Regarding axion electrodynamics in the background flat FRW universe, we show that cosmological birefringence arises from an adiabatic noncyclic geometric phase that appears in the quantum state of photons because of their interaction with the axion field. We also show that the axion electrodynamics is equivalent to standard electrodynamics in time-dependent bi-isotropic magnetoelectric Tellegen media, which serves as an analogue system that can simulate cosmological birefringence.
We study tensor perturbations around the most general cosmologically symmetric backgrounds in a class of teleparallel gravity theories known as New General Relativity. These theories comprise a one-parameter class, which is fully consistent with observations at the post-Newtonian level, and which contains the teleparallel equivalent of General Relativity as a special case. We find that for a particular class of cosmological background geometries these theories exhibit gravitational wave birefringence and dispersion, i.e., the dispersion relation for gravitational waves depends on their polariz…
In the context of the metric-affine Chern-Simons gravity endowed with projective invariance, we derive analytical solutions for torsion and nonmetricity in the homogeneous and isotropic cosmological case, described by a flat Friedmann-Robertson-Walker metric. We discuss in some details the general properties of the cosmological solutions in the presence of a perfect fluid, such as the dynamical stability and the emergence of big bounce points, and we examine the structure of some specific solutions reproducing de Sitter and power law behaviours for the scale factor. Then, we focus on first-ord…
We investigate entanglement production by inhomogeneous perturbations over a homogeneous and isotropic cosmic background, demonstrating that the interplay between quantum and geometric effects can have relevant consequences on entanglement entropy, with respect to homogeneous scenarios. To do so, we focus on a conformally coupled scalar field and discuss how geometric production of scalar particles leads to entanglement. Perturbatively, at first order we find oscillations in entropy correction, whereas at second order the underlying geometry induces mode-mixing on entanglement production. We t…
We detail a novel theoretical prediction that a geometric torsion model for scalar field dark matter could lead to oscillations, on readily probeable timescales, in the time evolution of cosmological redshifts of astronomical sources with qualitatively distinct behavior at different redshift scales (larger or smaller than z ~ 0.1). We present an analysis of extant spectroscopy data from the Australian Dark Energy Survey (OzDES) to assess whether such signals are present across a wide array of cosmological sources and baseline redshifts on the six-year timescale of OzDES. While a simple Fourier…
We present a cosmological model arising from a gravitational theory with an infinite tower of higher-order curvature invariants that can reproduce the entire evolution of the Universe: from inflation to late-time acceleration, without invoking an inflaton nor a cosmological constant. The theory is Einsteinian-like. The field equations for a Friedmann-Lemaître-Robertson-Walker metric are of second-order and can reproduce a late-time evolution that is consistent with the acceleration provided by the cosmological constant at low redshift. Our results force us to reinterpret the nature of dark ene…
In this paper, we have investigated some accelerating cosmological models at the backdrop of an anisotropic metric in an extended gravity theory. Two viable cosmological models one with a little rip behaviour and the other with a hyperbolic form of Hubble parameter have been constructed. The dynamical aspects of the models along with some physical and geometrical parameters are analysed. Both the models presented here evolve in the phantom-like region and overlap with $Λ$CDM model at late times. We carried out a geometrical diagnosis of the model to show the viability of the models.
Consistency of LCDM with Geometric and Dynamical Probes
LCDM宇宙学模型假设存在一个小的宇宙学常数，以解释观测到的宇宙加速膨胀。尽管在过去的十年里宇宙学数据的质量有了很大的提高，但它仍然是最简单的模型，非常适合（几乎）所有的宇宙学观测。在这次演讲中，我回顾了LCDM提供的越来越成功的拟合最近的宇宙膨胀的几何探测数据。我还简要讨论了一些新出现的缺点，试图适应特定类别的数据（如宇宙速度偶极子流和集群晕配置文件）的模型。最后，我总结了最近的结果，理论上预测的物质过密度（$δ_m=\frac{δρ_m}{ρ_m}$）的演变（宇宙膨胀的动力学探测），强调其规模和规范的依赖大宇宙尺度的背景下，广义相对论。一个新的标度相关参数化可以精确地描述甚至在大于100 h ^{-1}Mpc的标度上的微扰增长率，它是在较小的宇宙学标度上有效的著名的标度无关参数化f（a）= \omms（a）^γ的直接推广.
In this paper, using the concept of Lewis Riesenfeld invariant quantum operator method for finding continuous eigenvalues of quantum mechanical wave functions we derive the analytical expressions for the cosmological geometric phase, which is commonly identified to be the Pancharatnam Berry phase from primordial cosmological perturbation scenario. We compute this cosmological geometric phase from two possible physical situations,(1) In the absence of Bell's inequality violation and (2) In the presence of Bell's inequality violation having the contributions in the sub Hubble region ($-kτ\gg 1$)…
Exact formula for geometric quantum complexity of cosmological perturbations
Institute of Theoretical Physics, Jagiellonian University（雅盖隆大学理论物理研究所）；Doctoral School of Exact and Natural Sciences, Jagiellonian University（雅盖隆大学精确与自然科学学院）
On the Cosmological Constant in Pre-geometric Gravity
Sichuan University（四川大学）；Center for Theoretical Physics, College of Physics Science and Technology, Sichuan University（四川大学物理科学与技术学院理论物理中心）；Laboratori Nazionali di Frascati INFN（INFN弗拉斯卡蒂国家实验室）；Scuola Superiore Meridionale（南方高等学院）；INFN Sezione di Napoli（INFN那不勒斯分部）
Geometric origin of the cosmological constant from Einstein-Chern-Simons gravity compactified to four dimensions
Universidad del Bío-Bío（比奥比奥大学）；Pontificia Universidad Católica de Valparaíso（天主教瓦尔帕莱索大学）；Universidad de Concepción（康塞普西翁大学）；Universidad Arturo Prat（阿图罗·普拉特大学）
