The Early Universe Cosmology group is broadly dedicated to investigating the predictions that fundamental theories of physics may offer for the evolution of the cosmos. One prominent hypothesis suggests that the universe underwent a period of rapid expansion during inflation before transitioning to its current, relatively stable state of expansion. This implies that the large-scale structure of the universe may have been comparable to the scales of new physics or the Planck scale at the onset of inflation. Furthermore, the energy scale of inflation could reach the Grand Unified Theory (GUT) scale, which far exceeds the energy ranges accessible to terrestrial experiments. The Planck scale holds particular significance in the context of string theory and various paradigms of quantum gravity. Additionally, the post-inflationary universe was characterized by temperatures high enough to facilitate particle collisions with center-of-mass energies that are exceedingly challenging—if not impossible—to replicate in terrestrial colliders.

Over the past three decades, cosmology has entered a precision era, thanks to an impressive array of observational data. Cosmologists have developed the "Standard Model of Cosmology," known as the Lambda-CDM model, which accurately fits a wide range of cosmological observations. However, the Lambda-CDM model remains phenomenological, as its free parameters are manually adjusted without a comprehensive theoretical underpinning. Furthermore, small but notable tensions between the model and observational data have begun to emerge, potentially hinting at the existence of new physics. Recently, transient gravitational wave signals from merging binary black holes, as well as a stochastic gravitational wave background, have been detected. The latter may have originated from early universe phenomena, offering a new window into the cosmos's infancy.

Some of the most pressing questions in theoretical cosmology include:

·  Did inflation occur in the early universe, and what were its underlying mechanisms?

·  How were large-scale structures generated, and how have they evolved over time?

·  What is the nature of dark matter?

·  What is the nature of dark energy?

·   Is the Lambda-CDM model fully consistent with the latest observational data, and if not, how can these tensions be resolved or mitigated?

Members of the Early Universe Cosmology group at the IPM School of Physics are actively engaged in research on topics such as inflation, drawing insights from both fundamental theories and effective field theory perspectives. Their work also encompasses cosmological perturbation theory, cosmological tensions, and the lensing signatures of accelerating or rotating black holes.

The individuals currently active in the Early Universe Cosmology group at IPM are:

  -  Moslem Ahmadvand 
  -  Zahra Davari
  -  Kazem Rezazadeh
  -  Abasalt Rostami