3,338 research outputs found
Multi-Matrix Models: Integrability Properties and Topological Content
We analyze multi--matrix chain models. They can be considered as
multi--component Toda lattice hierarchies subject to suitable coupling
conditions. The extension of such models to include extra discrete states
requires a weak form of integrability. The discrete states of the --matrix
model are organized in representations of . We solve exactly the
Gaussian--type models, of which we compute several all-genus correlators. Among
the latter models one can classify also the discretized string theory,
which we revisit using Toda lattice hierarchy methods. Finally we analyze the
topological field theory content of the --matrix models: we define primary
fields (which are ), metrics and structure constants and prove that
they satisfy the axioms of topological field theories. We outline a possible
method to extract interesting topological field theories with a finite number
of primaries.Comment: 31 pages, Late
Toda lattice realization of integrable hierarchies
We present a new realization of scalar integrable hierarchies in terms of the
Toda lattice hierarchy. In other words, we show on a large number of examples
that an integrable hierarchy, defined by a pseudodifferential Lax operator, can
be embedded in the Toda lattice hierarchy. Such a realization in terms the Toda
lattice hierarchy seems to be as general as the Drinfeld--Sokolov realization.Comment: 11 pages, Latex (minor changes, to appear in Lett.Math.Phys.
Hamiltonian Structures of the Multi-Boson KP Hierarchies, Abelianization and Lattice Formulation
We present a new form of the multi-boson reduction of KP hierarchy with Lax
operator written in terms of boson fields abelianizing the second Hamiltonian
structure. This extends the classical Miura transformation and the
Kupershmidt-Wilson theorem from the (m)KdV to the KP case. A remarkable
relationship is uncovered between the higher Hamiltonian structures and the
corresponding Miura transformations of KP hierarchy, on one hand, and the
discrete integrable models living on {\em refinements} of the original lattice
connected with the underlying multi-matrix models, on the other hand. For the
second KP Hamiltonian structure, worked out in details, this amounts to finding
a series of representations of the nonlinear \hWinf algebra in terms of
arbitrary finite number of canonical pairs of free fields.Comment: 12 pgs, (changes in abstract, intro and outlook+1 ref added). LaTeX,
BGU-94 / 1 / January- PH, UICHEP-TH/94-
Free field representation of Toda field theories
We study the following problem: can a classical Toda field theory be
represented by means of free bosonic oscillators through a Drinfeld--Sokolov
construction? We answer affirmatively in the case of a cylindrical space--time
and for real hyperbolic solutions of the Toda field equations. We establish in
fact a one--to--one correspondence between such solutions and the space of free
left and right bosonic oscillators with coincident zero modes. We discuss the
same problem for real singular solutions with non hyperbolic monodromy.Comment: 29 pages, Latex, SISSA-ISAS 210/92/E
Generalized q-deformed Correlation Functions as Spectral Functions of Hyperbolic Geometry
We analyse the role of vertex operator algebra and 2d amplitudes from the
point of view of the representation theory of infinite dimensional Lie
algebras, MacMahon and Ruelle functions. A p-dimensional MacMahon function is
the generating function of p-dimensional partitions of integers. These
functions can be represented as amplitudes of a two-dimensional c=1 CFT. In
this paper we show that p-dimensional MacMahon functions can be rewritten in
terms of Ruelle spectral functions, whose spectrum is encoded in the
Patterson-Selberg function of three dimensional hyperbolic geometry.Comment: 12 pages, no figure
Liouville and Toda field theories on Riemann surfaces
We study the Liouville theory on a Riemann surface of genus g by means of
their associated Drinfeld--Sokolov linear systems. We discuss the cohomological
properties of the monodromies of these systems. We identify the space of
solutions of the equations of motion which are single--valued and local and
explicitly represent them in terms of Krichever--Novikov oscillators. Then we
discuss the operator structure of the quantum theory, in particular we
determine the quantum exchange algebras and find the quantum conditions for
univalence and locality. We show that we can extend the above discussion to
Toda theories.Comment: 41 pages, LaTeX, SISSA-ISAS 27/93/E
Genetics of familial non-medullary thyroid carcinoma (FNMTC)
Non-medullary thyroid carcinoma (NMTC) is the most frequent endocrine tumor and originates from the follicular epithelial cells of the thyroid. Familial NMTC (FNMTC) has been defined in pedigrees where two or more first-degree relatives of the patient present the disease in absence of other predisposing environmental factors. Compared to sporadic cases, FNMTCs are often multifocal, recurring more frequently and showing an early age at onset with a worse out-come. FNMTC cases show a high degree of genetic heterogeneity, thus impairing the identification of the underlying molecular causes. Over the last two decades, many efforts in identifying the susceptibility genes in large pedigrees were carried out using linkage-based approaches and genome-wide association studies, leading to the identification of susceptibility loci and variants associated with NMTC risk. The introduction of next-generation sequencing technologies has greatly contrib-uted to the elucidation of FNMTC predisposition, leading to the identification of novel candidate variants, shortening the time and cost of gene tests. In this review we report the most significant genes identified for the FNMTC predisposition. Integrating these new molecular findings in the clinical data of patients is fundamental for an early detection and the development of tailored ther-apies, in order to optimize patient management
BRST analysis of topologically massive gauge theory: novel observations
A dynamical non-Abelian 2-form gauge theory (with B \wedge F term) is endowed
with the "scalar" and "vector" gauge symmetry transformations. In our present
endeavor, we exploit the latter gauge symmetry transformations and perform the
Becchi-Rouet-Stora-Tyutin (BRST) analysis of the four (3 + 1)-dimensional (4D)
topologically massive non-Abelian 2-form gauge theory. We demonstrate the
existence of some novel features that have, hitherto, not been observed in the
context of BRST approach to 4D (non-)Abelian 1-form as well as Abelian 2-form
and 3-form gauge theories. We comment on the differences between the novel
features that emerge in the BRST analysis of the "scalar" and "vector" gauge
symmetries of the theory.Comment: LaTeX file, 14 pages, an appendix added, references expanded, version
to appear in EPJ
Hawking Radiation for Scalar and Dirac Fields in Five Dimensional Dilatonic Black Hole via Anomalies
We study massive scalar fields and Dirac fields propagating in a five
dimensional dilatonic black hole background. We expose that for both fields the
physics can be describe by a two dimensional theory, near the horizon. Then, in
this limit, by applying the covariant anomalies method we find the Hawking flux
by restoring the gauge invariance and the general coordinate covariance, which
coincides with the flux obtained from integrating the Planck distribution for
fermions.Comment: 10 page
Aberration cancellation in quantum interferometry
We report the first experimental demonstration of even-order aberration
cancellation in quantum interferometry. The effect is a spatial counterpart of
the spectral group velocity dispersion cancellation, which is associated with
spectral entanglement. It is manifested in temporal interferometry by virtue of
the multi-parameter spatial-spectral entanglement. Spatially-entangled photons,
generated by spontaneous parametric down conversion, were subjected to spatial
aberrations introduced by a deformable mirror that modulates the wavefront. We
show that only odd-order spatial aberrations affect the quality of quantum
interference
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