Physics / Fizik

Permanent URI for this collectionhttps://hdl.handle.net/11147/6

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Institution Author: search.filters.institutionAuthor.Erdem, RecaiSubject: search.filters.subject.Space-time

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Now showing 1 - 3 of 3
  • Article
    Citation - WoS: 14
    Citation - Scopus: 15
    A Symmetry for Vanishing Cosmological Constant: Another Realization
    (Elsevier Ltd., 2006) Erdem, Recai
    A more conventional realization of a symmetry which had been proposed towards the solution of cosmological constant problem is considered. In this study the multiplication of the coordinates by the imaginary number i in the literature is replaced by the multiplication of the metric tensor by minus one. This realization of the symmetry as well forbids a bulk cosmological constant and selects out 2 (2 n + 1)-dimensional spaces. On contrary to its previous realization the symmetry, without any need for its extension, also forbids a possible cosmological constant term which may arise from the extra-dimensional curvature scalar provided that the space is taken as the union of two 2 (2 n + 1)-dimensional spaces where the usual 4-dimensional space lies at the intersection of these spaces. It is shown that this symmetry may be realized through space-time reflections that change the sign of the volume element. A possible relation of this symmetry to the E-parity symmetry of Linde is also pointed out.
  • Article
    Citation - WoS: 8
    Citation - Scopus: 9
    A Symmetry for the Vanishing Cosmological Constant
    (IOP Publishing Ltd., 2007) Erdem, Recai
    Two different realizations of a symmetry principle that impose a zero cosmological constant in an extra-dimensional set-up are studied. The symmetry is identified by multiplication of the metric by minus one. In the fist realization of the symmetry this is provided by a symmetry transformation that multiplies the coordinates by the imaginary number i. In the second realization this is accomplished by a symmetry transformation that multiplies the metric tensor by minus one. In both realizations of the symmetry the requirement of the invariance of the gravitational action under the symmetry selects out the dimensions given by D ≤ 2(2n + 1), n ≤ 0, 1, 2..., and forbids a bulk cosmological constant. Another attractive aspect of the symmetry is that it seems to be more promising for quantization when compared to the usual scale symmetry. The second realization of the symmetry principle is more attractive in that it is possible to make a possible brane cosmological constant zero in a simple way by using the same symmetry, and the symmetry may be identified by reflection symmetry in extra dimensions.
  • Article
    Citation - WoS: 5
    Citation - Scopus: 7
    Higgs Field as the Gauge Field Corresponding To Parity in the Usual Space-Time
    (World Scientific Publishing Co. Pte Ltd, 1998) Erdem, Recai
    We find that the local character of field theory requires the parity degree of freedom of the fields to be considered as an additional discrete fifth dimension which is an artifact emerging due to the local description of space-time. Higgs field can be interpreted as the gauge field corresponding to this discrete dimension. Hence the noncommutative geometric derivation of the standard model follows as a manifestation of the local description of the usual space-time.