Rubidium isotope

ISOTOPES There are 30 isotopes of rubidium, ranging from Rb-75 to Rb-98. Rb-85 is the only stable form of rubidium and constitutes 72.17% of all rubidium isotopes found in the Earth s crust. Rb-87 is radioactive (a half-life of 4.9x10 ° years) and makes up about 27.83% of the remainder of rubidium found in the Earth s crust. All the other 28 isotopes make up a tiny fraction of all the rubidium found on Earth and are radioactive with very short half-lives. 

Rubidium-87 emits beta-particles and decomposes to strontium. The age of some rocks and minerals can be measured by the determination of the ratio of the rubidium isotope to the strontium isotope (see Radioisotopes). The technique has also been studied in dating human artifacts. Rubidium has also been used in photoelectric cells. Rubidium compounds act as catalysts in some oiganic reactions, although the use is mainly restricted to that of a cocatalyst. 

The trough method was employed by Wagener (68) for the separation of the rubidium isotopes in rubidium acetate. The highest enrichment reached (without output) in Rb was 40.8% (natural composition 27% sm). 

Lanphere M. A., Wasserburg G. J., Albee A. L., and Tilton G. R. (1964) Redistribution of strontium and rubidium isotopes during metamorphism, World Beater Complex, Panamint range, Cahfornia. In Isotopic and Cosmic Chemistry (eds. H. Craig, S. L. Miller, and G. J. Wasserburg). North Holland, Amsterdam, pp. 269-320. 

Rubidium-87 is used to estimate the age of very old rocks. Many kinds of rocks contain two rubidium isotopes, rubidium-85 and rubidium-87. When rubidium-87 breaks down in the rock, it changes into a new isotope, strontium-87. Any rock that contains rubidium-87 also contains some strontium-87. 

Abstract The protection of the coherence of open quantum systems against the influence of their environment is a very topical issue. The main features of quantum error-correction are reviewed here. Moreover, an original scheme is proposed which protects a general quantum system from the action of a set of arbitrary uncontrolled unitary evolutions. This method draws its inspiration from ideas of standard error-correction (ancilla adding, coding and decoding) and the Quantum Zeno Effect. A pedagogical demonstration of our method on a simple atomic system, namely a Rubidium isotope, is proposed. 

The paper is organized as follows. In Sec. 1, we introduce the main features of quantum error-correction, and, particularly, we present the already well-developed theory of quantum error-correcting codes. In Sec. 2, we present a multidimensional generalization of the quantum Zeno effect and its application to the protection of the information contained in compound systems. Moreover, we suggest a universal physical implementation of the coding and decoding steps through the non-holonomic control. Finally, in Sec. 3, we focus on the application of our method to a rubidium isotope. 

In this section, we have presented a method which allows one to protect information from a given set of unitary errors. Moreover, we have suggested a physical way to implement the coding and decoding steps, employing the non-holonomic control. In the last section, we propose an application of our method to a real physical system, namely a Rubidium isotope. 

All the isotopes of the lighter cesium homologue in the Periodic System of the Elements, namely rubidium, which are formed by nuclear fission, show short half-lives. Only the longest-lived of them, Rb. can be detected in the primary coolant it is probably generated in the coolant by p decay of its precursor Kr. Because of the short halflives and the comparatively low fission yields, little significance can be attributed to the rubidium isotopes in the coolant. 

The rubidium isotope Rb is radioactive and makes up 27.8% of all natural rubidium. Because of that it is used in the rubidium/strontium technique for dating rocks. 

This little story is mainly about my associations with potassium and rubidium, two elements in the alkali metal series of the periodic table. My Ph.D. thesis at the University of California in Berkeley (1934-1937) was concerned with potassium metabolism in the rat during pregnancy and lactation. In those days nutrition research was the major activity in biochemistry in the United States. In the course of my work I found among other things that the essential element, potassium, could be replaced by rubidium for growth of the rat, although after a time nervous disturbances and other toxic manifestations resulted. Rubidium is, in fact, transported by the same system which tissues use to take up potassium, so that nowadays one often measures potassium uptake activity with the radioactive isotope, Rb. The rubidium isotope happens to have a longer half-life and is more convenient to use than... 

The effect of serum in stimulating the uptake of the rubidium isotope is detectable in only 2 minutes (Fig. 1). The effect is rapidly reversed when serum is removed. It can be... 

See, for example, X. Campi, M. Epherre, Calculation of binding energies and isotope shifts in a long series of rubidium isotopes, Phys. Rev. C22 2605 (1980). 

A detailed study of wall relaxation in pure rubidium isotopes has been made by Mme. Bouchiat and her colleagues (Bouchiat and Brossel 1962, Bouchiat 1963, Bouchiat and Grossetgte 1966). They find that the longitudinal re-... 

Since the ground-state hyperfine levels of a particular rubidium isotope are given by F=I -j, we find that equation (18.24) leads to identical g-values, differing in sign ... 

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