819 research outputs found
Description of Double Giant Dipole Resonance within the Phonon Damping Model
In a recent Letter [1] an overall agreement with the experimental data for
the excitation of the single and double giant dipole resonances in relativistic
heavy ion collision in 136Xe and 208Pb nuclei has been reported. We point out
that this agreement is achieved by a wrong calculation of the DGDR excitation
mechanism. We also argue that the agreement with the data for the widths of
resonances is achieved by an unrealistically large value of a model parameter.
[1] Nguyen Dinh Dang, Vuong Kim Au, and Akito Arima, Phys. Rev. Lett. 85
(2000) 1827.Comment: Comment for Phys. Rev. Let
On the AKSZ formulation of the Rozansky-Witten theory and beyond
Using the AKSZ formalism, we construct the Batalin-Vilkovisky master action
for the Rozansky-Witten model, which can be defined for any complex manifold
with a closed (2,0)-form. We also construct the holomorphic version of
Rozansky-Witten theory defined over Calabi-Yau 3-fold.Comment: 12 page
Experimental study of the vidicon system for information recording using the wide-gap spark chamber of gamma - telescope gamma-I
The development of the gamma ray telescope is investigated. The wide gap spark chambers, used to identify the gamma quanta and to determine the directions of their arrival, are examined. Two systems of information recording with the spark chambers photographic and vidicon system are compared
Non-Commutative Batalin-Vilkovisky Algebras, Homotopy Lie Algebras and the Courant Bracket
We consider two different constructions of higher brackets. First, based on a
Grassmann-odd, nilpotent \Delta operator, we define a non-commutative
generalization of the higher Koszul brackets, which are used in a generalized
Batalin-Vilkovisky algebra, and we show that they form a homotopy Lie algebra.
Secondly, we investigate higher, so-called derived brackets built from
symmetrized, nested Lie brackets with a fixed nilpotent Lie algebra element Q.
We find the most general Jacobi-like identity that such a hierarchy satisfies.
The numerical coefficients in front of each term in these generalized Jacobi
identities are related to the Bernoulli numbers. We suggest that the definition
of a homotopy Lie algebra should be enlarged to accommodate this important
case. Finally, we consider the Courant bracket as an example of a derived
bracket. We extend it to the "big bracket" of exterior forms and multi-vectors,
and give closed formulas for the higher Courant brackets.Comment: 42 pages, LaTeX. v2: Added remarks in Section 5. v3: Added further
explanation. v4: Minor adjustments. v5: Section 5 completely rewritten to
include covariant construction. v6: Minor adjustments. v7: Added references
and explanation to Section
Self-adjoint extensions and spectral analysis in Calogero problem
In this paper, we present a mathematically rigorous quantum-mechanical
treatment of a one-dimensional motion of a particle in the Calogero potential
. Although the problem is quite old and well-studied, we believe
that our consideration, based on a uniform approach to constructing a correct
quantum-mechanical description for systems with singular potentials and/or
boundaries, proposed in our previous works, adds some new points to its
solution. To demonstrate that a consideration of the Calogero problem requires
mathematical accuracy, we discuss some "paradoxes" inherent in the "naive"
quantum-mechanical treatment. We study all possible self-adjoint operators
(self-adjoint Hamiltonians) associated with a formal differential expression
for the Calogero Hamiltonian. In addition, we discuss a spontaneous
scale-symmetry breaking associated with self-adjoint extensions. A complete
spectral analysis of all self-adjoint Hamiltonians is presented.Comment: 39 page
The Path Integral Quantization And The Construction Of The S-matrix In The Abelian And Non-Abelian Chern-Simons Theories
The cvariant path integral quantization of the theory of the scalar and
spinor particles interacting through the abelian and non-Abelian Chern-Simons
gauge fields is carried out and is shown to be mathematically ill defined due
to the absence of the transverse components of these gauge fields. This is
remedied by the introduction of the Maxwell or the Maxwell-type (in the
non-Abelian case)term which makes the theory superrenormalizable and guarantees
its gauge-invariant regularization and renormalization. The generating
functionals are constructed and shown to be formally the same as those of QED
(or QCD) in 2+1 dimensions with the substitution of the Chern-Simons propagator
for the photon (gluon) propagator. By constructing the propagator in the
general case, the existence of two limits; pure Chern-Simons and QED (QCD)
after renormalization is demonstrated.
By carrying out carefully the path integral quantization of the non-Abelian
Chern-Simons theories using the De Witt-Fadeev-Popov and the Batalin-Fradkin-
Vilkovisky methods it is demonstrated that there is no need to quantize the
dimensionless charge of the theory. The main reason is that the action in the
exponent of the path integral is BRST-invariant which acquires a zero winding
number and guarantees the BRST renormalizability of the model.
The S-matrix operator is constructed, and starting from this S-matrix
operator novel topological unitarity identities are derived that demand the
vanishing of the gauge-invariant sum of the imaginary parts of the Feynman
diagrams with a given number of intermediate on-shell topological photon lines
in each order of perturbation theory. These identities are illustrated by an
explicit example.Comment: LaTex file, 31 pages, two figure
- …