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math/9201250
Factor = quotient, uncountable Boolean algebras, number of endomorphism and width
We prove that assuming suitable cardinal arithmetic, if B is a Boolean algebra every homomorphic image of which is isomorphic to a factor, then B has locally small density. We also prove that for an (infinite) Boolean algebra B, the number of subalgebras is not smaller than the number of endomorphisms, and other relate...
1992-01-15
2008-02-03
[ "math.LO", "math.GN" ]
Saharon Shelah
math/9201252
Linear liftings for non complete probability space
We show that it is consistent with ZFC that L^infty (Y,B, nu) has no linear lifting for many non-complete probability spaces (Y,B, nu), in particular for Y=[0,1]^A, B= Borel subsets of Y, nu = usual Radon measure on B .
1992-01-15
2009-10-22
[ "math.LO", "math.FA" ]
Max R. Burke, Saharon Shelah
math/9201253
The universality spectrum of stable unsuperstable theories
It is shown that if T is stable unsuperstable, and aleph_1< lambda =cf(lambda)< 2^{aleph_0}, or 2^{aleph_0} < mu^+< lambda =cf(lambda)< mu^{aleph_0} then T has no universal model in cardinality lambda, and if e.g. aleph_omega < 2^{aleph_0} then T has no universal model in aleph_omega. These results are generalized to k...
1992-01-15
2016-09-06
[ "math.LO" ]
Menachem Kojman, Saharon Shelah
math/9201249
Coding and reshaping when there are no sharps
Assuming 0^sharp does not exist, kappa is an uncountable cardinal and for all cardinals lambda with kappa <= lambda < kappa^{+ omega}, 2^lambda = lambda^+, we present a ``mini-coding'' between kappa and kappa^{+ omega}. This allows us to prove that any subset of kappa^{+ omega} can be coded into a subset, W of kappa^+ ...
1992-01-15
2016-09-06
[ "math.LO" ]
Saharon Shelah, Lee Stanley
math/9201251
Cardinal arithmetic for skeptics
We present a survey of some results of the pcf-theory and their applications to cardinal arithmetic. We review basics notions (in section 1), briefly look at history in section 2 (and some personal history in section 3). We present main results on pcf in section 5 and describe applications to cardinal arithmetic in sec...
1992-01-15
2008-02-03
[ "math.LO" ]
Saharon Shelah
math/9201238
Existence of endo-rigid Boolean algebras
In [Sh:89] we, answering a question of Monk, have explicated the notion of ``a Boolean algebra with no endomorphisms except the ones induced by ultrafilters on it'' (see section 2 here) and proved the existence of one with character density aleph_0, assuming first diamondsuit_{aleph_1} and then only CH. The idea was th...
1992-01-15
2008-02-03
[ "math.LO", "math.GN" ]
Saharon Shelah
math/9211216
A low-technology estimate in convex geometry
Let $K$ be an $n$-dimensional symmetric convex body with $n \ge 4$ and let $K\dual$ be its polar body. We present an elementary proof of the fact that $$(\Vol K)(\Vol K\dual)\ge \frac{b_n^2}{(\log_2 n)^n},$$ where $b_n$ is the volume of the Euclidean ball of radius 1. The inequality is asymptotically weaker than the es...
1992-11-01
2008-02-03
[ "math.MG", "math.FA" ]
Greg Kuperberg (U Chicago)
math/9210218
A characterization of convex hyperbolic polyhedra and of convex polyhedra inscribed in the sphere
We describe a characterization of convex polyhedra in $\h^3$ in terms of their dihedral angles, developed by Rivin. We also describe some geometric and combinatorial consequences of that theory. One of these consequences is a combinatorial characterization of convex polyhedra in $\E^3$ all of whose vertices lie on the ...
1992-10-01
2016-09-06
[ "math.MG" ]
Craig D. Hodgson, Igor Rivin, Warren D. Smith
math/9210222
Keller's cube-tiling conjecture is false in high dimensions
O. H. Keller conjectured in 1930 that in any tiling of $\Bbb R^n$ by unit $n$-cubes there exist two of them having a complete facet in common. O. Perron proved this conjecture for $n\le 6$. We show that for all $n\ge 10$ there exists a tiling of $\Bbb R^n$ by unit $n$-cubes such that no two $n$-cubes have a complete fa...
