Ghosts in a Mirror

Abstract

We look at some dynamic geometries produced by scalar fields with both the "right" and the "wrong" sign of the kinetic energy. We start with anisotropic homogeneous universes with closed, open and flat spatial sections. A non-singular solution to the Einstein field equations representing an open anisotropic universe with the ghost field is found. This universe starts collapsing from $t\to -\infty$ and then expands to $t\to \infty$ without encountering singularities on its way. We further generalize these solutions to those describing inhomogeneous evolution of the ghost fields. Some interesting solutions with the plane symmetry are discussed. These have a property that the same line element solves the Einstein field equations in two mirror regions $|t|\ge z$ and $|t|\le z$, but in one region the solution has the \emph{right} and in the other, the \emph{wrong} signs of the kinetic energy. We argue, however, that a physical observer can not reach the mirror region in a finite proper time. Self-similar collapse/expansion of these fields are also briefly discussed.

Minor changes, new references added

Cited by in corpus (28)

• Dynamics of dark energy
• Properties of singularities in (phantom) dark energy universe
• The final state and thermodynamics of dark energy universe
• Coupled dark energy: Towards a general description of the dynamics
• Entropy and universality of Cardy-Verlinde formula in dark energy universe
• The fate of (phantom) dark energy universe with string curvature corrections
• More General Sudden Singularities
• New Isotropic and Anisotropic Sudden Singularities
• Dark energy cosmology with generalized linear equation of state
• Phantom Inflation and Primordial Perturbation Spectrum
• On the evolution of universes in quadratic theories of gravity
• Phantom-like GCG and the constraints of its parameters via cosmological dynamics
• Phantom Cosmic Dynamics: Tracking Attractor and Cosmic Doomsday
• Phantom k-essence cosmologies
• Phantom Field with O(N) Symmetry in Exponential Potential
• Slow-roll parameters in braneworld cosmologies
• Classical Stability of Sudden and Big Rip Singularities
• Dual interacting cosmologies and late accelerated expansion
• Holographic Dark Energy and the Universe Expansion Acceleration
• Cosmic Dynamics in the Chameleon Cosmology
• The Dominant Balance at Cosmological Singularities
• Gravity of a static massless scalar field and a limiting Schwarzschild-like geometry
• Interacting fluids generating identical, dual and phantom cosmologies
• Simple analytic model of wormhole formation
• Form invariant transformations between n-- and m-- dimensional flat Friedmann--Robertson--Walker cosmologies
• The universe dynamics in the tachyon cosmology with non-minimal coupling to matter
• Pre-big bang collapsing universe from modern Kaluza-Klein theory of gravity
• Anisotropic Evolution Driven by Kinetic Term