So back to the lovely Conway Hall for another Interesting.

After (the now obligatory ?) Final Countdown singalong Russell wandered on to say hello and to give various thanks to various people including (perhaps most importantly) a salute to those who had brought home made cake. And then without any further ceremony Interesting09 began.

#01 Tom Loosemore was up first talking about the race to sail faster than 50 knots. Starting the day was always going to be difficult however Tom did admirably well despite the first of many IT gremlins (which kind of added to the day). He explained that the sails on yachts are pulled not pushed (which I’d never really thought of before) and explained the concept of the pressure on a daggerboard by the use of an apple pip. He was passionate, knowledgeable and as such a great start to the day.

#02 Jess Greenwood then spoke about why the least interesting thing about sport is the score, and that how the game stays the same but the world around it changes almost constantly.

#03 Robert Brook then discussed the concept of gentleman without the use of his excellent slide (which you can see here) due to the first proper IT failure of the day.

#04 Toby Barnes gave us a brief history of cheating in video-games from his earliest experiences with the legendary Manic Miner and the subsequent use of the Konami Code. He also spoke of games having “more game” about being less linear, about not simply stopping when a player gets to a certain point in a game that he cannot progress past.

#05 Leila Johnston read from her book, ‘The Enemy of Chaos’ which according to extracts read (and the reviews on her website) is a very funny book. She also gave some excellent advice regarding the production of a book : “Get you cover designed after you’ve got a plot”.

#06 Cait Hurley Spoke briefly on Arthur Jefferson aka Stan Laurel’s dad. Who as well as being Stan Laurel’s dad, was born on the 12th September, and was a quite remarkable gentleman (although perhaps I’ll have to defer to Robert Brook on that).

#07 Alby Reid’s Told us that “Everything You Know About Nuclear Power is Wrong”. Which was fine by me because my knowledge of nuclear is sketchy to say the least. By day it seems Alby is a physics theory teacher – I think if physics theory had been taught to me with the passion he showed for his subject I might not have got a U in my physics theory A Level, (I actually got another U when I retook it so my heart perhaps wasn’t in it eh ?).

#08 Katy Lindemann then wrapped up the first session with an enthusiastic talk about her love of robots, which as Russell has already pointed out elsewhere is difficult to argue with. The tweenbots she introduced us to were particularly endearing.

* Which appears above the stage at Conway Hall.

Notes From Session #02 Coming Soon

physics theory Central
When today’s soldiers enter combat, they’re better protected from explosions than the military personnel of any previous war. Ultra-strong helmets shield them from the flying shrapnel of homemade bombs; high-tech cushioning cradles their skulls during sudden impacts with the ground. But because modern soldiers are surviving explosions that would have taken the lives of Vietnam-era infantrymen, army hospitals are seeing a rise in a particularly painful war wound—traumatic brain injury (TBI).

TBI can range from a simple concussion to damage with long-term effects, including impaired cognitive abilities and even anxiety and depression. New research is helping to explain how those injuries come about, potentially pointing the way to helmet designs to reduce brain damage. Using code originally designed to simulate how a detonated weapon rattles a building or tank, physicists at Lawrence Livermore National Laboratory in California and the University of Rochester in New York modeled an all-too-real situation: a 5-pound bomb exploding 15 feet from a soldier’s head. Their goal was to understand the effects of the high-speed shock wave mechanics that follows an explosion.

I may not have mentioned it in all my classes, but your first extra credit opportunity for the year will be to explain the humor in the statement in the title of this post.  I certainly wouldn’t say it is hilarious, but with the corny sense of humor that Physicists and physics theory teachers and students have, it is mildly funny.

In order to receive the extra credit, please email your response to my by the start of school on Tuesday 9/15/09 (even if I told you a different day in class…)

“Having created quantum superpositions of photons, atoms, and even molecules, scientists are currently preparing to do the same for larger objects — namely viruses.

The technique will involve storing a virus in a vacuum and then cooling it to its quantum-mechanical ground state in a microcavity. Zapping the virus with a laser then leaves it in a superposition of its ground state and an excited one.

That’s no easy task, however. The virus will have to survive the vacuum, behave like a dielectric, and appear transparent to the laser light, which would otherwise tear it apart.

Now a group of researchers has worked out that several viruses look capable of surviving the superposition process, including the common flu virus and the tobacco mosaic virus. They point out that after creating the superposition, scientists will be able to perform the Schrodinger’s Cat experiment for the first time, which should be fun (but less so for the virus).”

READ MORE…

Hay artículos con un título que nos obliga a leerlos sin excusa. Aunque sabemos que poco podremos aprender, nadie puede resistir la tentación. Ese es el caso de Abhijnan Rej, “Turing’s Landscape: decidability, computability and complexity in string theory,” ArXiv, Submitted on 10 Sep 2009, artículo enviado al 2º FQXI Essay Contest, cuyo foco es “What is Ultimately Possible in physics theory?” Muchos se preguntarán “¿qué tiene que ver la informática teórica con el problema del vacío en teoría de cuerdas?” Poco quizás, pero el autor conjetura una conexión íntima entre ambas y trata de argumentarla de manera que sea “fácil” de leer para todos. Permitidme que os abra la boca al respecto.

