View in EDS HTML Full Text PDF Full Text

Quintessence-dominated cyclic universe with negative cosmological constant.

Saved in:
Bibliographic Details
Title: Quintessence-dominated cyclic universe with negative cosmological constant.
Authors: Ahmed, Nasr1 (AUTHOR) nasr.ahmed@nriag.sci.eg, Bamba, Kazuharu2 (AUTHOR) bamba@sss.fukushima-u.ac.jp
Source: European Physical Journal C -- Particles & Fields. May2026, Vol. 86 Issue 5, p1-13. 13p.
Subjects: Cosmological constant, Energy density, Dark energy, Physical cosmology, Expanding universe
Abstract: We investigate two simplified non-singular cyclic models with a negative time-varying cosmological constant to represent the non-conventional mechanism of negative cosmological constant expected to address the late-time cosmic acceleration. We show that a physically acceptable evolution with positive energy density can be realized, while negative energy density dominates in case of a positive or zero cosmological constant. In the first model, we demonstrate a sign flipping of the cosmic pressure in a quintessence-dominated universe with no violation of the null energy condition. In the second model, we propose a matter-bounce scenario with showing the crossing of the phantom divide line in the vicinity of the bounce. We find that while we get positive kinetic term and scalar potential, the sum of scalar and quantum potentials is negative. [ABSTRACT FROM AUTHOR]
Copyright of European Physical Journal C -- Particles & Fields is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Engineering Source
Full text is not displayed to guests.
FullText Links:
  – Type: pdflink
Text:
  Availability: 1
Header DbId: egs
DbLabel: Engineering Source
An: 194633929
AccessLevel: 6
PubType: Academic Journal
PubTypeId: academicJournal
PreciseRelevancyScore: 0
IllustrationInfo
Items – Name: Title
  Label: Title
  Group: Ti
  Data: Quintessence-dominated cyclic universe with negative cosmological constant.
– Name: Author
  Label: Authors
  Group: Au
  Data: <searchLink fieldCode="AR" term="%22Ahmed%2C+Nasr%22">Ahmed, Nasr</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> nasr.ahmed@nriag.sci.eg</i><br /><searchLink fieldCode="AR" term="%22Bamba%2C+Kazuharu%22">Bamba, Kazuharu</searchLink><relatesTo>2</relatesTo> (AUTHOR)<i> bamba@sss.fukushima-u.ac.jp</i>
– Name: TitleSource
  Label: Source
  Group: Src
  Data: <searchLink fieldCode="JN" term="%22European+Physical+Journal+C+--+Particles+%26+Fields%22">European Physical Journal C -- Particles & Fields</searchLink>. May2026, Vol. 86 Issue 5, p1-13. 13p.
– Name: Subject
  Label: Subjects
  Group: Su
  Data: <searchLink fieldCode="DE" term="%22Cosmological+constant%22">Cosmological constant</searchLink><br /><searchLink fieldCode="DE" term="%22Energy+density%22">Energy density</searchLink><br /><searchLink fieldCode="DE" term="%22Dark+energy%22">Dark energy</searchLink><br /><searchLink fieldCode="DE" term="%22Physical+cosmology%22">Physical cosmology</searchLink><br /><searchLink fieldCode="DE" term="%22Expanding+universe%22">Expanding universe</searchLink>
– Name: Abstract
  Label: Abstract
  Group: Ab
  Data: We investigate two simplified non-singular cyclic models with a negative time-varying cosmological constant to represent the non-conventional mechanism of negative cosmological constant expected to address the late-time cosmic acceleration. We show that a physically acceptable evolution with positive energy density can be realized, while negative energy density dominates in case of a positive or zero cosmological constant. In the first model, we demonstrate a sign flipping of the cosmic pressure in a quintessence-dominated universe with no violation of the null energy condition. In the second model, we propose a matter-bounce scenario with showing the crossing of the phantom divide line in the vicinity of the bounce. We find that while we get positive kinetic term and scalar potential, the sum of scalar and quantum potentials is negative. [ABSTRACT FROM AUTHOR]
– Name: AbstractSuppliedCopyright
  Label:
  Group: Ab
  Data: <i>Copyright of European Physical Journal C -- Particles & Fields is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.)
PLink https://search.ebscohost.com/login.aspx?direct=true&site=eds-live&db=egs&AN=194633929
RecordInfo BibRecord:
  BibEntity:
    Identifiers:
      – Type: doi
        Value: 10.1140/epjc/s10052-026-15765-2
    Languages:
      – Code: eng
        Text: English
    PhysicalDescription:
      Pagination:
        PageCount: 13
        StartPage: 1
    Subjects:
      – SubjectFull: Cosmological constant
        Type: general
      – SubjectFull: Energy density
        Type: general
      – SubjectFull: Dark energy
        Type: general
      – SubjectFull: Physical cosmology
        Type: general
      – SubjectFull: Expanding universe
        Type: general
    Titles:
      – TitleFull: Quintessence-dominated cyclic universe with negative cosmological constant.
        Type: main
  BibRelationships:
    HasContributorRelationships:
      – PersonEntity:
          Name:
            NameFull: Ahmed, Nasr
      – PersonEntity:
          Name:
            NameFull: Bamba, Kazuharu
    IsPartOfRelationships:
      – BibEntity:
          Dates:
            – D: 01
              M: 05
              Text: May2026
              Type: published
              Y: 2026
          Identifiers:
            – Type: issn-print
              Value: 14346044
          Numbering:
            – Type: volume
              Value: 86
            – Type: issue
              Value: 5
          Titles:
            – TitleFull: European Physical Journal C -- Particles & Fields
              Type: main
ResultId 1