Simplest cosmological model with the scalar field II. Influence of cosmological constant

Continuing the investigation of the simplest cosmological model with the massive real scalar non-interacting inflaton field minimally coupled to gravity we study an influence of the cosmological constant on the behaviour of trajectories in closed minisuperspace Friedmann-Robertson-Walker model. The transition from chaotic to regular behaviour for large values of cosmological constant is discussed. Combining numerical calculations with qualitative analysis both in configuration and phase space we present a convenient classification of trajectories.Comment: 12 pages with 2 gif figures and 2 eps figures, mprocl.sty, To appear in International Journal of Modern Physics

Quantum Cosmology and Conformal Invariance

According to Belinsky, Khalatnikov and Lifshitz, gravity near a space-like singularity reduces to a set of decoupled one-dimensional mechanical models at each point in space. We point out that these models fall into a class of conformal mechanical models first introduced by de Alfaro, Fubini and Furlan (DFF). The deformation used by DFF to render the spectrum discrete corresponds to a negative cosmological constant. The wave function of the universe is the zero-energy eigenmode of the Hamiltonian, also known as the spherical vector of the representation of the conformal group SO(1,2). A new class of conformal quantum mechanical models is constructed, based on the quantization of nilpotent coadjoint orbits, where the conformal group is enhanced to an ADE non-compact group for which the spherical vector is known.Comment: 4 pages, latex2e, uses revtex

Boundary Value Problem for Black Rings

We study the boundary value problem for asymptotically flat stationary black ring solutions to the five-dimensional vacuum Einstein equations. Assuming the existence of two additional commuting axial Killing vector fields and the horizon topology of $S^1\times S^2$, we show that the only asymptotically flat black ring solution with a regular horizon is the Pomeransky-Sen'kov black ring solution.Comment: 21 pages, 1 figur

The generality of inflation in some closed FRW models with a scalar field

The generality of inflation in closed FRW Universe is studied for the models with a scalar field on a brane and with a complex scalar field. The results obtained are compared with the previously known results for the model with a scalar field and a perfect fluid. The influence of the measure chosen in the initial condition space on the ratio of inflationary solution is described.Comment: 15 pages with 5 eps figures; small corrections in text; final version to appear in Int. J. Mod. Phys.

The Black Di-Ring: An Inverse Scattering Construction

We use the inverse scattering method (ISM) to derive concentric non-supersymmetric black rings. The approach used here is fully five-dimensional, and has the modest advantage that it generalizes readily to the construction of more general axi-symmetric solutions.Comment: v3: 2 subsections added, typos fixed, more refs, journal version. v4: a transcription error in the ADM mass fixe

Brane Inflation is Attractive

We study the phase space of initial conditions for brane inflation, and find that including the effects of the Dirac-Born-Infeld (DBI) kinetic term dramatically improves previous estimates on the amount of fine tuning of initial conditions necessary for inflation, even for models dominated by slow roll. Two effects turn out to be important for the phase space analysis: restrictions on the total available phase space due to UV effects in brane inflation, and the extension of the inflationary attractor to the DBI inflationary regime. We compare the amount of initial conditions fine tuning required for a brane inflation model and its standard field theory counterpart and find that brane inflation decreases the required tuning by several orders of magnitude.Comment: 20 pages, 6 figures; v2. references added, typos corrected, discussion clarified; v3. some numbers changed, discussion on phase space fine tuning slightly modifie

Reduction without reduction: Adding KK-monopoles to five dimensional stationary axisymmetric solutions

We present a general method to add KK-monopole charge to any asymptotically flat stationary axisymmetric solution of five dimensional General Relativity. The technique exploits the underlying SL(3,R) invariance of the system by identifying a particular element of the symmetry group which changes the asymptotic boundary condition and adds KK-monopole charge. Furthermore, we develop a set of technical tools which allow us to apply the SL(3,R) transformations to solutions produced by the Inverse Scattering method. As an example of our methods, we construct the exact solution describing a static black ring carrying KK-monopole charge.Comment: 36 pages, 3 figures, LaTeX, minor typos fixe

Joint Probabilities Reproducing Three EPR Experiments On Two Qubits

An eight parameter family of the most general nonnegative quadruple probabilities is constructed for EPR-Bohm-Aharonov experiments when only 3 pairs of analyser settings are used. It is a simultaneous representation of 3 Bohr-incompatible experimental configurations valid for arbitrary quantum states.Comment: Typo corrected in abstrac