1992-10-01
2016-09-06
[ "math.MG", "math.CO" ]
Jeffrey C. Lagarias, Peter W. Shor
math/9210213
Piercing convex sets
A family of sets has the $(p,q)$ property if among any $p$ members of the family some $q$ have a nonempty intersection. It is shown that for every $p\ge q\ge d+1$ there is a $c=c(p,q,d)<\infty$ such that for every family $\scr F$ of compact, convex sets in $R^d$ that has the $(p,q)$ property there is a set of at most $...
1992-10-01
2016-09-06
[ "math.MG" ]
Noga Alon, Daniel J. Kleitman
math/9204233
A quasi-polynomial bound for the diameter of graphs of polyhedra
The diameter of the graph of a $d$-dimensional polyhedron with $n$ facets is at most $n^{\log d+2}$
1992-04-01
2008-02-03
[ "math.MG", "math.CO" ]
Gil Kalai, Daniel J. Kleitman
math/9201269
Perspectives on information-based complexity
The authors discuss information-based complexity theory, which is a model of finite-precision computations with real numbers, and its applications to numerical analysis.
1992-01-01
2008-02-03
[ "math.NA" ]
J. F. Traub, Henryk Wo\'zniakowski
math/9201266
Some basic information on information-based complexity theory
Numerical analysts might be expected to pay close attention to a branch of complexity theory called information-based complexity theory (IBCT), which produces an abundance of impressive results about the quest for approximate solutions to mathematical problems. Why then do most numerical analysts turn a cold shoulder t...
1992-01-01
2025-10-20
[ "math.NA", "cs.NA" ]
Beresford N. Parlett
math/9210214
Additive functions on shifted primes
Best possible bounds are obtained for the concentration function of an additive arithmetic function on sequences of shifted primes.
1992-10-01
2008-02-03
[ "math.NT" ]
P. D. T. A. Elliott
math/9207210
Galois theory on the line in nonzero characteristic
The author surveys Galois theory of function fields with non-zero caracteristic and its relation to the structure of finite permutation groups and matrix groups.
1992-07-01
2008-02-03
[ "math.NT", "math.GR" ]
Shreeram S. Abhyankar
math/9204234
Algorithms in algebraic number theory
In this paper we discuss the basic problems of algorithmic algebraic number theory. The emphasis is on aspects that are of interest from a purely mathematical point of view, and practical issues are largely disregarded. We describe what has been done and, more importantly, what remains to be done in the area. We hope t...
1992-04-01
2008-02-03
[ "math.NT" ]
Hendrik W. Lenstra Jr.
math/9204217
On the Selberg class of Dirichlet series: small degrees
In the study of Dirichlet series with arithmetic significance there has appeared (through the study of known examples) certain expectations, namely (i) if a functional equation and Euler product exists, then it is likely that a type of Riemann hypothesis will hold, (ii) that if in addition the function has a simple pol...
1992-04-01
2024-10-10
[ "math.NT" ]
J. Brian Conrey, Amit Ghosh
math/9210227
Voiculescu theorem, Sobolev lemma, and extensions of smooth algebras
We present the analytic foundation of a unified B-D-F extension functor $\operatorname{Ext}_\tau$ on the category of noncommutative smooth algebras, for any Fr\'echet operator ideal $\Cal K_\tau$. Combining the techniques devised by Arveson and Voiculescu, we generalize Voiculescu's theorem to smooth algebras and Fr\'e...
1992-10-01
2016-09-06
[ "math.OA" ]
Xiaolu Wang
math/9204228
The Mackey-Gleason Problem
Let $A$ be a von Neumann algebra with no direct summand of Type $\roman I_2$, and let $\scr P(A)$ be its lattice of projections. Let $X$ be a Banach space. Let $m\:\scr P(A)\to X$ be a bounded function such that $m(p+q)=m(p)+m(q)$ whenever $p$ and $q$ are orthogonal projections. The main theorem states that $m$ has a u...
