumber20.
    • CommentAuthorUrs
    • CommentTimeFeb 21st 2025

    That’s a good point. Maybe we should use that notation.

    • CommentRowNumber21.
    • CommentAuthorperezl.alonso
    • CommentTimeFeb 21st 2025

    I see. And to obtain such a dual, was it necessary to go all the way to the superpoint, or does one obtain the same by going to ℝ 1,1\mathbb{R}^{1,1}? If the latter, can one obtain the 5+5 IIA one by going to ℝ 5,1\mathbb{R}^{5,1} (all super Minkowski with appropriate supercharges, of course)?

    • CommentRowNumber22.
    • CommentAuthorUrs
    • CommentTimeFeb 21st 2025

    The observation of the article is diagram (10) on p 9, showing that there is a curious kind of lift of T-duality to M-theory for the case of T-duality along all 1+9 spacetime directions.

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