Theoretical physics paper now published

My article on reheating and gravitino production in MSSM inflation is now published in The European Physical Journal C. It is a full access publication, if you are interested you can find it here:

https://link.springer.com/article/10.1140/epjc/s10052-017-5269-8

Abstract

In the framework of MSSM inflation, matter and gravitino production are here investigated through the decay of the fields which are coupled to the udd inflaton, a gauge-invariant combination of squarks. After the end of inflation, the flat direction oscillates about the minimum of its potential, losing at each oscillation about 56% of its energy into bursts of gauge/gaugino and scalar quanta when crossing the origin. These particles then acquire a large inflaton VEV-induced mass and decay perturbatively into the MSSM quanta and gravitinos, transferring the inflaton energy very efficiently via instant preheating. Regarding thermalization, we show that the MSSM degrees of freedom thermalize very quickly, yet not immediately by virtue of the large vacuum expectation value of the inflaton, which breaks the SU(3)C×U(1)YSU(3)C×U(1)Y symmetry into a residual U(1). The energy transfer to the MSSM quanta is very efficient, since full thermalization is achieved after only O(40)O(40) complete oscillations. The udd inflaton thus provides an extremely efficient reheating of the Universe, with a temperature Treh=O(108GeV)Treh=O(108GeV), which allows for instance several mechanisms of baryogenesis. We also compute the gravitino number density from the perturbative decay of the flat direction and of the SUSY multiplet. We find that the gravitinos are produced in negligible amount and satisfy cosmological bounds such as the Big Bang nucleosynthesis (BBN) and dark matter (DM) constraints.

About Quantum Prana, my logo and particle cosmology

My logo certainly carries my initials, however there’s a bit more meaning in it.

As you know from my Home page, I am a theoretical physicist, and I got my PhD at the University of Helsinki in 2010. More specifically, my field was particle cosmology with topic supersymmetric dark matter and supergravity. My papers and theses are found here.

Since I am a certified nerd, it is now clear why I use the name Quantum Prana: quantum physics, though still controversial, provides the basics for most of the physics of the last 100 years. Prana is the Sanskrit word for “life force”, which can be thought as “energy”. Thus Quantum Prana is the quantum energy which “surrounds us and penetrates us; it binds the galaxy together.” (cit.)

This is also the reason why I am called the Dark Matter Guitar 🙂

Related to that, my logo carries the q and p letters in lower case: in mathematics, they are the action-angle coordinates upon which ALL of quantum mechanics (and by extension, quantum field theory) is founded. In fact, by using Hamiltonian mechanics the pair (q,p) describes the quantum states, where q(t) is the position and p(t) is the momentum of the particle.

Starting from q and p, you get all the theory, including cool stuff like the Heisenberg indetermination principle, the Pauli exclusion principle, Schrödinger’s cats and so on.

And on top of that, I also think the symmetry of q p looks cool! 😀