## Analyzing the Universe: Data, Interpretation, Theory (AUDIT)

A research project led by Prof. Dr. Arshad Momen with Dr. Khan Asad and Dr. Jewel Kumar Ghosh as co-I

Our research will focus on the most topical issues of physics and astronomy. We will develop pipelines to analyze data and answer the most pressing questions of contemporary cosmology, high energy physics and astrophysics. We will work on 3 major topics.

**Dark matter, galaxies and their clusters:**Within the framework of the LambdaCDM model, our universe may contain a sizable amount of dark matter. Dark matter candidates can arise in simple extensions of the standard model (like massive neutrinos) or beyond standard models (BSM) involving new particles from SUSY or GUT. However, one not only needs to understand their nature but their distribution in the universe as well, especially in galaxies and clusters of galaxies. We will investigate different dark matter candidates and their observability using modern radio and x-ray telescopes. Aside from dark matter detection, many astrophysical theories can be tested using these observations of clusters of galaxies.**Cosmological modeling and observation:**Einstein’s General Relativity (GR) is the most successful theoretical basis of modern cosmology till date. The goal of modern cosmologists is to construct various cosmological models and constrain their parameters both within and beyond GR. While GR is successful in explaining many cosmological questions, its applicability during the epochs of the early universe remains dubious where quantum and thermal effects also play significant roles. Going beyond Einstein requires two major modifications: i) include quantum effects, ii) include higher derivative terms. Both these modifications can lead to interesting implications on the cosmological observations. Our main objective within this topic is to predict observable implications of various cosmological and astrophysical models and test them using the observed data.**String theory and its cosmological applications:**String Theory is one of the leading candidates to reconcile gravitation and quantum field theory, and thereby a quantum theory of gravity. While Einstein’s idea of space-time led to a 4-dimensional view of the universe, consistent String Theory requires a 10-dimensional space-time. This prompts the question about the existence of the rest 6 dimensions on top of the usual 4-dimensions. String Theory answers this question by invoking a mechanism of compactification, where the extra 6-dimensions are compactified, and too small to probe by the experiments at hand. Though direct detection of these compactified dimensions in LHC has so far been unsuccessful, Early Universe cosmology provides a fertile ground where the presence of these extra dimensions can have a detectable fingerprint.

Follow a manual added link### Prof. Dr. Arshad Momen

Department of Physical Sciences

Principal Investigator

Follow a manual added link### Dr. Khan Asad

Department of Physical Sciences

co-Investigator

Follow a manual added link### Dr. Jewel Kumar Ghosh

Department of Physical Sciences

co-Investigator

We will do theoretical studies and data collection in parallel from the very beginning of the project because the theoretical predictions have to be tested using the data. The testing of predictions will be done from the mid period of the project.

**Data:**For Topic 1, we plan to collect data from three different sources: simulation of baryonic matter creation from dark matter, simulation of electromagnetic radiation from baryonic matter, and finally observations of clusters of galaxies from radio and x-ray telescopes. For Topic 2, we plan to get data from the most recent radio telescopes including LOFAR (The Netherlands) and MeerKAT (South Africa) and the simulated observations of the upcoming SKA (South Africa and Australia). Simulations of cosmological signals can also be used. Finally for Topic 3, we can collect data from simulations of the 21-cm signal and related simulated observations.**Theory:**For Topic 1, we intend to explore theories of indirect detection of dark matter and the emission mechanisms of electromagnetic radiation from galaxies and clusters of galaxies. For the other topics, we plan to work on both standard and non-standard cosmological models. Aside from predicting various implications of the standard cosmological model, we wish to investigate several other projects using holography as a tool. Holography, which is also known as the AdS/CFT correspondence, is a duality between a gauge theory and gravity. This is especially useful when the gauge theory is strongly coupled, and the available perturbative tools are limited in their usages. Using the techniques from holography, we intend to study: 1) holographic cosmology, 2) Schwinger-Keldysh physics, 3) Coleman-de Luccia instanton solution in the context of cosmology.**Interpretation:**We plan to use different data analysis techniques and statistical methods for fitting our models with the data. For example, in Topic 1, Bayesian statistical modeling and wavelet and curvelet analysis will be used. The cosmology topics will include the use of various techniques including Monte Carlo Markov Chain and machine learning.