bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure of Fe-Si-melts by X-ray Diffraction
Authors: Sedelmeyer B. , Steeb S. 
Published: February 2015

Abstract
X-ray diffraction was done with molten Fe66,7 Si33,3 and molten Fe33,3 Si66,7 . The coordination numbers versus the concentration lie above the connection line between the coordination numbers of the unalloyed molten elements Fe and Si, respectively, which means a tendency for microsegregation. The pair correlation function of molten Fe66,7 Si33,3 was modeled using the data of crystalline Fe2 Si. At the same time, the pair correlation function of the molten alloy Fe33,3 Si66,7 can be modeled using the data of the corresponding crystalline alloy. Thus for molten Fe33,3 Si66,7 microsegregation into FeSi2 and Si or FeSi and for molten Fe66,7 Si33,3 microsegregation into Fe2 Si and Fe or FeSi exists.
Helium Atom Scattering from Cyclopentane, Pyrrolidine and Tetrahydrofurane in Crossed Molecular Beams
Authors: Gebauer Christian , Klein Olaf , Schmidt Ralf , Seidel Wolfhart 
Published: February 2015

Abstract
Scattering of helium atoms by cyclopentane, pyrrolidine and tetrahydrofurane molecules was ob-served in crossed molecular beam experiments. The intensity of scattered helium atoms, depending on the scattering angle, was measured with high resolution, and the damping of the diffraction oscillations of the differential cross sections was used to extract elastic anisotropic interaction potentials for these molecules. The evaluation included a geometric transformation concerning the puckered states of the envelope and the twisted conformation of the molecules. The potentials were found to be rather similar.
Photoconductivity of an Anthracene / 2,2,4,4-Tetramethylpentane Solution: Pressure Effect on the Photoionization of Solute and Solvent
Authors: Katoh Ryuzi , Lacmann Klaus , Schmidt F. 
Published: February 2015

Abstract
The photoconductivity spectrum of a solution of anthracene (AN) in 2,2,4,4-tetramethylpentane (TMP) was measured as a function of pressure up to 2 kbar. The threshold energies of photoionization of the solute (AN) and of the solvent (TMP) increase with pressure. The relative quantum yield for charge carrier generation decreased with increasing pressure. The concomitant reduction of the initial separation distance of the geminate charge carrier pairs may be due to an increase of the number of inelastic collisions caused by the increased density of the liquid within the sphere of Coulomb attraction of the positive ion.
Internal Mobilities in the Molten Binary Systems (Tl, K)NO3 and (Tl, Cs)NO3
Authors: Chou P.-H. , Okada I. 
Published: February 2015

Abstract
Ratios of internal cation mobilities in the molten binary systems (Tl, K)NO a and (Tl, Cs)NO3 have been measured by the Klemm method. From these and the data available on the densities and electric conductivities, the internal mobilities b have been calculated. While generally in the mixtures of TlNO3 with alkali nitrates at constant temperature the conductivities and internal mobilities decrease with increasing molar volume, in (Tl, K)NO3 they decrease with decreasing molar volume. This is explained by the high polarizability of the Tl + ions.
Quantum Mechanics as a Generalization of Nambu Dynamics to the Weyl-Wigner Formalism
Authors: Bialynicki-Birula Iwo , Morrison P.J. 
Published: February 2015

Abstract
It is shown that Nambu dynamics can be generalized to any number of dimensions by replacing the 0(3) algebra, a prominent feature of Nambu's formulation, by an arbitrary Lie algebra. For the infinite dimensional algebra of rotations in phase space one obtains quantum mechanics in the Weyl-Wigner representation from the generalized Nambu dynamics. Also, this formulation can be cast into a canonical Hamiltonian form by a natural choice of canonically conjugate variables.
Time Reversal Symmetry and Humpty-Dumpty
Authors: Englert Berthold-Georg 
Published: February 2015

Abstract
It is argued that the quantal evolution of a physical system is fundamentally irreversible although the dynamical equations are symmetric under time reversal. The example of spin coherence in a Stern-Gerlach interferometer demonstrates that even undoing the evolution partially only may require sub-microscopic precision in controlling a macroscopic apparatus.
Is There a Preferred Canonical Quantum Gauge?
Authors: Aharonov Y. , Anandan J. 
Published: February 2015