1992-04-01
2016-09-06
[ "math.OA" ]
L. J. Bunce, J. D. Maitland Wright
math/9212209
A quantum-group-like structure on noncommutative 2-tori
In this paper we show that in the case of noncommutative two-tori one gets in a natural way simple structures which have analogous formal properties as Hopf algebra structures but with a deformed multiplication on the tensor product.
1992-12-01
2016-09-06
[ "math.QA" ]
Andreas Cap, Peter W. Michor, Hermann Schichl
math/9208203
Towards the Chern-Weil homomormism in non-commutative differential geometry
In this short review article we sketch some developments which should ultimately lead to the analogy of the Chern-Weil homomorphism for principal bundles in the realm of non-commutative differential geometry. Principal bundles there should have Hopf algebras as structure `cogroups'. Since the usual machinery of Lie alg...
1992-08-01
2016-09-06
[ "math.QA" ]
Andreas Cap, Peter W. Michor
math/9207209
The Fr\"olicher-Nijenhuis bracket in non-commutative differential geometry
We carry over to a quite general noncommutative setting some of the basic tools of differential geometry, using from the very beginning the setting of convenient vector spaces developed by Froelicher and Kriegl, which allows to carry all of multilinear algebra into this kind of functional analysis with suitably complet...
1992-07-01
2016-09-06
[ "math.QA", "math.FA" ]
Andreas Cap, Andreas Kriegl, Peter W. Michor, Ji\v{r}i Van\v{z}ura
math/9201257
The multigraded Nijenhuis-Richardson Algebra, its universal property and application
We define two $(n+1)$ graded Lie brackets on spaces of multilinear mappings. The first one is able to recognize $n$-graded associative algebras and their modules and gives immediately the correct differential for Hochschild cohomology. The second one recognizes $n$-graded Lie algebra structures and their modules and gi...
1992-01-01
2009-09-25
[ "math.QA" ]
Pierre Lecomte, Peter W. Michor, Hubert Schicketanz
math/9204229
Ramanujan duals and automorphic spectrum
We introduce the notion of the automorphic dual of a matrix algebraic group defined over $Q$. This is the part of the unitary dual that corresponds to arithmetic spectrum. Basic functorial properties of this set are derived and used both to deduce arithmetic vanishing theorems of ``Ramanujan'' type as well as to give a...
1992-04-01
2016-09-06
[ "math.RT", "math.NT" ]
Marc Burger, Jian-Shu Li, Peter Sarnak
math/9204227
Nilpotent orbits, normality, and Hamiltonian group actions
Let $M$ be a $G$-covering of a nilpotent orbit in $\g$ where $G$ is a complex semisimple Lie group and $\g=\text{Lie}(G)$. We prove that under Poisson bracket the space $R[2]$ of homogeneous functions on $M$ of degree 2 is the unique maximal semisimple Lie subalgebra of $R=R(M)$ containing $\g$. The action of $\g'\sime...
1992-04-01
2016-09-06
[ "math.RT" ]
Ranee Brylinski, Bertram Kostant
math/9204222
All unitary representations admit moment mappings
This is a review of [Michor, Peter W.: The moment mapping for a unitary representation, Ann. Global Anal. Geometry, 8, No 3(1990), 299--313] including a careful description of calculus in infinite dimensions. For any unitary representation of an arbitrary Lie group I construct a moment mapping from the space of smooth ...
1992-04-01
2016-09-06
[ "math.RT" ]
Peter W. Michor
math/9201256
The moment mapping for a unitary representation
For any unitary representation of an arbitrary Lie group I construct a moment mapping from the space of smooth vectors of the representation into the dual of the Lie algebra. This moment mapping is equivariant and smooth. For the space of analytic vectors the same construction is possible and leads to a real analytic m...
1992-01-01
2016-09-06
[ "math.RT" ]
Peter W. Michor
math/9204235
Spectral Theory and Representations of Nilpotent Groups
We give an estimate of the number $N(\lambda)$ of eigenvalues $<\lambda$ for the image under an irreducible representation of the ``sublaplacian'' on a stratified nilpotent Lie algebra. We also give an estimate for the trace of the heat-kernel associated with this operator. The estimates are formulated in term of geome...
