In search of violations

This week high-energy physics published some interesting results for our fundamental knowledge of the universe. On 14th November, LHCb published the preliminar analysis about a possible CP-violation in charm decays (see also the CERN's Bulletin and Mat Charles' presentation).
The researches about CP-violations are very important because in this way we can argue the differences between matter and anti-matter. If a physics law is CP-invariant, we must write that the beahvior of matter and anti-matter is the same. But our universe is constituted by matter and we don't know why it is so. The answer could be in CP-violation studies, like the preliminary data analyzed by LHCb team. The main goal of the experiment is the search of the properties of quark b, but he could also measure the properties of quark c. And studying the preliminary data about c decays the team find a clue of a CP-violation in a non expected channel. Following Tommaso Dorigo and Marco Delmastro (english translation by Google), if the result will be confirmed by further analysis, this could be the first sign of physics beyond Standard Model.
The other possible violation is the wall of the speed of light: indeed, OPERA experiment confirm their previous data. Yesterday, in the updated version of their famous preprint, OPERA's researchers described a new serie of measures realized with CNGS using a short-bunch wide-spacing beam.

The birth of the web

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Tim Berners-Lee In Italy we celebrate the 20th anniversary of the web. Internet was born in the early years of the 20th century at the end of 1980s at CERN. On 13rd March of 20 years ago Tim Berners-Lee (list of publications) with Robert Caillau and others propose a project to construct a scientific world network: the world-wide web.
Berners-Lee is a computer scientist, in particular expert in text editors, real-time software and communications. He is considered the most influencal scientists alive today, and he started to work on hypertextual systems in 1980 developing Enquire, and in 1989 he started the World-Wide Iniziative. Robert Caillau joined it in 1990 and in the next year arrived also Jean-Fran├žois Groff and Bernd Pollerman. The team laid the basis of the modern web with three papers: World-Wide Web: The information universe(6), World-Wide Web: An information infrastructure for high-energy physics(7), World-Wide Web(8).
In the first paper, published in a referred journal, the researchers begin in The Dream section with the following words:
Pick up your pen, mouse, or favorite pointing device and press it on a reference in this document —perhaps to the author's name, or organization, or some related work. Suppose you are then directly presented with the background material —other papers, the author's coordinates, the organization's address, and its entire telephone directory. Suppose each of these documents has the same property of being linked to other original documents all over the world. You would have at your fingertips all you need to know about electronic publishing, highenergy physics, or for that matter, Asian culture. If you are reading this article on paper, you can only dream, but read on.
The construction of Berners-Lee's group dream start in 1945 with the historical paper of Vannevar Bush, As we may think(1) where the american inventor laid the basis to construct a scientists' network through hypertexts. The way towards this system had another founding father, Douglas Engelbart(2). He is also an american inventor, with scandinavian origin, pioneer in the development of graphical user interfaces. And after Bush and Engelbart we arrive to Berners-Lee, Caillau and collegues.
The structure developed by Berners-Lee team is outlined by the following diagram:
From the first definition of the W3 model I would extract the following two points:
  • Indexes are documents, and so may themselves be found by searches and/or following links. An index is represented to the user by a "cover page" that describes the data indexed and the properties of the search engine.
  • The documents in the web do not have to exist as files; they can be "virtual" documents generated by a server in response to a query or document name. They can therefore represent views of databases, or snapshots of changing data (such as the weather forecasts, financial information, etc.).
In some way this structure is the good tools for scientists in order to write and share our papers and discussions in a most simple and complete way. In order to construct an architecture like it it is need develop three key points:
  • a common naming scheme for documents
  • common network access protocols
  • common data formats for hypertext
And these are the three elements that developers try to upgrade in present day.

