On the Stability of Phantom K-essence Theories

Abstract

We show that phantom dark energy, if it is described by a K-essence theory, has three fundamental problems: first, its hamiltonian is unbounded from below. Second, classical stability precludes the equation of state from crossing the ``Lambda-barrier'', $w_{\Lambda }=-1$. Finally, both the equation of state and the sound speed are unbounded -- the first, from below, the second, from above -- if the kinetic term is not bounded by dynamics.

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References in corpus (10)

• Cosmological parameter analysis including SDSS Ly-alpha forest and galaxy bias: constraints on the primordial spectrum of fluctuations, neutrino mass, and dark energy
• Can dark energy evolve to the Phantom?
• Crossing the Phantom Divide: Dark Energy Internal Degrees of Freedom
• Perturbations of the Quintom Models of Dark Energy and the Effects on Observations
• Crossing of the w=-1 Barrier by D3-brane Dark Energy Model
• A Single Scalar Field Model of Dark Energy with Equation of State Crossing -1
• Dark-Energy Evolution Across the Cosmological-Constant Boundary
• Non-minimal coupling, exponential potentials and the $w<-1$ regime of dark energy
• Dark energy transition between quintessence and phantom regimes - an equation of state analysis
• Inflation with violation of the null energy condition

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