1992-04-01
2016-09-06
[ "math.SP", "math.RT" ]
Pierre Levy-Bruhl, Abderemane Mohamed, Jean Nourrigat
nucl-th/9212016
Electromagnetic Dissociation of Nuclei in Heavy-Ion Collisions
Large discrepancies have been observed between measured Electromagnetic Dissociation(ED) cross sections and the predictions of the semiclassical Weiz\"acker-Williams-Fermi(WWF) method. In this paper, the validity of the semiclassical approximation is examined. The total cross section for electromagnetic excitation of a...
1992-12-28
2016-09-08
[ "nucl-th" ]
C.J. Benesh and J.L. Friar
nucl-th/9212015
Chaotic Behavior in Warm Deformed Nuclei Induced by Residual Two-Body Interactions
Band mixing calculations in rapidly rotating well-deformed nuclei are presented, investigating the properties of energy levels and rotational transitions as a function of excitation energy. Substantial fragmentation of E2 transitions is found for $E_x \gsim$ 800 keV above yrast, which represents the onset of rotational...
1992-12-25
2009-10-22
[ "nucl-th" ]
M.Matsuo, T.D{\o}ssing, B.Herskind, S.Frauendorf, E.Vigezzi and R.A.Broglia
nucl-th/9212014
Dynamics of antibaryon-baryon annihilation in the Skyrme model
We examine the dynamics of a baryon number zero lump in the Skyrme picture, as a model for annihilation in the $\bar{N}N$ system. We find that radiation propagates at the causal limit as a localized pulse and that the linearized theory gives a good approximation. Both of these results are contrary to findings in the Si...
1992-12-18
2009-10-22
[ "nucl-th" ]
Bin Shao, Niels R. Walet, and R. D. Amado
nucl-th/9212012
High-energy pion-nucleus elastic scattering
We investigate theoretical approaches to pion--nucleus elastic scattering at high energies (300 $\le T_\pi \le$ 1 GeV). A ``model--exact'' calculation of the lowest--order microscopic optical model, carried out in momentum space and including the full Fermi averaging integration, a realistic off--shell pion--nucleon sc...
1992-12-17
2009-10-22
[ "nucl-th" ]
C.M. Chen, D.J. Ernst and M.B. Johnson
nucl-th/9212013
Microscopic approach to pion-nucleus dynamics
Elastic scattering of pions from finite nuclei is investigated utilizing a contemporary, momentum--space first--order optical potential combined with microscopic estimates of second--order corrections. The calculation of the first--order potential includes:\ \ (1)~full Fermi--averaging integration including both the de...
1992-12-17
2009-10-22
[ "nucl-th" ]
C.M. Chen, D.J. Ernst and M.B. Johnson
nucl-th/9212010
Chiral colour-dielectric model with perturbative quantum pions and gluons
Pionic contributions to static nucleon properties are calculated in a chiral extension of the colour-dielectric model. The pion field and residual gluon field are treated perturbatively. It is shown that with a simple choice for the energy of the scalar confining field and in the chiral limit, the system of equations d...
1992-12-17
2016-09-08
[ "nucl-th" ]
L.R. Dodd and D.E. Driscoll
nucl-th/9212011
Colour Transparency in Hadronic Basis
The dynamics of nuclear transparency in hard nuclear reactions is studied by an expansion of the correlator of the hard scattering operator on a hadronic basis. Colour transparency appears as an effect of interference between the amplitudes corresponding to the final state interaction of different intermediate baryonic...
1992-12-17
2007-05-23
[ "nucl-th" ]
A. Bianconi, S. Boffi and D.E. Kharzeev
nucl-th/9212009
Cross Section Fluctuations and Chaoticity in Heavy-Ion Dynamics
Cross section fluctuations in nuclear scattering are briefly reviewed in order to show the main important features. Then chaotic scattering is introduced by means of a very simple model. It is shown that chaoticity produces the same kind of irregular fluctuations observed in light heavy--ion collisions. The transition ...
