Photonic crystals increase solar efficiency

Here it is a Post about my original Technological & Scientific field of Study and Training: Photonics and Optoelectronics. One of most exciting applications in these fields concerns Solar Photovoltaic Cells, its role in Renewable Energy Solutions being crucial. This Video is from Sajeev John, a University Professor at the University of Toronto Canada:




His groundbreaking work in the field of light localization that enables light to be controlled at the microscopic level has earned him an international reputation. He is a pioneering theoretician in photonic band gap (PBG) materials. This new class of optical materials presents exciting possibilities in the fields of physics, chemistry, engineering and medicine. PBG materials could eventually be used for optical communications/information processing, clinical medicine, lighting and solar energy harvesting.



Quantum Symmetry


This is a reproduction of a post in a Facebook group that I happily belong to: Quantum Physics. The post was submitted by a friend of mine in that Social Media Network: Manel Rosa Martins.

Consequences of quantum symmetry

While it makes sense that symmetries could become exact when applied to very simple objects, the immediate intuition is that such a detail should not affect the physics of such objects in any significant way.

This is in part because it is very difficult to view the concept of exact similarity as physically meaningful. Our mental picture of such situations is invariably the same one we use for large objects: We picture objects or configurations that are very, very similar, but for which if we could “look closer” we would still be able to tell the difference.

However, the assumption that exact symmetries in very small objects should not make any difference in their physics was discovered in the early 1900s to be spectacularly incorrect. The situation was succinctly summarized by Richard Feynman in the direct transcripts of his Feynman Lectures on Physics, Volume III, Section 3.4, Identical particles. (Unfortunately, the quote was edited out of the printed version of the same lecture.)

“… if there is a physical situation in which it is impossible to tell which way it happened, it always interferes; it never fails.”

The word “interferes” in this context is a quick way of saying that such objects fall under the rules of quantum mechanics, in which they behave more like waves that interfere than like everyday large objects.
In short, when an object becomes so simple that a symmetry assertion of the form F(x) = x becomes an exact statement of experimentally verifiable sameness, x ceases to follow the rules of classical physics and must instead be modeled using the more complex, and often far less intuitive, rules of quantum physics.

This transition also provides an important insight into why the mathematics of symmetry are so deeply intertwined with those of quantum mechanics. When physical systems make the transition from symmetries that are approximate to ones that are exact, the mathematical expressions of those symmetries cease to be approximations and are transformed into precise definitions of the underlying nature of the objects.

From that point on, the correlation of such objects to their mathematical descriptions becomes so close that it is difficult to separate the two.


If you please check the Wikipedia Link at the bottom of the post about Symmetry. Symmetry plays a crucial role in various fields of Knowledge, not least in Quantum Physics and Advanced Mathematics. Very good indeed.

Hello World: Welcome to Self-Organized Science & Tech

I knew you would say: that’s completely wrong…. And so I repent: here it is the correct version:

//C hello world example
#include <stdio.h>
int main()
  printf("Hello world\n");
  return 0;

 #include io




                             <Hello World>

         if var=x

            then   x= string

         else    Hello World