Abstract
The interaction between a long solenoid and a quantized charged particle in the field free region outside it is studied treating both systems quantum mechanically. This leads to a paradox which suggests that when the electromagnetic field is quantized, there may be a preferred quantum gauge for the vector potential. This paradox is resolved by canonically quantizing the system in a different gauge in which the classical Lagrangian contains an acceleration dependent term.
From Poincare's Divergences to Quantum Mechanics with Broken Time Symmetry
Authors: Prigogine Ilya 
Published: February 2015

Abstract
We discuss the spectral property of unstable dynamical systems in both classical and quantum mechanics. An important class of unstable dynamical systems corresponds to the Large Poincare Systems (LPS). Conventional perturbation technique leads then to divergences. We introduce methods for the elimination of Poincare divergences to obtain a solution of the spectral problem analytic in the coupling constant. To do so, we have to enlarge the class of permissible transformations, to include non-unitary transformations as well as to extend the Hilbert space. A simple example refers to the Friedrichs model, which was studied independently by George Sudarshan and his co-workers. However, our main interest is the irreducible representations in the Liouville space. In these representations the central quantity is the density matrix, and the eigenfunctions of the Liouville operator cannot be expressed in terms of the wave functions. We suggest that this situation corresponds to quantum chaos. Indeed, classical chaos does not mean that Newton's equation becomes "wrong" but that trajectories loose their operational meaning. Similarly, whenever we have an irreducible representation in the Liouville space this means that the wave function description looses its operational meaning. Additional statistical features appear. A simple example corresponds to persistent interactions in the scattering problem which cannot be treated in the frame of usual S-matrix theory.
Uncertainty Relation: From Inequality to Equality
Authors: Süssmann Georg 
Published: February 2015

Abstract
The uncertainty area δ (p, q): - [∫ W(p, q)2 dp dq] - 1 is proposed in place of δ p • δ q, and it is shown that each pure quantum state is a minimum uncertainty state in this sense: δ (p, q) = 2 π ħ. For mixed states, on the other hand, δ(p, q) > 2π ħ. In a phase space of 2F(=6N) dimensions, S: = k B • log[δF (p,q)/(2 π ħ)F] whit δF (p,q):= [∫ W(p, q)2 dF p dF q]-1 is considered as an alternative to von Neumann`s entropy S̃:= kB • trc [ρ̂ log (ρ̂-1)].
Quantum Irreversibility and Chaos
Authors: West Bruce J. , Grigolini Paolo , Bonci Luca , Roncaglia Roberto 
Published: February 2015

Abstract
Herein we establish a relation between quantum irreversibility and the chaotic semi-classical solutions for a spin-boson Hamiltonian system. We obtain quantum averages by numerically integrating the appropriate Liouville-Von Neumann equations of motion and find these averages to be less erratic than the corresponding chaotic semi-classical trajectories. However, the quantum averages are shown to be dissipative as measured by the entropy of the spin subsystem and to suppress the phenomenon of "revivals".
Understanding the q-Factors in Quantum Group Symmetry
Authors: Biedenharnf L. C. , Rao K. Srinivasa 
Published: February 2015

Abstract
A characteristic feature of quantum groups is the occurrence of q-factors (factors of the form qk, k ∈ ℝ), which implement braiding symmetry. We show how the q-factors in matrix elements of elementary q-tensor operators (for all Uq(n)) may be evaluated, without explicit calculation, directly from structural symmetry properties.
Detection of Laser Induced Gratings via Acoustic Enhancement
Authors: Black Truman D. , Larson Don A. 
Published: February 2015

Abstract
Using acoustic wave intermodulation, laser induced grating structures can be detected with enhanced sensitivity. Gratings with phase variations of the order of a few ^irad or displacement gratings of the order of 10 " 1 r m can be detected. The basic spatial frequency analysis explaining this detection enhancement is developed briefly in this paper.
The Dressed State Picture in Quantum Coherence and Interference
Authors: Keitel C.H. , Doss H . M . , Fleischhauer M. , Narducci L.M. , Scully M.O. , Zhu Shi-Yao 
Published: February 2015

Abstract
We investigate the advantageous description of driven multi-level systems in the dressed state representation. A demonstration is given for the cases of subnatural line narrowing and lasing without inversion.
Laser Linac Using a Lens Waveguide in Vacuum
Authors: Moore G. , Bochove E. , Scully M.O. 
Published: February 2015