1992-12-16
2007-05-23
[ "nucl-th" ]
A. Rapisarda
nucl-th/9212008
Kaon-Nucleon Scattering Amplitudes and Z$^*$-Enhancements from Quark Born Diagrams
We derive closed form kaon-nucleon scattering amplitudes using the ``quark Born diagram" formalism, which describes the scattering as a single interaction (here the OGE spin-spin term) followed by quark line rearrangement. The low energy I=0 and I=1 S-wave KN phase shifts are in reasonably good agreement with experimen...
1992-12-15
2009-10-22
[ "nucl-th", "hep-ph" ]
T. Barnes and E.S. Swanson
nucl-th/9212006
Poisson and Porter-Thomas Fluctuations in off-Yrast Rotational Transitions
Fluctuations associated with stretched E2 transitions from high spin levels in nuclei around $^{168}$Yb are investigated by a cranked shell model extended to include residual two-body interactions. It is found that the gamma-ray energies behave like random variables and the energy spectra show the Poisson fluctuation, ...
1992-12-14
2009-10-22
[ "nucl-th" ]
M.Matsuo, T.D{\o}ssing, B.Herskind and S. Frauendorf
nucl-th/9212007
Hyperfine Populations Prior to Muon Capture
It is shown that the 1S level hyperfine populations prior to muon capture will be statistical when either target or beam are unpolarised independent of the atomic level at which the hyperfine interaction becomes appreciable. This assertion holds in the absence of magnetic transitions during the cascade and is true beca...
1992-12-14
2009-10-22
[ "nucl-th" ]
J.G.Congleton
nucl-th/9212005
Microscopic Origin of Quantum Chaos in Rotational Damping
The rotational spectrum of $^{168}$Yb is calculated diagonalizing different effective interactions within the basis of unperturbed rotational bands provided by the cranked shell model. A transition between order and chaos taking place in the energy region between 1 and 2 MeV above the yrast line is observed, associated...
1992-12-14
2009-01-23
[ "nucl-th" ]
M. Matsuo, T. D{\o}ssing, E. Vigezzi, and R.A. Broglia
nucl-th/9212004
The Lamda-N - Sigma-N Interaction with Isobar Coupling and Six-Quark Resonances
The long-range $\Lambda N-\Sigma N$ interaction is modeled by a configuration space meson-exchange potential matrix coupling to channels with $\Delta$ and $\Sigma(1385)$ isobars. An inner boundary condition, based on $R$-matrix theory, replaces form factors for short-range effects and includes the effects of free quark...
1992-12-10
2009-10-22
[ "nucl-th", "hep-ph" ]
W.R. Greenberg and E.L. Lomon
nucl-th/9212003
Relativistic Nuclear Matter with Self-Consistent Correlation Energy
We study relativistic nuclear matter in the $\sigma - \omega$ model including the ring-sum correlation energy. The model parameters are adjusted self-consistently to give the canonical saturation density and binding energy per nucleon with the ring energy included. Two models are considered, mean-field-theory where we ...
1992-12-09
2008-11-26
[ "nucl-th" ]
J. A. McNeil, C. E. Price, and J. R. Shepard
nucl-th/9212002
Exact 1-Fermion Loop Contributions in 1+1 Dimensional Solitons
We find solutions to the 1+1 dimensional scalar-only linear sigma model. A new method is used to compute 1-fermion loop contributions exactly and agreement with published results employing other methods is excellent. A renormalization scheme which differs from that commonly used in such calculations but similar to that...
1992-12-07
2009-10-22
[ "nucl-th" ]
J. R. Shepard, C. E. Price and T. C. Ferr\'ee (University of Colorado Nuclear Physics Lab)
nucl-th/9212001
The Nuclear Response in Delta-Isobar Region in the ($^3\!$He,t) Reaction
The excitation of a $\Delta$-isobar in a finite nucleus in charge--exchange ($^3\!$He,t) reaction is discussed in terms of a nuclear response function. The medium effects modifying a $\Delta$- and a pion propagation were considered for a finite size nucleus. The Glauber approach has been used for distortion of a $^3\!$...
1992-12-02
2009-10-22
[ "nucl-th" ]
V.F.Dmitriev
nucl-th/9211013
Comparison of potential models with the pp scattering data below 350 MeV
We calculate the chi**2 of various NN potential models with respect to the pp scattering data. We find that only the potential models which were explicitly fitted to the pp data give a reasonable description of these data. Most models give a pretty large chi**2 on the very low-energy pp data, due to incorrect 1S0 phase...
