About

Our universe is expanding. This astonishing fact has consequences far beyond one’s imagination. To understand, let us reverse the arrow of time: the universe is shrinking, shrinking means denser, and denser means hotter. As we move towards the beginning of time, the temperature rises, stars and galaxies melt into atoms, electrons gain enough energy and undress the atoms and atoms further break into protons and neutrons which in turn break into more elementary particles: the quarks and gluons. Our early universe is a hot plasma composed of the most elementary particles in nature. How far can we go? Common sense (and classical physics) leads us to a singular point, a point-like universe, the beginning of time. The celebrated Big Bang.

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However, our physical understanding stopped much before. Physicists have developed a theory, known as the Standard Model (SM) of particle physics that describes in detail the constituents of matter and the fundamental interactions among them. They have built huge particle accelerators that explore the theory to unprecedented precision. But as the temperature exceeds the energies reached by our fastest accelerators, the physics becomes unknown. The higher we go in energies, the blinder, we the physicists, become. As we go up in energy, new particles and physical laws emerge, beyond those described in the Standard Model. A different way to learn about physics at energies beyond the reach of accelerators is to look back in time at the early universe. Our universe is the fruitful outcome of a one-time, uncontrolled, experiment that we now live to enjoy and to use as a source of learning about the most fundamental laws of nature.

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A new era is commencing.  With a plethora of terrestrial experiments, astronomical earth-based observatories, and satellite missions, along with the rapid advancement of computational tools and big-data analyses, it is guaranteed that a new and revolutionary understanding of our universe will emerge in the next decade, possibly addressing some of the most fundamental conundrums such as: 

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• What is dark matter?  Roughly 85% of the matter in our universe is composed of an unknown form of matter, very different from those we see around us.  Discovering the identity of this substance is considered to be one of the most challenging and important open problems in physics.
   

• What is dark energy?  Most of the energy density in our universe is not composed of matter, but rather,  a mysterious form of energy, very different from anything familiar, that dominates the late-time dynamics of our universe.   What is the nature of this dark energy is one of the most difficult open questions scientists are facing to date.
   

• What is the origin of the matter-antimatter asymmetry?  In the early 20th century, Dirac’s revolutionary understanding of quantum mechanics implied that every particle must be accompanied by its antiparticle.   However, these antiparticles are only rarely seen in our universe.  Where is all the antimatter? The dynamics that rendered our universe asymmetric are yet to be understood.
   

• Why is our universe so big and flat?  The huge volume and flat form of our universe are still a topic of ongoing research in cosmology. A possible explanation is the inflationary cosmology theory, which suggests that in the early universe, a period of rapid expansion occurred, leading to a homogeneous and isotropic universe. This theory also suggests that quantum fluctuations were stretched to cosmic scales, eventually forming structures in the universe. However, the smoking-gun evidence for this epoch is still missing and much of the physical mechanism that drove inflation remains a mystery.
   

To address these questions and advance our understanding of the fundamental laws of nature, we must unite forces and bring together researchers from distinct fields of research, including experimental high-energy physics, theoretical particle physics, observational astrophysics, astroparticle physics, and cosmology.  Together we are laying the grounds for unveiling the inner workings of our universe.