La teoría de cuerdas proclama la unificación a alta energía (en la escala de Planck) de la mecánica cuántica y de la gravedad, sin embargo, a baja energía nadie ha sido capaz de obtener el modelo estándar, la realidad que conocemos. El mayor problema de la teoría de cuerdas es que permite prácticamente cualquier cosa a baja energía. A este problema se le llama “el problema del vacío” (string landscape problem). Os recuerdo que el vacío es el universo sin cuerdas, es decir, no está vacío, está relleno de las partículas elementales (puntuales) que constituyen la materia y la energía que observamos. El espacio de configuraciones para el vacío en teoría de cuerdas tiene una cardinalidad estimada de 10⁵⁰⁰ (un número inmenso e inimaginable). Como lo predice todo, la teoría de cuerdas  no predice nada. Es por lo que algunos afirman que es una teoría no falsable.

¿Se podrá determinar alguna vez el vacío correcto de la teoría de cuerdas? El autor siguiendo ideas previas de Nabutovsky, Weinberger y otros, propone que el espacio de configuración de los posibles vacíos tiene una estructura fractal discreta, lo que le lleva a considerar el problema de su calculabilidad (o computabilidad). ¿Es calculable el vacío correcto? Dados dos puntos del espacio de configuración, ¿se puede decidir si corresponden a la misma física? El autor argumenta que estos problemas son computacionalmente intratables.

El modelo estándar utiliza simetrías gauge descritas mediante grupos de Lie (en concreto, SU(3)×SU(2)×U(1) módulo Z/6Z) para describir todas las partículas elementales mediante las representaciones de sus álgebras de Lie (generadores del grupo) asociadas. El autor recuerda que la descomposición de un grupo de Lie en sus subgrupos es un problema NP-completo (resultado un teorema clásico de la teoría de la complejidad computacional). Por lo que saber si el modelo estándar está incluido en el grupo de simetrías de un vacío dado es computacionalmente muy costoso.

¿Es continuo o discreto el espacio de configuración para los posibles vacíos en teoría de cuerdas? Un artículo de Acharya y Douglas en 2006 argumentó en base a la teoría M que es discreto, por lo que existiría una distancia mínima en el espacio de configuración entre cada par de vacíos que representan física diferente. Sin embargo, el problema de determinar si entre dos vacíos hay una distancia mínima es no decidible, en base a un teorema de Novikov que afirma que en más de 5 dimensiones es imposible decidir si dos variedades diferenciables son difeomorfas (”iguales” entre sí).

Cada posible vacío en el espacio de configuración corresponde a una compactificación (una variedad de Calabi-Yau) que está caracterizada por unos números llamados periodos. ¿Qué números reales pueden ser periodos de una variedad de Calabi-Yau? Un artículo de Yoshinaga ha demostrado que todos los periodos (reales) son números calculables en el sentido de Turing. ¿Se puede determinar si dos conjuntos de periodos corresponden a la misma variedad de Calabi-Yau, o sea, son equivalentes entre sí? Este problema, según el autor del artículo, tiene visos de ser computacionalmente intratable, aunque no hay resultados matemáticos concluyentes al respecto. En su caso, decidir computacionalmente cuál es el vacío correcto resultará prácticamente imposible.

En resumen, un artículo curioso que nos recuerda lo profundo de las matemáticas en la física moderna.

After eating, people usually put their remaining food inside a bowl and use the platic wrap to cover it on the top of it. And the mystery is, why is the platic wrap stick to the bowl or even itself? And does it work on metal bowl, too?

Those are the mysterious events that take place in our real life. However, it seems to be only a few people would notice and try to come up an adequate explanation. Most of the people are just knowing that, but they wouldn’t know the reason behind it. And those people also include me. I don’t know the reason for that, either. But, I am trying to come up with my own explanations that are persuasive.

My explanation is the following:

The plastic wrap is a kind of material that will result in electron transfer when you attemp to put in onto the other objects, such as bowls. And I think that because the electrons transfer from the one to the other, it will result in one become a little bit positive and the other become a little bit negative. (They were both neutral at beginning. ) Everybody knows that positives will attract with the negatives, and that’s the reason why that works. (In my explanation )

And that didn’t work on a matal bowl because the matals are electricity condictors, which means that the elctrons are freely moving in the metal bowl. And since the excess electrons on the plastic wrap are all transfer out to the metal bowl, there will be like zero in net charge (neutral) on the platic wrap. So the plastic wrap can no longer stick to the metal bowl. But on the other hand, non-metal bowl will leave the excess electrons on the plastic wrap still. So there are charges differences between them. (plastic wrap is charged, and the bowl is not charged.) Those two things will stick to each other.

Sorry about the wordings, I think I might not use them properly. But I think that makes sense for, at least, myself.  But I don’t know how to explan things in an imagination way, which people can’t really take a look as they were an atom.