Abstract
Acceleration of a relativistic electron beam by the longitudinal field component of a focused laser or microwave beam is optimal when the laser beam is radially polarized. The electron energy gain between focusing optical lenses with an arbitrary optical mode cannot greatly exceed that available from a Gaussian beam of the same power. Off-axis transverse forces focus and recollimate appropriately phased off-axis electrons over the acceleration length.
Sudarshan-Glauber P, Q, and Wigner W Distributions in Correlated-Spontaneous-Emission Lasers
Authors: Scully M.O. , Zhu Shi-Yao 
Published: February 2015

Abstract
A comparative study of Sudarshan-Glauber P, Q and Wigner distributions in correlated-spontaneous-emission lasers has been made. Immediately giving the information of squeezing by exam-ining the diffusion coefficients is the advantage of the Sudarshan-Glauber P representation.
Quantum Optics with Trapped Ions
Authors: Raizen M. G. 
Published: February 2015

Abstract
The ability to localize a small number of atoms, with each one moving much less than an optical wavelength (the Lamb-Dicke regime) is a prerequisite for a wide range of fundamental atom-field experiments. Recent developments in ion trapping technology, relevant to this goal, are discussed and some possible experimental directions are outlined.
Self-Duality Condition and Critical Potentials
Authors: Cronström C. , Srivastava Prem P. , Tanaka K. 
Published: February 2015

Abstract
It is shown that the self-duality constraint on the scalar field (combined with the equations of motion) by itself leads to the critical forms for the potential that minimizes the energy functional in the Chern-Simons-Higgs (CSH) system. If we have only the Chern-Simons (CS) term in the SL (2, R) gauge group one obtains a formalism that yields the equations of motion of a variety on non-linear models in two dimensions when the curvature is set equal to zero.
Whither the Anyon ?
Authors: Hägen C. R. 
Published: February 2015

Abstract
It is pointed out that Chern-Simons field theories do not always allow an interpretation in terms of anyons even in the nonrelativistic limit. Significantly, when the two approaches are found to differ the former is the one which is compatible with established physical principles. Thus the role left for the anyon is that of a very special subcase of Chern-Simons theories in the limit in which relativistic and spin considerations become irrelevant.
Planck Scale Physics and Newton's Ultimate Object Conjecture
Authors: Winterberg F. 
Published: February 2015

Abstract
According to Newton, the ultimate building blocks of matter are hard frictionless spheres. This conjecture is here analyzed under different assumptions, which are:
1. The ultimate objects of matter are frictionless positive and negative Planck mass particles obeying nonrelativistic Newtonian mechanics.
2. The Planck mass particles interact with the Planck force c 4 /G (c velocity of light, G Newton's constant) locally within a Planck length r p , with the positive Planck mass particles exerting a repulsive and the negative Planck mass particles an attractive force.
3. Space if filled with an equal number of positive and negative Planck mass particles, whereby in the average each Planck length volume occupies one Planck mass particle.
Making these three assumptions we derive:
1. Nonrelativistic quantum mechanics as an approximation with departures from this approxima-tion suppressed by the Planck length.
2. Lorentz invariance as a dynamic symmetry for energies small compared to the Plank energy.
3. The operator field equation for the previously proposed Planck aether model of a unified theory of elementary particles.
In contrast to theories in which the ultimate objects are strings at the Planck scale, the alternative theory proposed here does not need a higher dimensional space, but rather can be formulated in 3 + 1 dimensions.
NMR Study of Collective Motions and Bending Rigidity in Multilamellar System of Lipid and Surfactant Bilayers
Authors: Struppe J. , Noack F. , Klose G. 
Published: February 2015

Abstract
The frequency dependence of the longitudinal proton spin relaxation time T1 was measured by field-cycling and standard NMR techniques at different temperatures in the liquid crystalline lamellar phases of bilayer systems, composed of lipids, nonionic surfactants, and lipid-surfactant mixtures. We show by our data analysis, comparing various motional models such as layer undulations (LUs) and relaxation by translational diffusion mediated reorientations (TR), that collective layer undulations with their typical T1~ν behaviour determine the low frequency T1 dispersion in both unoriented and glass plate-oriented bilayer systems. The angular dependence of the T1 dispersion for the oriented bilayer system supports these findings and provides a more critical analysis of the two dimensional self-diffusion than in unoriented samples. The evaluated fitting parameters of the LU model allows, together with the measured second moment of the proton NMR signal for the lipid, calculation of the bending rigidity ϰc for these bilayers at different levels of hydration. The obtained values of ϰc turn out to be too large compared with the literature. However, using recent LU models (B. Halle) which include the obvious couplings between neighbouring bilayers at low Larmor frequencies, the corrected ϰc of the fully hydrated membrane systems are comparable to those obtained from the standard videooptical experiments. Therefore proton spin relaxation measure-ments at low Larmor frequencies with the field-cycling technique are a suitable means to determine the bending rigidity ϰc of model membrane systems at low hydrations and of systems containing surfactants.
Helium Atom Scattering from C2H6, F2HCCH3, F3CCH2F and C2F6 in Crossed Molecular Beams
Authors: Hammer Markus , Seidel Wolfhart 
Published: February 2015