1992-11-24
2009-10-22
[ "nucl-th" ]
Vincent Stoks and J.J. de Swart
nucl-th/9211012
Relativistic Mean Field Calculations of $\Lambda $ and $\Sigma $ Hypernuclei
Single--particle spectra of $\Lambda $ and $\Sigma $ hypernuclei are calculated within a relativistic mean--field theory. The hyperon couplings used are compatible with the $\Lambda $ binding in saturated nuclear matter, neutron-star masses and experimental data on $\Lambda $ levels in hypernuclei. Special attention is...
1992-11-23
2008-11-26
[ "nucl-th" ]
N.K. Glendenning, D. Von-Eiff, M. Haft, H. Lenske and M.K. Weigel
nucl-th/9211011
Magnetic Screening in Thermal Yang-Mills Theories
We develop a semiclassical method to calculate the density of magnetic monopoles in non-abelian gauge theories at finite temperature in the dilute gas approximation. This quantity is related to the inverse magnetic screening length for which we obtain $\mu_M = 0.255 g^2T$ in SU(2).
1992-11-23
2008-11-26
[ "nucl-th", "hep-ph" ]
T.S. Biro and B. Mueller
nucl-th/9211010
Physics of the Quark-Gluon Plasma
Central nuclear collisions at energies far above 1 GeV/nucleon may provide for conditions, where the transition from highly excited hadronic matter into quark matter or quark-gluon plasma can be probed. Here I review our current understanding of the physical properties of a quark-gluon plasma and review ideas about the...
1992-11-20
2009-10-22
[ "nucl-th", "hep-ph" ]
Berndt Mueller
nucl-th/9211009
Hot Nuclear Matter : A Variational Approach
We develop a nonperturbative technique in field theory to study properties of infinite nuclear matter at zero temperature as well as at finite temperatures. Here we dress the nuclear matter with off-mass shell pions. The techniques of thermofield dynamics are used for finite temperature calculations. Equation of state ...
1992-11-17
2015-06-26
[ "nucl-th" ]
H. Mishra, S.P. Misra, P.K. Panda, B.K. Parida
nucl-th/9211008
Test of Scalar Meson Structure in $\phi$ Radiative Decays
We show that $\phi$ radiative decays into scalar mesons [$f_0$(975), $a_0$(980)$\equiv S$] can provide important clues on the internal structures of these mesons. Radiative decay widths vary widely: $B.R.=10^{-4}-10^{-6}$ depending on the substructures ($q\bar q$, $qq\bar q\bar q$, $K\bar K$, glueball). Hence, we could...
1992-11-12
2007-05-23
[ "nucl-th", "hep-ph" ]
S. Kumano (U. Mainz (present address) and INS-U. of Tokyo)
nucl-th/9211007
On the pion-nucleon coupling constant
In view of persisting misunderstanding about the determination of the pion-nucleon coupling constants in the Nijmegen multienergy partial-wave analyses of pp, np, and pbar-p scattering data, we present additional information which may clarify several points of discussion. We comment on several recent papers addressing ...
1992-11-11
2008-11-26
[ "nucl-th" ]
Vincent Stoks, Rob Timmermans, and J.J. de Swart
nucl-th/9211006
$q^2$-Dependence of Meson Mixing in Few-Body Charge Symmetry Breaking: $\pi^o-\eta$ Mixing to One Loop in Chiral Perturbation Theory
It is pointed out that the meson mixing matrix elements usually considered responsible for the bulk of the observed few-body charge symmetry breaking are naturally $q^2$-dependent in QCD. For $\pi^o-\eta$ mixing, using the usual representation of the pseudoscalar fields, the leading $q^2$ dependence can be explicitly c...
1992-11-10
2009-10-22
[ "nucl-th" ]
Kim Maltman
nucl-th/9211004
Atomic Parity Nonconservation: Electroweak Parameters and Nuclear Structure
There have been suggestions to measure atomic parity nonconservation (PNC) along an isotopic chain, by taking ratios of observables in order to cancel complicated atomic structure effects. Precise atomic PNC measurements could make a significant contribution to tests of the Standard Model at the level of one loop radia...
