Naonori S. Sugiyama, Teppei Okumura, David N. Spergel

Yes. Future CMB experiments such as Advanced ACTPol and CMB-S4 should achieve measurements with S/N of $> 0.1$ for the typical galaxies in redshift surveys. These measurements will provide complementary measurements of the growth rate of large scale structure $f$ and the expansion rate of the Universe $H$ to galaxy clustering measurements. This paper emphasizes that there is significant information in the anisotropy of the relative pairwise kSZ measurements. We expand the relative pairwise kSZ power spectrum in Legendre polynomials and consider up to its octopole. Assuming that the noise in the filtered maps is uncorrelated between the positions of galaxies in the survey, we derive a simple analytic form for the power spectrum covariance of the relative pairwise kSZ temperature in redshift space. While many previous studies have assumed optimistically that the optical depth of the galaxies $\tau_{\rm T}$ in the survey is known, we marginalize over $\tau_{\rm T}$, to compute constraints on the growth rate $f$ and the expansion rate $H$. For realistic sure parameters, we find that combining kSZ and galaxy redshift survey data reduces the marginalized $1$-$\sigma$ errors on $H$ and $f$ by $\sim50$-$70\%$ compared to the galaxy-only analysis.

Stefano Viaggiu

This paper is devoted to the study of the statistical mechanics of trapped gravitons obtained by 'trapping' a spherical gravitational wave in a box. As a consequence, a discrete spectrum dependent on the Legendre index $\ell$ similar to the harmonic oscillator one is obtained and a statistical study is performed. The mean energy $<E>$ results as a sum of two discrete Planck distributions with different dependent frequencies. As an important application, we derive the semiclassical Bekenstein-Hawking entropy formula for a static Schwarzschild black hole by only requiring that the black hole internal energy $U$ is provided by its ADM rest energy, without invoking particular quantum gravity theories. This seriously suggests that the interior of a black hole can be composed of trapped gravitons at a thermodynamical temperature proportional by a factor $\simeq 2$ to the horizon temperature $T_h$.

Timothy Clifton, Bernard Carr, Alan Coley

In this paper we explore the idea that black holes can persist in a universe that collapses to a big crunch and then bounces into a new phase of expansion. We use a scalar field to model the matter content of such a universe near the time of the bounce, and look for solutions that represent a network of black holes within a dynamical cosmology. We find exact solutions to Einstein's constraint equations that provide the geometry of space at the minimum of expansion and that can be used as initial data for the evolution of hyperspherical cosmologies. These solutions illustrate that there exist models in which multiple distinct black holes can persist through a bounce, and allow for concrete computations of quantities such as number density. We then consider solutions in flat cosmologies, as well as in higher-dimensional spaces (with up to nine spatial dimensions). We derive conditions for the black holes to remain distinct (i.e. avoid merging) and hence persist into the new expansion phase. Some potentially interesting consequences of these models are also discussed.

Özenç Güngör, Bryan W. Lynn, Glenn D. Starkman

The weak-scale $U(1)_Y$ Abelian Higgs Model (AHM) is the spontaneous-symmetry-breaking (SSB) gauge theory of a complex scalar $\phi$ and a vector $A^\mu$. In Lorenz gauge, the SSB AHM has: a massless pseudo-scalar $\pi$; a conserved (up to gauge-fixing terms) $U(1)_Y$ global physical current; no conserved $U(1)_Y$ charge; and a Goldstone Theorem, where $\tilde \pi$ in the Kibble representation becomes a true massless Nambu-Goldstone boson (NGB). Two towers of "1-soft-pion" SSB global WTI govern the $\phi$-sector. The 1$^{st}$ tower gives relations among connected off-shell Green's functions, and powerful constraints on the all-loop-orders $\phi$-sector effective AHM Lagrangian. The 2$^{nd}$ tower, governing on-shell connected T-matrix elements, further severely constrains the physics. It guarantees IR finiteness for zero NGB mass; includes the Lee-Stora-Symanzik (LSS) Theorem, forcing the on-shell T-matrix element with only two external pseudoscalar legs to vanish; and is the source of an additional NGB global shift symmetry. Using the Green's functions and the LSS Theorem of the theory, we construct the manifestly symmetric quantum effective potential of the scalar sector of the Goldstone mode of the AHM, in the Lorenz gauge, to all orders in quantum loops. To do so, we solve the Ward Takahashi identities of the theory recursively, and express arbitrary $\phi$-sector Green's functions in terms of those with no external scalar legs and an even number of pseudoscalar legs. The resulting expression for the effective potential is much easier to evaluate at a given order in quantum loops, since many fewer diagrams need be computed for a given number of external $\phi$ legs. In the Kibble representation, the so-constructed effective scalar potential is gauge-independent.