10,266 research outputs found
A new proton fluence model for E greater than 10 MeV
Researchers describe a new engineering model for the fluence of protons with energies greater than 10 MeV. The data set used is a combination of observations made primarily from the Earth's surface between 1956 and 1963 and observations made from spacecraft in the vicinity of Earth between 1963 and 1985. With this data set we find that the distinction between ordinary proton events and anomalously large proton events made in earlier work disappears. The greater than 10 MeV fluences at 1 AU calculated with the new model are about twice those expected on the basis of models now in use. In contrast to earlier models, results do not depend critically on the fluence from any one event
Chiral molecules split light: Reflection and refraction in a chiral liquid
A light beam changes direction as it enters a liquid at an angle from another
medium, such as air. Should the liquid contain molecules that lack mirror
symmetry, then it has been predicted by Fresnel that the light beam will not
only change direction, but will actually split into two separate beams with a
small difference in the respective angles of refraction. Here we report the
observation of this phenomenon. We also demonstrate that the angle of
reflection does not equal the angle of incidence in a chiral medium. Unlike
conventional optical rotation, which depends on the path-length through the
sample, the reported reflection and refraction phenomena arise within a few
wavelengths at the interface and thereby suggest a new approach to polarimetry
that can be used in microfluidic volumes
Hyperfine Level Splitting for Hydrogen-Like Ions due to Rotation-Spin Coupling
The theoretical aspects of spin-rotation coupling are presented. The approach
is based on the general covariance principle. It is shown that the
gyrogravitational ratio of the bare spin-1/2 and the spin-1 particles is equal
unity. That is why spin couples with rotation as an ordinary angular momentum.
This result is the rigorous substantiation of the cranking model. To observe
the phenomenon, the experiment with hydrogen-like ions in a storage ring is
suggested. It is found that the splitting of the
hyperfine state of the and ions
circulating in the storage ring ESR in Darmstadt along a helical trajectory is
about 4.5 MHz. We argue that such splitting can be experimentally determined by
means of the ionic interferometry.Comment: 6 pages, final versio
Topological phase for entangled two-qubit states and the representation of the SO(3)group
We discuss the representation of the group by two-qubit maximally
entangled states (MES). We analyze the correspondence between and the
set of two-qubit MES which are experimentally realizable. As a result, we offer
a new interpretation of some recently proposed experiments based on MES.
Employing the tools of quantum optics we treat in terms of two-qubit MES some
classical experiments in neutron interferometry, which showed the -phase
accrued by a spin- particle precessing in a magnetic field. By so doing,
we can analyze the extent to which the recently proposed experiments - and
future ones of the same sort - would involve essentially new physical aspects
as compared with those performed in the past. We argue that the proposed
experiments do extend the possibilities for displaying the double connectedness
of , although for that to be the case it results necessary to map
elements of onto physical operations acting on two-level systems.Comment: 25 pages, 9 figure
Fragmentation of explosively metastable glass [post-print]
An unusual form of glass with bulbous head and thin tail, known as Rupert\u27s drops, can withstand high impact or pressure applied to the head, but explodes instantly into small particles when the tail is broken. The mechanism is not well understood. To examine this, we performed macro- and microstatistical analyses of a sample of 500 g of fragments of exploded Rupert\u27s drops to determine the mass and particle distributions and associated fractal dimensions. To our knowledge, this is the first such statistical study of the fragmentation of a metastable material with large internal energy. The resulting fractal dimensionD = 1.06 ± 0.09, derived from the scaling region of the mass and particle distribution functions approximated by power laws, differs from fractal dimensions (usually ≥2) previously reported for many brittle materials. The observed distribution functions place constraints on proposed mechanisms for the explosive disintegration of the drops and presumably other physical systems characterized by high compressive stress at the surface and tensile stress within the core
Compositeness effects, Pauli's principle and entanglement
We analyse some compositeness effects and their relation with entanglement.
We show that the purity of a composite system increases, in the sense of the
expectation values of the deviation operators, with large values of the
entanglement between the components of the system. We also study the validity
of Pauli's principle in composite systems. It is valid within the limits of
application of the approach presented here. We also present an example of two
identical fermions, one of them entangled with a distinguishable particle,
where the exclusion principle cannot be applied. This result can be important
in the description of open systems
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