February 2, 2012 10:59
Physicists have created the universe out of the atom
On the example of the potassium atom created a model of interaction with its Jupiter Trojan asteroids
An international team of physicists has made from the electron so that it began to behave as an object whose movement is subject to the laws of classical mechanics. Thus they have the example of the potassium atom model of the interaction of Jupiter with its Trojan asteroids. And also proved the validity of the hypothesis is quite old Niels Bohr …
Early last century, Ernest Rutherford, offering its product model of the atom, said that, in principle, the structure of this unit of the universe is very similar to that of an abstract of the planetary system. Like, in the center of the atom is the nucleus, which is similar to the star, and next to it the standard orbits like planets orbit electrons. From this statement, followed by a very interesting conclusion — the laws of functioning of planetary systems can be studied as an example of an atom. That, as you know, is much simpler than a thousand telescopes to watch.
Unfortunately, however, soon this model was abandoned because there was one insoluble contradiction. The fact that, according to classical electrodynamics, the electron motion with the centripetal acceleration must emit electromagnetic waves, and therefore lose energy. Well, it is, you know, of course — that is, as a result of an electron just fall into the nucleus. And the time for which a complete loss of power occurs, it can be said, it is insignificant — it is some hundredths of a second.
As a result, scientists realized that the motion of the electron around the nucleus does not obey the laws of classical mechanics. I had to create a completely new area of scientific knowledge — quantum mechanics, which gave answers to many questions. So now even high school students are aware of that going around the nucleus, the electron loses energy, that certainty in its trajectory is no, and that you can only talk about the probability of finding the electron at a given point at a given point near the nucleus.
In general, the state of the electrons is described by a wave function, which characterizes the square modulus of the probability density of finding the particle at a given point in a given time. Simply put, the scientists believe that the electrons as if smeared around the nucleus. Accordingly, physicists may never know exactly where a particular point is a specific electron — they can only speculate about the likelihood of their presence in a particular place.
It turns out that the atom can not be a model of the planetary system — because the trajectory of the planets quite clear, and where at any one time is one time or another celestial body, you can always say definitely. However, scientists still sometimes visits the desire to turn an atom in a similar model. And, most interestingly, in some cases, they succeed.
In principle, such do not so difficult. First of all, you need some way to collapse the wave function of an electron, causing the particle to behave as a localized wave packet (figuratively speaking, "shrink to the point"). And, of course, you should make it so that the entire system, that is, the electron and the nucleus is not destroyed (and then there will be nothing to watch.)
One of the authors' graduate student Shuzhen E (Shuzhen Ye) (Photo Jeff Fitlow / Rice University).
And recently, scientists from Rice University (USA), Vienna University of Technology and the U.S. Oak Ridge National Laboratory were able to conduct a similar experiment with an atom of potassium. Above all, they transferred him to a condition called Rydberg atom — is an atom (hydrogen or alkali metal, with the rest of these "jokes" are not), in which the outer electron is in a highly excited state. Usually, this effect is achieved by irradiation of atoms by resonant laser light or the initiation of radio-frequency discharge. In this case, physicists have selected the first option.
As a result, they were able to collapse the wave function, which is why in the "photos" this electron was like a body that resembles a comma. But here's the problem — when such action is destroyed quickly enough the atom itself. Then the experimenters attached to atom rotating radio frequency electric field. And it has brought success — it captures an electron, and the comma and made him simultaneously revolve around the nucleus. At the same time, the other attached to the system led to an electrical pulse instantaneous "snapshot" of the Rydberg atom.
Once there were several tens of thousands of shots (one was impossible to avoid, because, unfortunately, at the time of photography atom is destroyed), the researchers analyzed the results of the experiment. And what was their surprise when they saw that the localized electron behave in relation to the nucleus as well as … Trojan moons of Jupiter!
Recall that the Trojan satellites commonly called celestial bodies (eg, asteroids), in the vicinity of the Lagrange points L4 and L5 (the point at which they are fixed relative to the nearest celestial bodies) in a 1:1 orbital resonance of any planets. And, by the way, of Jupiter, "Trojans" a lot — more than four thousand. And here they are, according to the observations of astronomers, as well, in orbit of Jupiter, together form two "commas" (in the form similar to the localized wave packet) that are ahead of this gas giant and behind the planet in its path around the Sun.
"Even Niels Bohr predicted that quantum-mechanical description of the physical world for systems of sufficient size will be the same as the classical description presented Newtonian mechanics. He also pointed out the conditions under which this correspondence could be observed. In particular, such a coincidence should be seen in atoms with very high principal quantum number "- sums up the experiment Dr. Barry Dunning, who led the team of researchers.
Interestingly, it was confirmed this prediction and physics in this experiment. Principal quantum number of the electron in a Rydberg atom in these experiments ranged from 300 to 600 (note that the principal quantum number describes the energy level of the electron). "In such excited states, the potassium atoms in the hundreds of thousands of times greater than normal, and are like the size of the dot at the end of the sentence. Thus, they are good candidates for testing the predictions of Bohr, "- says Professor Dunning.
So, as you can see, in fact, under certain conditions, may be a microcosm in the macrocosm as a model. However, this is not the limit. In the future, the authors of this paper want to locate just two electrons. Let them run around the nucleus, as the two planets around the sun …