The Equation of State of Novel Double-Field Pure K-Essence for Inflation, Dark Matter and Dark Energy

Feb 6, 2024
13 pages
Published in:
  • Universe 10 (2024) 6, 235,
  • Universe 10 (2024) 235
  • Published: May 24, 2024
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Abstract: (MDPI)
K-essence theories are usually studied in the framework of a single scalar field . Namely, the Lagrangian of K-essence is the function of the single scalar field and its covariant derivative. However, in this paper, we explore a double-field pure K-essence, i.e., the corresponding Lagrangian is the function of covariant derivatives of double scalar fields without a dependency on scalar fields themselves. This is why we call it double-field pure K-essence. The novelty of this K-essence is that its Lagrangian contains the quotient term of the kinetic energies from the two scalar fields. This results in the presence of many interesting features; for example, the equation of state can be arbitrarily small and arbitrarily large. In comparison, the range of the equation of state for quintessence is to . Interestingly, this novel K-essence can play the role of an inflation field, dark matter, or dark energy by appropriately selecting the expressions of Lagrangian.
Note:
  • 12 pages,18 figures
  • K-essence
  • dark energy
  • field theory: scalar: multiple
  • derivative: covariance
  • energy: kinetic
  • dark energy
  • black hole
  • dark matter
  • equation of state
  • inflation: model