Abstract
Rotationally unresolved differential cross sections were measured in crossed molecular beam experiments by scattering Helium atoms from Ethane, 1,1-Difluoroethane, 1,1,1,2-Tetrafluoroethane and Hexafluoroethane. The damping of observed diffraction oscillations was used to extract anisotropic interaction potentials for these scattering systems applying the infinite order sudden approximation (IOSA). Binary macroscopic parameters such as second heterogeneous virial coefficients and the coefficients of diffusion and viscosity were computed from these potentials and compared to results from macroscopic experiments.
Radiative Lifetimes of The Perturbed 6snf3 F3 , 1F3 , and 3F4 Rydberg Sequences of Barium
Authors: Zaki Ewiss M. A. 
Published: February 2015

Extensive new results for the natural radiative lifetimes of the perturbed odd-parity 6snf 3F3, 1F3, and 3F4 sequences of barium (with 11 < n < 40, 11 < n < 40 and 13 < n < 40, respectively) have been calculated. The calculations were performed in the framework of multichannel quantum defect theory. The contributions to the transition probabilities of all known even-parity levels of the 6snd and 6sng configurations together with their perturber states and connected via the electric dipole operator with the 6snf 3F, 1F3, and 3F4 levels, are considered.
The results for the 6snf 1F3 and 3F4 sequences, in contrast with those for the 6snf 3F3 series, show strong deviation from a hydrogenic scaling law. This deviation reflects the extended perturbations of these levels by some of the doubly excited states of the same parity.
The Square Root Approximation to the Dispersion Relation of the Axially-symmetric Electron Wave on a Cylindrical Plasma
Authors: Babović V.M. , Aničin B.A. , Davidović D. M. 
Published: February 2015

Abstract
This paper suggests the use of a simple square root approximation to the dispersion relation of axially-symmetric electron surface waves on cylindrical plasmas. The point is not merely to substitute the exact expression for the dispersion relation which involves a number of Bessel functions with a more tractable analytical approximant, but to cast the dispersion relation in a form useful in the comparison with other waves, such as water surface gravity waves and the associated tide-rip effect. The square root form of the dispersion relation is also of help in the analysis of surfactron plasmas, as it directly predicts a linear roll-off of electron density in the discharge.
Dilatometric Studies Across the Isotropic to Smectic-F Transition
Authors: Srinivasulu M. , Potukuchi D. M. , Pisipati V. G. K. M. 
Published: February 2015

Abstract
Thermal Microscopy (TM), Differential Scanning Calorimetry (DSC) and dilatometric studies were carried out to characterise the liquid crystalline phases and mesomorphic transitions exhibited by three higher homologues of N-(p-n-dodecyloxy benzylidene)p-n-alkyl anilines, viz., N-(p-n-dodecyloxy benzylidene)p-n-dodecyl aniline, (12O.12), N-(p-n-dodecyloxy benzylidene)p-n-tetradecyl aniline, (12O.14) and (N-(p-n-dodecyloxy benzylidene)p-n-hexadecyl aniline, (12O.16). The three com-pounds exhibit enantiotropic smectic-F and smectic-G liquid crystalline phases between the isotropic liquid and the solid crystal. The change in density across the phase transformations and the thermal expansion coefficient confirm the first order nature of the isotropic to smectic-F (I-SmF) and smectic-F to smectic-G (SmF-SmG) transitions. The dilatometric studies infer strong pre-transitional fluctuations in a relatively large thermal range. The pre-transitional effects are estimated by αeff in the vicinity of the mesomorphic fluctuation-dominated non-linear region (FDNLR) of the I-SmF transition. The strength of non linear growth of density fluctuations is discussed in the wake of reports at the I-N, I-SmA and I-SmC transitions.
Quantum Constraints in π Systems: The Role of the Pauli Antisymmetry Principle for π Electronic Properties
Authors: Böhm Michael C. , Schütt Johannes 
Published: February 2015