0.0909090909: Shroedinger's cat

Following Uri Geller (via Peter Woit), today it could be open a portal to another universe!
Geller support his original idea with a mix of string theory and numerology. At the other hand, this mixture of science and superstition is perfect for a fiction, for example The Invisibles, the cult comics written by Grant Morrison in the past century. The comic book series, behind the entertainment pourposes, hides a political purpose, to tell the world and the use of mass media in order to control people. But I don't write about this subject, but about the scientific background, in particular I would start from the many worlds hypothesis(1).
In The Invisibles there is, indeed, a war against alien from another universe. The scientific basis of the comics is the string theory: for example the simbols of early cristians is interpreted like a part of the infinity symbol, that it also represents the connection between the two universes, like two universal strings or two membranes (or branes). But the story of the scientific multiversity began woth the famous Schroedinger's cat: The thought experiment was proposed by Schroedinger in 1935 in order to proof the limits of quantum mechanics and Copenaghen interpretation, but Erwind could not know that his paradox would be generate a lot of intriguing theoretical science. One consequence is the many worlds interpretation, but another research line is the construction of a real Schroedinger's cat!
A first right attempt was made by Jonathan Friedman and collegues(2) (read physicsworld). The team realized a superconducting quantum interference device (SQUID):
The simplest SQUID is a superconducting loop of inductance $L$ broken by a Josephson tunnel junction with capacitance $C$ and critical current $I_c$. In equilibrium, a dissipationless supercurrent can flow around this loop, driven by the difference between the flux that threads the loops and the external flux $\phi_x$ applied to the loop.
They used two junctions in their experimental setup, and so they realized a superposition between two different states:
Such a superposition would manifest itself in an anticrossing, where the energy-level diagram of two levels of different fluxoid states (labelled $| 0 >$ and $| 1 >$) is shown in the neighbourhood in which they would become degenerate without coherent interaction (dashed lines). Coherent tunnelling lifts the degeneracy (solid lines) so that at the degeneracy point the energy eigenstates are \[\frac{1}{2} \left ( | 0 > + | 1 > \right )\] and \[\frac{1}{2} \left ( | 0 > - | 1 > \right ) \, ,\] the symmetric and anti-symmetric superpositions. The energy difference $E$ between the two states is given approximately by $E = \epsilon^2 + \Delta^2$, where $\Delta$ is known as the tunnel splitting.
In order to proof the existence of the splitting, a necessary condition is that:
(...) the experimental linewidth of the states be smaller than $\Delta$(3). The SQUID is extremely sensitive to external noise and dissipation (including that due to the measurement of ), both of which broaden the linewidth. Thus, the experimental challenges to observing coherent tunnelling are severe. The measurement apparatus must be weakly coupled to the system to preserve coherence, while the signal strength must be sufficiently large to resolve the closely spaced levels. In addition, the system must be well shielded from external noise. These challenges have frustrated previous attempts5, 6 to observe coherence in SQUIDs.
But the observation presents some difficulties, like the SQUID's sensibility to the noise, which must be shielded, and to the dissipation; the device must also preserve the coherence,
(...) while the signal strength must be sufficiently large to resolve the closely spaced levels.
All of these problems influenced previous attempts(4, 5), but they found an answer thanks Friedman's team:
In the plot it is showed the probability to realize a transition like function of the flux $\phi_x$. The curves, plotted for different potentials, are shifted upwards in order to clarify the shapes. The quantum behaviour of the macroscopic system is argued by the existence of two peaks, that decreasing potential separate one from each other and reach the same amplitude. The two peaks correspond to two distinct macroscopic fluxes and we can conclude that they realize a macroscopic Schroedinger's cat.
A most recent attempt has made this year (via tumblr) by a team of China's researchers leaded by Xing-Can Yao(6). The team, using the following experimental setup:

Laika: a comics about a hero

Laika was the first living being to go in space. Its adventure was written by Rick Abadzis in a beautiful graphic novel, that I read two years ago.
The story began with Sputnik 1, the first russian space mission launched in space on October 4, 1957, in order to send a signal to Earth. The next mission, Sputnik 2, launched on November 3, 1957 with the first living thing on board, a dog, Laika. This second mission, however, arose under pressure from the government, which would celebrate the fortieth anniversary of the October revolution with a new, great success of the spatial plan of the Soviet Union. So the mission was prepared in haste, designing a less sophisticated satellite than Sputnik 1 that was not expected it would be back on the planet: a death sentence beyond a reasonable doubt for his passenger. Laika's death, however, was very early: the mission was designed to last a week or less, but the dog died long before, in 5-7 hours:
The fact, that pressure in the cabin was not reduced, proved its reliable tightness. It was very important, as the satellite passed through areas of meteoric flows. Normalization of parameters of breath and blood circulation of Layka during orbital flight has allowed to make a conclusion, that the long weightlessness does not cause essential changes in a status of animal organisms. During flight the gradual increase of temperature and humidity in the cabin was registered via telemetric channels. Approximately in 5 - 7 hours of flight there was a failure of telemetry system. It was not possible to detect a status of the dog since the fourth circuit. During the ground simulation of this flight's conditions, the conclusion was made, that Layka should be lost because of overheating on 3d or 4-th circuit of flight.(1)
So, the hypothesis of silence imposed from above on the health conditions of Laika, or more than anything else on the impossibility to monitor them, told by Abadzis are not so far-fetched: we must consider, in fact, that the animal (in the government vision) would had to stay alive in time to celebrate the forty years of the October Revolution!
And the British cartoonist tells not only the historical background of Laika's story, but also the simple story of a dog that goes in space from the street and the story of the people who shared their life and love with the little dog.
A graphic novel, made with the classic bd style, that you can not miss in your collection.
(1) Dmitrij Malashenkov, Some Unknown Pages of the Living Organisms' First Orbital Flight