Hi, everyone! Today is not today. Elementary particles are known to fall in two species, taking for granted the Standard Model (SM): bosons and fermions. The SM bosons are photons, gluons, W and Z bosons and the recently found Higgs … Continue reading

# Tag Archives: QFT

Hi, there! In this short note I am going to introduce you into a big problem from a simple integral I use to call “the cosmological integral” (it should be the cosmological energy density integral, but it is too long…). … Continue reading

The polylogarithm or Jonquière’s function is generally defined as Do not confuse with the logarithm integral in number theory, which is such as and . In fact, notation can be confusing sometimes … Continue reading

The year 2013 is coming to its end…And I have a final gift for you. An impossible post! This year was the Bohr model 100th anniversary. I have talked about this subject already, here, here and here. The hydrogen spectrum is very important in Astronomy, … Continue reading

Final round of this thread! Approximate methods We will evaluate the path integral (PI) using an approximation known as “saddle point”. It is a semiclassical approximation sometimes referred as the method of steepest descent. Moreover, it is based on the … Continue reading

Round 3! Fight… with path integrals! XD Introduction: generic aspects Consider a particle moving in one dimension (the extension to ND is trivial), the hamiltonian being of the usual form: The fundamental question and problem in the path integral (PI) … Continue reading

Are you gaussian? Are you normal? My second post about the path integral will cover functional calculus, and some basic definitions, properties and formulae. What is a functional? It is a gadget that produces a number! Numbers are cool! Functions … Continue reading

My next thematic thread will cover the Feynman path integral approach to Quantum Mechanics! The standard formulation of Quantum Mechanics is well known. It was built and created by Schrödinger, Heisenberg and Dirac, plus many others, between 1925-1931. Later, it … Continue reading

In this short blog post, I am going to list some of the greatest “naturalness” problems in Physics. It has nothing to do with some delicious natural dishes I like, but there is a natural beauty and sweetness related to … Continue reading

The topic today is to review a beautiful paper and to discuss its relevance for theoretical physics. The paper is: Comment on the cosmological constant and a gravitational alpha by R.J.Adler. You can read it here: http://arxiv.org/abs/1110.3358 One of the … Continue reading