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The three families of elementary particles and the arrow of time

Perhaps most intriguing fact in the world of elementary particles is the existence of three and only three families. The first is made up of quarks up and down with the electron and electron-neutrino. The same structure is repeated with the charm quarks and strange in the company of the muon and muon neutrino. The third replica lies with the family made up of top quarks and bottom, with the tauon and tau neutrino. Why

nature offers three replicates the same structure? This is a question of great depth and it questions the ultimate structure of the Standard Model of electroweak interactions. However, there is an observation that can not leave us indifferent. In the Standard Model is only possible to have violation of T (time reversal) if three or more families.

The T symmetry violation is an event truly exceptional. Implies that there are physical processes that can discriminate between it moves in one direction or the opposite. This violation of T, due to the presence of three families of elementary particles, is the only situation in which the laws governing the universe at the microscopic level selected arrow of time.

arrow Do not confuse this time with the second law of thermodynamics, which states what is the most likely development of a system of many particles. The thermodynamic irreversibility does not require a microscopic T violation.

The universe, therefore, opted to contain three and only three families of elementary particles and thus offer the option to distinguish between it moves in one direction or its opposite.

Monopoly Boutique Edition

The speed of light

The study of the speed of light is a fascinating and subtle issue that gives rise to a thousand questions.

1) "I can measure the speed of light?
No. The emergence of special relativity (and the fact that the constancy of the speed of light in any inertial reference system is a second postulate) has led to a change in the way they define the fundamental units. Today, the meter is defined com the way light travels in 1 / 299792458 s. The second is defined by an atomic transition frequency (which is a standard that is already obsolete given the new watches "source" with precision measurements of time which is at around 10 ^ {-16} s). Measuring the speed of light is therefore a tautology since the meter must first be defined using the propagation of photons. In short, the speed of light c = 299792458 m / s is a definition, has no error because there is an observation. Someday

choose to define the unit of energy (mass) using a definition of hbarra, Planck's constant. This completes a remarkable fact. Newton's equation, F = ma, you have three variables to its right, time, length and mass. Simply define and apply two relationships. That would be c hbarra. It is extremely elegant.

2) What underlies the concept of the speed of light?
Causality. Photons and any massless particle propagating c. This is the maximum transmission speed of any signal. For Thus, implementing "causality." Causality has to do with the cause precedes the effect, but more refined means the action of energy deposited in a remote place. It's an idea sometimes confusing. Causality is associated with a cause do work elsewhere.

3) Does it violate causality the collapse of the wave function in quantum mechanics?
No. A measure gives us an immediate, information on the entire system. This does not mean to send a message immediately, or take action in a way that violates causality. For example, return from a trip to China, I open my suitcase and I have a black sock decoupled. I know in China another black sock. My information has been accurately instantly, has collapsed. But there is no photon transport or signs, no remote actions.

4) "Mathematically, what is the speed of light?
The propagator of a photon has a singularity on the light cone, which is defined by c ^ 2 t ^ 2 - (\\ vec x) ^ 2 = 0. This relationship follows from the Poincaré invariance. All Poincare invariant theory with massless propagators have the same light cone and, therefore, traveling acy define causality. For a variation of c, Poincaré symmetry is violated.

5) Can violate the Poincare symmetry? Yes, there
conditions that violate this symmetry. A photon can travel in a curved space. Poincare symmetry is valid only locally (Einstein's equivalence principle). In geodesic space of curvature not zero, the photons define causality, but not travel to c. You may have other violations of Poincare symmetry with plates, Casimir effect or factual description of thermal baths or areas filled with electromagnetic fields.
(There is a world power behind the concept of time travel in space with worm holes and Hawking's idea to propose a principle of protection chronological order.)

6) Can you measure a variation of the speed of light?
is incredibly difficult. This would have, for example, the same experiment without license plates and the Casimir effect and see a difference. This can be done for the Casimir energy. The problem is that the effect is typically E / m ^ 4, where E is the vacuum energy difference m the electron mass. For example take the case thermal E \\ sim T ^ 4. The effect inside the Sun is suppressed by forty orders of magnitude.

7) I have read that has been transmitted signals v> c. Is it right?
Experiments bearing the seal of supralumínica speed are somewhat misleading. In these experiments, wave packets are sent as group velocity exceeds c. It is advertised as cumbersome. However, the wave packet of the higher frequency always travels at c. Are the precursors (Forerunners) to begin laying energy. Nothing in violation of the Poincaré symmetry, c is constant. Other speeds in a package, the com phase velocity, it is not associated with energy transport and is not subject to any restrictions.


A photon coming from a quasar at the edge of the universe must obey these laws so unflappable during 10 ^ 17 seconds.

Milena Velba On Bus Adult

Pärt and Glass

Two composers I am attracted by their different way of trying to survive over time.

The first is Philip Glass. His media image is consistent with their prolific output. At times his insistent use of the same resources I am disappointed. Further, his music is subtle, involves and encourages me to travel. Do not you think you hear some of his pieces on the piano or the soundtrack of "The Hours" is an intimate act?

The second composer Glass is inimical to Arvo Pärt. Religious music touches your silence. "Für Alina" or "My heart is in the Highlands" are contained, introspective. Again, it requests the complicity the listener. Neither Glass nor

auditions Pärt are simple. Some pieces like "Koyaanisqatsi" or "Fratres" are immediately appealing, but its assessment progresses over time. That evolution does not cease in our brain holds the key to longevity. Both composers will grow over time because they did not write for the moment.

P.e.d. Connectorsh-19

The peregrine falcon

The accuracy of the written word has hypnotic power:

"When torque bat torque is excessive, when satisfies the hunger, will soon, when attacked, damaged, when it strikes, cleave, and when you prey gets tired. "

I owe this perfect phrase for translation of a treaty hunting Arabic. That's so brilliant, deadly and treacherous mentioned, that beating, splits and goes quickly, is the gyrfalcon. The quoted phrase is at the very center of the book, and I like to think that's his secret swing.

falconry

The treaty is a written excuse for the Frenchman Pierre Michon create a superb phrase, center and culmination of your essay. His praise is concise and elegant. No more words are necessary.

The image of a gyrfalcon is magnificent in itself and leads me to another of a peregrine falcon. I imagine their movements. Few, electrical. The hawk appears in the gloved hand of a central European noble on a visit to an American lady does. The triangle is completed by an alcoholic husband, jealous of the brutal descent that the bird has on its owner. This triangle is superimposed on the set of ambiguities in the maid with her husband and the driver of the visitors. A third triangle involving the narrator, the ubiquitous host and a hawk. The overlap of the frames is subtle.

Michon's book arouses intellectual curiosity, that of Glenway Wescott is magic. I close with a quotation for this latest work:

Humanity tends to histrionics, worrying about trying to detail every outburst of passion, so that half of our life is a diffuse and stormy fiction.