LOG#191. The hooke and the dyson.

Hello, metriplectic followers and friends! I have often written about Stoney units or Planck units in this blog. Indeed, I have a complete thread about systems of units. For Stoney and Planck units, you get some basic units of S.I. … Continue reading

LOG#181. Duality and gravity: a short note.

The 2nd superstring revolution circled/circles about (electromagnetic) duality. In D=4 (or general space-time), duality transformations for the electromagnetic field strength read and for the dual field 2-curvature They are true symmetry for the Maxwell equations in vacuum, , and for … Continue reading

LOG#168. D-dimensional laws(III).

The question of the origin of mass is one of the more important issues in theoretical physics. The existence (or not) of extra dimensions of space and time will likely affect to the final solution of this unsolved problem. The … 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#149. Path integral(IV).

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

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#105. Einstein’s equations.

In 1905,  one of Einstein’s achievements was to establish the theory of Special Relativity from 2 single postulates and correctly deduce their physical consequences (some of them time later).  The essence of Special Relativity, as we have seen, is that  … Continue reading

LOG#036. Action and relativity.

The hamiltonian formalism and the hamiltonian H in special relativity has some issues with the definition. In the case of the free particle one possible definition, not completely covariant, is the relativistic energy There are two others interesting scalars in … Continue reading