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Answers from Particle Physics

Unfortunately, such a universe that inflated sufficiently never made a smooth transition to a radiation-dominated, early Friedmann cosmology. In the new inflationary models (1982), the vacuum energy density dominates while the relevant region of the universe inflates and [Pg.53]

On the experimental front, Bias Cabrera claimed the detection of a magnetic monopole on February 14,1982, after 150 days of searching with a superconducting quantum interferometer device (SQUID). If this observation were correct and even approximately corresponded to the typical distribution of monopoles in space, then neither the excessive production of a naive GUT model nor the extreme scarcity of a new inflationary model could be credible. Confirmation of this monopole detection would leave current theory totally at a loss to explain the monopole abundance, but neither Cabrera nor other observers have yet claimed another detection. After more than 3000 days had passed, most workers were of the opinion that the single event was due to something less exotic than a magnetic monopole. [Pg.54]


Ehrenfreund P., et al. (2003). Physics and chemistry of icy particles in the universe answers from microgravity. Planetary and Space Science 51 473-494 Emeline A. V. (2003). Abiogenesis and photo-stimulated heterogeneous reactions in the interstellar medium and on primitive Earth. Relevance to the genesis of life.. Journal of Photochemistry and Photobiology C 3 203. [Pg.330]

Chemical elements are central for the existence of life and the richness and variety of our environment. Therefore, one of the basic questions concerns the origin of the chemical elements. The answer is complex because it relies on dynamical processes from elementary particles and nuclei to stars and galaxies. An interdisciplinary effort of various flelds of science achieved considerable progress in this direction of research. This chapter summarizes the state of knowledge obtained mainly from particle and nuclear physics, astrophysics, and astronomy. [Pg.615]

One basic difficulty with the nonlinear equation arises from the following. Consider a physical situation where a source of particles is composed of many emitters, each emitting a particle at a time. If considered alone, each particle would be described by a localized wave /,- solution of the master equation. Now, what happens if, instead of emitting the particles one by one, the source emits many particles at the same time If the master equation were a linear equation, like the usual Schrodinger equation, the answer would be trivial. The general solution would be simply the sum of all particular solutions. [Pg.511]

Of course, we need to check that the p g) we defined is actually a linear transformation. Here the physics helps us. Recall from Section 1.2 that linear combinations of vectors can be interpreted physically if a beam of particles contains a mixture of orthogonal states, then the probabiUties goverrung experiments with that beam can be predicted from a linear combination of those states. Thus observer A s and observer B s linear combinations must be compatible. In other words, if observer A takes a linear combination ci/i -+ c fi, while observer B takes the same linear combination of the corresponding states cip(g)/i C2p(g )h. the answers should be compatible, i.e.,... [Pg.135]

Answer 2 given above invites, of course, another question Where do the fundamental thermodynamic relation h = h x) and the relation y = y x) come from An attempt to answer this question makes us to climb more and more microscopic levels. The higher we stay on the ladder the more detailed physics enters our discussion of h = h(x) and y = y(x). Moreover, we also note that the higher we are on the ladder, the more of the physics enters into y = y(x) and less into h = h x). Indeed, on the most macroscopic level, i.e., on the level of classical equilibrium thermodynamics sketched in Section 2.1, we have s = s(y) and y y. All the physics enters the fundamental thermodynamic relation s s(t/), and the relation y = y is, of course, completely universal. On the other hand, on the most microscopic level on which states are characterized by positions and velocities of all ( 1023) microscopic particles (see more in Section 2.2.3) the fundamental thermodynamic relation h = h(x) is completely universal (it is the Gibbs entropy expressed in terms of the distribution function of all the particles) and all physics (i.e., all the interactions among particles) enters the relation y = y(x). [Pg.81]

Does the particle nature of light cause its wave aspects Or vice versa All these questions may only be asked from the point of view of classical physics, they only have meaning from the classical view. Once quantum mechanical physics enters the scene, no one even attempts to answer the questions on the classical level, if my guess that brain and mind are parallel aspects of a more fundamental reality is nebulous, perhaps it will take on some relevance when a "quantum mechanics of philosophy" will be available, whether a process of mind studying mind will accomplish such a feat is still an open question. [Pg.92]

The correlation problem thus becomes the following is it jxjssible (and useful) to find a physically significant independent-particle scheme If so, is this satisfactory from the interpretation point of view If the answers to these questions are respectively yes and no, correlation can be both defined and assigned an important role. But as the independent-particle model which satisfied the first question may not be that of Hartree-Fock, the correlation thus defined may have nothing to do with the correlation usually referred to. [Pg.44]

Strictly speaking, the question whether or not the use of an independent-particle model is important is a matter of opinion, because it is certainly not necessary for calcrdating the expectation values of many molecular observables. However, if one looks at the question from the point of view of usefulness in schematization and in general in understanding of physical facts, it seems that there is little doubt about a positive answer. Natural philosophers believe that, in general, simple reference models cannot be dispensed with in the process of understanding the physical world, and a model based on the concept of particle seems to be particularly suitable for that purpose in dealing with atoms and molecules. [Pg.44]

The way in which the iron core in ferritin might build up and the structure of the mineral and its properties have been considered by many researchers over the years and yet there are still many questions that remain to be answered satisfactorily. From one viewpoint the subject belongs in the area of biomineralization, from a different standpoint the nanoscale properties have been of interest, and a third important area of research concerns the health aspects of iron storage and homeostasis. For this latter field the problems of too much or too little are to the fore, with iron overload disease a serious problem in much of Africa and the Middle East while in the Western world iron deficiency is more likely to be a problem. A key aspect to such health problems concerns the response of the organism to local iron levels and is regulated in healthy subjects by an iron response element (IRE) which also seems to involve metalloproteins within the so-called iron response protein. However, this has but little bearing on coordination chemistry aspects of ferritins that we are considering here whereas the chemical questions behind the mineralization processes and the measurement and interpretation of the physical properties of such nanoscale particles are of intense interest. It turns out to be helpful to consider these two aspects in tandem, as one tends to inform the other. [Pg.184]


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Particle physics

Particle physics particles

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