1992-11-05
2008-11-26
[ "nucl-th" ]
S.J. Pollock, E. N. Fortson and L. Wilets
nucl-th/9211005
Self-consistent anisotropic oscillator with cranked angular and vortex velocities
The Kelvin circulation is the kinematical Hermitian observable that measures the true character of nuclear rotation. For the anisotropic oscillator, mean field solutions with fixed angular momentum and Kelvin circulation are derived in analytic form. The cranking Lagrange multipliers corresponding to the two constraint...
1992-11-05
2008-11-26
[ "nucl-th" ]
G. Rosensteel
nucl-th/9211003
Meson Mass Spectrum from Relativistic Equations in Configuration Space
A method is described for solving relativistic quasi-potential equations in configuration space. The Blankenbecler-Sugar-Logunov-Tavkhelidze and an equal-time equation, both relativistic covariant two-body equations containing the full Dirac structure of positive and negative energy states, are studied in detail. These...
1992-11-04
2007-05-23
[ "nucl-th", "hep-ph" ]
P.C. Tiemeijer and J.A. Tjon
nucl-th/9211002
Sum Rule Description of Color Transparency
The assumption that a small point-like configuration does not interact with nucleons leads to a new set of sum rules that are interpreted as models of the baryon-nucleon interaction. These models are rendered semi-realistic by requiring consistency with data for cross section fluctuations in proton-proton diffractive c...
1992-11-03
2008-11-26
[ "nucl-th" ]
L. Frankfurt, W. R. Greenberg, G. A. Miller, M. Strikman
nucl-th/9211001
Pionic effects in deep inelastic scattering off nuclei
The structure functions calculated in the Chiral bag model reproduce quite well, after appropriate perturbative evolution to large energy scales, the experimental data. We use these results to interpret the structure of the $EMC$ data as a quenching of the pion decay constant due to the in medium behavior of the nucleo...
1992-11-02
2015-06-26
[ "nucl-th", "hep-ph" ]
P. Gonzalez and V. Vento
nucl-th/9210020
Coalescence, Percolation and Nuclear Multifragmentation
We show that the coalescence model for fragment formation leads to an approximate site percolation model. Features characteristic of a percolation model also appear in microscopic models of disassembly.
1992-10-30
2009-10-22
[ "nucl-th" ]
S. Das Gupta, C. Gale and K. Haglin
nucl-th/9210019
Finite volume of baryons and the mass limit for neutron stars
We confirmed the following idea by numerical calculation: The extended structure of baryons may make the nuclear equation of state stiffer at higher density while keeping the compression modulus for normal nuclear matter around its empirical value $K=240MeV$.The model built in this wayy fits all empirical data for norm...
1992-10-26
2009-10-22
[ "nucl-th", "astro-ph" ]
Qi-Ren Zhang, Bo-Qiang Ma and Walter Greiner
nucl-th/9210018
Electromagnetic Decays of Hyperons (II)
Excited negative parity hyperon masses are calculated in a chiral bag model in which the pion and the kaon fields are treated as perturbations. We also calculate the hadronic widths of $\lama$ and $\lamb$ as well as the coupling constants of the lightest $I=0$ excited hyperon to the meson-baryon channels, and discuss h...
1992-10-23
2009-10-22
[ "nucl-th" ]
Y. Umino and F. Myhrer
nucl-th/9210017
Quartets of superdeformed bands and supersymmetry breaking
We examine the prediction of supersymmetric quantum mechanics that bands with identical gamma-ray energies occur in quartets. The experimental data suggest that this scenario is actually realized in nature. In the $A=150$ mass region, four known pairs of isospectral bands can be grouped in two quartets, while there are...
1992-10-22
2015-06-26
[ "nucl-th" ]
R.D. Amado, R. Bijker, F. Cannata, J.P. Dedonder and N.R. Walet
nucl-th/9210016
Transverse response functions in the $\Delta$-resonance region
We calculate transverse response functions for quasi-elastic electron scattering at high momentum transfers in a relativistic Hartree approximation in configuration space. We treat the excitation of the $\Delta$ resonance using its free mass and width. Good agreement with experiment is found in the dip region.