Abstract
It is demonstrated that the Pauli antisymmetry principle (PAP) is without influence in the π electron subspace of polyenes and (4n + 2) annulenes (n = 0, 1, 2...) as long as the hoppings are restricted to nearest-neighbour centers. Here the π electrons behave like a hard core bosonic (hcb) ensemble where fermionic on-site and bosonic intersite properties are combined. In 4n and (2n + 1) annulenes (n = 1,2, 3...) π electron jumps between the first and last ring atom lead to a Pauli antisymmetry-based destabilization. The second quantum constraint in fermionic systems is the Pauli exclusion principle (PEP). In the many-electron basis adopted in the present work it is possible to treat the PAP and PEP as two decoupled constraints. The electronic destabilization due to the PEP is enhanced with increasing size of the system. The influence of the PAP and PEP on the π electrons is discussed in terms of π energies and charge fluctuations. The model Hamiltonians adopted are of the Hückel molecular orbital (HMO) and Pariser-Parr-Pople (PPP) type. We suggest quantum statistical definitions of the quantities "aromaticity" and "antiaromaticity", qualitative descriptors which are widely employed in the chemical literature.
On the Role of the Pauli Antisymmetry Principle in Pericyclic Reactions
Authors: Böhm Michael C. , Schütt Johannes 
Published: February 2015

Abstract
In the present work we discuss the role of the Pauli antisymmetry principle (PAP) in synchronous pericyclic reactions. These reactions are allowed in the electronic ground state whenever the PAP does not act as a quantum constraint in the transition state. The possible suppression of the influence of the PAP is a peculiarity of π electron systems. The PAP is a hidden (= deactivated) variable in the π electron subspace of polyenes and (4n + 2) annulenes (n = 0, 1, 2,...). In 4n annulenes (n = 1, 2, 3,...) it leads to minority signs in the kinetic hopping matrix of the π electronic wave function and thus to an energetic destabilization. The quantum statistical difference between the above families of π systems renders possible a microscopical definition of the quantities “aromaticity” and “antiaromaticity”. The sign behaviour of the kinetic hopping elements is used in the discussion of pericyclic reactions. The present quantum statistical description of these reactions is related to the Dewar-Zimmermann and Woodward-Hoffmann rules.
EPR Study of VO2+ and Cr3+ in Li2SO4 · H2O Single Crystal
Authors: Çelik F. , Köksal F. , Kartal İ. , Gümüş H. 
Published: February 2015

Abstract
A single crystal X-band EPR study of VO2+ and Cr3+ in Li2SO4 • H2O was carried out at room temperature. Analysis of the spectra indicates that VO2+ substitutes for Li+ and that there are two magnetically inequivalent Li+ sites. The charge compensation occurs by removal of a neighboring Li+ . The principal values of the g and A tensors of the spin Hamiltonian for the two sites were determined. Superhyperfine interaction of the 3d1 electron of VO2+ with the neighboring water protons in the unit cell was observed and found to be between 0 and 0.5 mT, depending on the orientation of the magnetic field. Two magnetically different sites were also observed for Cr3+ , and the results were explained by a rhombic spin Hamiltonian. The Hamiltonian parameters g, D, and E were determined. It is concluded that VO2+ and Cr3+ enter into the Li+ places and the charge is compensated by a Li+ vacancy in the VO2+ case and proton vacancies in the Cr3+ case.
Zonar Distribution of 18O in Synthetic Quartz Crystals
Authors: Klemm A. , Röller K. , Hoernes S. 
Published: February 2015

Abstract
The 18O-content in the mantle-zones of a commercial synthetic quartz was found to increase from the seed towards the surface by 7 ‰. Since the growth took place in a closed container, calculations for the evolution towards the steady state of the 18O-transport could be performed. In the steady state the concentrations of 18O and impurities in the growing quartz are uniform.
The Microwave Spectrum of the Bimolecule Trifluoroacetic Acid · · · Cyclopropanecarboxylic Acid
Authors: Antolínez Sonja , Dreizler Helmut , Storm Volker , Sutter Dieter H. , Alonso José L. 
Published: February 2015

Abstract
We have investigated the microwave spectrum of the bimolecule trifluoroacetic acid • • • cyclo-propanecarboxylic acid in the region 1 to 4 GHz, where the low J transitions of this heavy complex appear. The measured μa -R branch transition frequencies were fitted to determine the rotational constants and three centrifugal distortion constants. With the assumption that the structures of the subunits remain unchanged upon complexation, the O • • • O distances of the hydrogen bridge bonds are determined as 2.62 A.