2,405 research outputs found
Zero modes, gauge fixing, monodromies, -functions and all that
We discuss various issues associated with the calculation of the reduced
functional determinant of a special second order differential operator
\boldmath{F}, , with a
generic function , subject to periodic and Dirichlet boundary
conditions. These issues include the gauge-fixed path integral representation
of this determinant, the monodromy method of its calculation and the
combination of the heat kernel and zeta-function technique for the derivation
of its period dependence. Motivations for this particular problem, coming from
applications in quantum cosmology, are also briefly discussed. They include the
problem of microcanonical initial conditions in cosmology driven by a conformal
field theory, cosmological constant and cosmic microwave background problems.Comment: 17 pages, to appear in J. Phys. A: Math. Theor. arXiv admin note:
substantial text overlap with arXiv:1111.447
Geometric phase shift for detection of gravitational radiation
An effect of geometrical phase shift is predicted for a light beam
propagating in the field of a gravitational wave. Gravitational radiation
detection experiments are proposed using this new effect, the corresponding
estimates being given.Comment: LaTeX2e, 12 p
Non-associative geometry and discrete structure of spacetime
A new mathematical theory, non-associative geometry, providing a unified
algebraic description of continuous and discrete spacetime, is introduced.Comment: LATeX2e file, 11 pages, talk given at "Loop's 99 meeting" (Prague,
July 27 - August 1, 1999). To appear in Comment. Math. Univ. Carolin
3,5-Bis(4-chlorobenzylidene)-1-methylpiperidin-4-one
In the title molecule, C20H17Cl2NO, the central heterocyclic ring adopts a flattened boat conformation. The dihedral angles between the planar part of this central heterocyclic ring [maximum deviation = 0.004 (1) Å] and the two almost planar side-chain fragments [maximum deviations = 0.015 (1) and 0.019 (1) Å], that include the aromatic ring and bridging atoms, are 18.1 (1) and 18.0 (1)°. In the crystal, pairs of weak intermolecular C—H⋯O hydrogen bonds link molecules into inversion dimers that form stacks along the a axis. The structure is further stabilized by weak intermolecular C—H⋯π interactions involving the benzene rings
Life after Brexit: United Kingdom Independence Party in post-referendum
The article considers the situation that has developed in British politics after the United
Kingdom European Union membership referendum in 2016. The major causes of the crisis
of the United Kingdom Independence Party are presented. The estimated characteristic and
ways of possible further party development are given
1-Benzyl-3,5-bis(4-chlorobenzylidene)piperidin-4-one
The title compound, C26H21Cl2NO, crystallizes with two symmetry-independent molecules (A and B) in the asymmetric unit. In both molecules, the central heterocyclic ring adopts a sofa conformation. The dihedral angles between the planar part of this central heterocyclic ring [maximum deviations of 0.011 (1) and 0.036 (1) Å in molecules A and B, respectively] and the two almost planar [maximum deviations of 0.020 (1) and 0.008 (1) Å in A and 0.007 (1) and 0.011 (1) in B] side-chain fragments that include the aromatic ring and bridging atoms are 20.1 (1) and 31.2 (1)° in molecule A, and 26.4 (1) and 19.6 (1)° in molecule B. The dihedral angles between the planar part of the heterocyclic ring and the benzyl substituent are 79.7 (1) and 53.2 (1)° in molecules A and B, respectively. In the crystal, weak intermolecular C—H⋯O hydrogen bonds link the two independent molecules into dimers
Quasigroups, Asymptotic Symmetries and Conservation Laws in General Relativity
A new quasigroup approach to conservation laws in general relativity is
applied to study asymptotically flat at future null infinity spacetime. The
infinite-parametric Newman-Unti group of asymptotic symmetries is reduced to
the Poincar\'e quasigroup and the Noether charge associated with any element of
the Poincar\'e quasialgebra is defined. The integral conserved quantities of
energy-momentum and angular momentum are linear on generators of Poincar\'e
quasigroup, free of the supertranslation ambiguity, posess the flux and
identically equal to zero in Minkowski spacetime.Comment: RevTeX4, 5 page
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