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Giant gravitons in m-deformed backgrounds

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Title: Giant gravitons in m-deformed backgrounds


1
Giant gravitons in m-deformed backgrounds
  • R. de Mello Koch, Norman Ives, Jelena Smolic,
    Milena Smolic
  • hep-th/0509007

2
Introduction
  • Want experimental data for string theories
  • High energy experiments described by Yang-Mill
    gauge theories
  • The AdS/CFT conjecture connection between
    string theories and field theories
  • Type IIB string theory on AdS5S5
  • equivalent to
  • supersymmetric Yang-Mills on 4d Minkowski space
  • Not quite good enough

3
Introduction
  • No field theory which currently describes
    observed phenomena exhibits supersymmetry
  • Necessary to find string theories dual to
    non-SUSY field theories
  • QCD could be solved at low energy if the string
    theory dual were found
  • Then wed have plenty of data

4
Initial steps
  • Lunin and Maldacena showed how to find string
    theories dual to particular deformations of SYM
    (hep-th/0502086)
  • Frolov generalised this deformation to break all
    the SUSY (hep-th/0503201)
  • Frolov, Tseytlin and Roiban showed that the
    duality holds for rotating closed strings
    (hep-th/0507021)

5
Old favourites
  • Along the way, FRT discovered a set of BPS
    objects in the non-SUSY background
  • These are objects with charge equal to energy and
    in the SUSY setting are protected from quantum
    corrections.
  • The most famous example of a BPS object is a
    giant graviton, and there is a wealth of slick
    machinery for dealing with them

6
What is a giant graviton?
  • In our case, an S3 moving in a plane in the S5
    part of the string theory background
  • In the semi-classical limit, it has an equivalent
    description as a boundary condition for open
    string endpoints
  • Couples to 5-form flux in such a way that the
    giant expands with increasing angular momentum
    (hep-th/0003075)

7
What is a giant graviton?
  • The dual field theory operators for giants are
    quite well understood
  • Using a spin chain one can examine the dynamics
    of an open string with boundary conditions
    specified by the giant graviton (hep-th/0502172)

8
Our work
  • Found giant graviton solutions in the deformed
    background for some of the BPS states
  • Calculated the spectrum of fluctuations for these
    objects in the AdS part of the space and
    recovered known results in the appropriate limit

9
Our work
  • Generalised the spin chain approach for
    calculating open string dynamics to accommodate
    the deformations
  • From this computed a semi-classical Hamiltonian
    for the open strings
  • Calculated a semi-classical Hamiltonian from the
    string worldsheet sigma model

10
Results
  • The giants have a higher energy than the
    pointlike graviton, implying that they are
    unstable. Thus one can argue that the agreement
    in this background is a product of the dynamics,
    rather than a relic of symmetries protecting the
    objects.
  • The Hamiltonian from the deformed gauge theory
    exactly reproduces the gravity deformations.

11
Future possibilities
  • There have been signs that in another deformation
    of the S5 there may be cases when the massive
    giant has a lower energy than the point giant and
    is thus stable. This would imply that gravitons
    can acquire a mass.
  • Although SUSY was broken, the field theory still
    possessed a conformal invariance, which is not a
    feature of QCD.

12
Future possibilities
  • The spectrum for open strings attached to the
    giants should be calculated in the field theory
    and gravity descriptions, and compared.
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