LOG#195. Quantum theory of photon spin states.

This blog post is dedicated to my friend, Sergio Lukic. He wrote it as undergraduate student, and I got his permission to publish it here, on my blog. This article exposes a treatment of photon polarization using the quantum features … Continue reading

LOG#189. Fundamental challenges.

The marriage between gravity and quantum mechanics is “complicated”. The best physicists and brightest minds have tried, but only with partial success. String/superstring theory, now M-theory, is a curious story. The another story is canonical quantum gravity, or loop quantum … Continue reading

LOG#180. Hadronic mysteries.

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

LOG#150. Bohr and Doctor Who: A=mc³.

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

LOG#148. Path integral (III).

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

LOG#146. Path integral (I).

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

LOG#141. Basic QFT in curved ST(I).

This post begins a thread about Quantum Field Theory (QFT) in curved spacetime (ST). They are based on some of my notes about the subject. Enjoy it! I. LIMITS FROM QUANTUM MECHANICS AND GENERAL RELATIVITY. The Einstein-Hilbert action in General … Continue reading

LOG#136. Flavor ν mixtures.

Neutrino oscillations are one of the most surprising “sounds” in the whole Universe. Since neutrinos do oscillate/mix, they are massive. And due to mass, they can experiment “mixing” or “changes” of flavor (mass and flavor basis are different!). Even more, … Continue reading

LOG#113. Bohr’s legacy (I).

Dedicated to Niels Bohr and his atomic model (1913-2013) 1st part: A centenary model This is a blog entry devoted to the memory of a great scientist, N. Bohr, one of the greatest master minds during the 20th century, one … Continue reading

LOG#099. Group theory(XIX).

Final post of this series! The topics are the composition of different angular momenta and something called irreducible tensor operators (ITO). Imagine some system with two “components”, e.g., two non identical particles. The corresponding angular momentum operators are: The following … Continue reading