Extracts from the Internet

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Antiproton studies

1 June 1999

As another step in the search for possible particle-antiparticle differences, high precision measurements of the proton's charge- to-mass ratio q/m were carried out at CERN by G Gabrielse and his colleagues. In this experiment, antiprotons produced in the accelerator were slowed down to a very low velocity and directed into an ion trap, after which the bending of their paths by the trap's magnetic field allowed the value of q/m to be obtained. This value was found to be within 9×10^-11 of its proton counterpart, a result which represents about an order-of-magnitude improvement over previous studies. A new proton-antiproton asymmetry, if discovered, would have far-reaching implications for the theory of elementary particles. Source: http://ojps.aip.org/prlo/top.html

Multiple states of Rydberg atoms

1 June 1999

P Bucksbaum, of the University of Michigan, and his colleagues have employed laser pulses of very short duration for placing a highly excited Rydberg atom in many quantum states simultaneously. When absorbed by an atom, such a pulse, a superposition of electromagnetic waves of different frequencies, transforms into a superposition of the quantum states of atomic electrons. In a Rydberg state, an electron is not an `electron cloud' surrounding the nucleus but rather a wavepacket circling the nucleus like a planet around a star. Applying a series of laser pulses can create a number of wavepackets that interfere with each other. The effect is of interest for quantum computer design: even today, several bits of information can already be stored using a single Rydberg atom. Source: Physics News Update, Number 429

Development of roughness in the atomic deposition process

1 June 1999

Dutch research team led by S van Dijken have used copper as an example material to study the formation of roughness during the deposition of atoms on a surface. However smooth a surface may look, the presence of protruding islands of atoms always makes it rough on the atomic scale. These islands affect electrostatically and attract the atoms being deposited, thus increasing the already existing microscopic roughness. The phenomenon has possible applications in novel molecule-sized structures with tailored properties. Source: Physics News Update, Number 428

Distant radio galaxy

1 June 1999

A radio galaxy is a source of powerful radio waves typically generated, by a synchronous mechanism, in two gas clouds, 10 to 100 kpc from the galaxy's centre, that are due to energy release from the galaxy's core. In the course of a systematic search for distant galaxies among ultra-steep spectrum sources, the most distant known galaxy has been discovered using the Keck II telescope. Experience shows that the larger a galaxy's (absolute) spectral index, the higher its luminosity and hence the easier its discovery. Keck II images made in the infrared showed the new galaxy to have an emission line Ly-α shifted towards the IR range because of the expansion of the Universe. The value of the galaxy's redshift is found to be z=5.19. The galaxy's radio emission that now reaches the Earth was produced when the galaxy was no more that one tenth its present age. Source: http://xxx.lanl.gov/abs/astro-ph/9904272

News feed

The Extracts from the Internet is a section of Uspekhi Fizicheskih Nauk (Physics Uspekhi) — the monthly rewiew journal of the current state of the most topical problems in physics and in associated fields. The presented News is devoted to the fundamental discoveries of physics and astrophysics.

Permanent editor is Yu.N. Eroshenko.

It is compiled from a multitude of Internet sources.