1992-10-22
2008-11-26
[ "nucl-th" ]
E. Rost, C. E. Price and J. R. Shepard (Department of Physics, University of Colorado, Boulder)
nucl-th/9210015
Skyrmions and the Nuclear Force
The derivation of the nucleon-nucleon force from the Skyrme model is reexamined. Starting from previous results for the potential energy of quasistatic solutions, we show that a calculation using the Born-Oppenheimer approximation properly taking into account the mixing of nucleon resonances, leads to substantial centr...
1992-10-20
2008-11-26
[ "nucl-th" ]
Niels R. Walet and R. D. Amado
nucl-th/9210013
Effects of Octupole Vibrations on Quasiparticle Modes of Excitation in Superdeformed $^{193}$Hg
A particle-vibration coupling calculation based on the RPA and the cranked shell model has been carried out for superdeformed rotational bands in $^{193}$Hg. The result suggests that properties of single-particle motions in superdeformed nuclei may be significantly affected by coupling effects with low-frequency octupo...
1992-10-20
2017-02-01
[ "nucl-th" ]
Takashi Nakatsukasa, Shoujirou Mizutori, Kenichi Matsuyanagi
nucl-th/9210014
Monte Carlo methods for the nuclear shell model
We present novel Monte Carlo methods for treating the interacting shell model that allow exact calculations much larger than those heretofore possible. The two-body interaction is linearized by an auxiliary field; Monte Carlo evaluation of the resulting functional integral gives ground-state or thermal expectation valu...
1992-10-20
2008-11-26
[ "nucl-th" ]
C. W. Johnson, S. E. Koonin, G. H. Lang, and W. E. Ormand
nucl-th/9210012
Riemann's theorem for quantum tilted rotors
The angular momentum, angular velocity, Kelvin circulation, and vortex velocity vectors of a quantum Riemann rotor are proven to be either (1) aligned with a principal axis or (2) lie in a principal plane of the inertia ellipsoid. In the second case, the ratios of the components of the Kelvin circulation to the corresp...
1992-10-19
2008-11-26
[ "nucl-th" ]
G. Rosensteel and A.L. Goodman
nucl-th/9210011
Relativistic Corrections to the Triton Binding Energy
The influence of relativity on the triton binding energy is investigated. The relativistic three-dimensional version of the Bethe-Salpeter equation proposed by Blankenbecler and Sugar (BbS) is used. Relativistic (non-separable) one-boson-exchange potentials (constructed in the BbS framework) are employed for the two-nu...
1992-10-13
2008-11-26
[ "nucl-th" ]
F. Sammarruca, D. P. Xu, and R. Machleidt
nucl-th/9210007
Old Problems in Low-Energy $K N$ Physics and Perspectives Opening Up at New Machines
We survey the open problems in low--energy $KN$ physics, in the perspective of using the new machines presently planned, such as the $\phi$--factory DA$\Phi$NE at I.N.F.N. Nat. Labs. in Frascati (as a source of {\sl tagged}, low--energy kaons) and the KAON Factory at TRIUMF (as a producer of intense, intermediate--ener...
1992-10-12
2016-08-14
[ "nucl-th", "hep-ph" ]
Paolo M. Gensini (Dip. di Fisica dell{\'} Universit\`a di Perugia, and I.N.F.N., Sezione di Perugia, Italy) and Galileo Violini (Centro Internacional de F\'isica, Santa Fe de Bogot\'a, Colombia, Dip. di Fisica dell{\'} Universit\`a della Calabria, Rende (Cosenza), Italy, and I.N.F.N., Gruppo Collegato di Cosenz...
nucl-th/9210006
Anatomy of the Soft-Photon Approximation in Hadron-Hadron Bremsstrahlung
A modified Low procedure for constructing soft-photon amplitudes has been used to derive two general soft-photon amplitudes, a two-s-two-t special amplitude $M^{TsTts}_{\mu}$ and a two-u-two-t special amplitude $M^{TuTts}_{\mu}$, where s, t and u are the Mandelstam variables. $M^{TsTts}_{\mu}$ depends only on the elast...
1992-10-12
2009-10-22
[ "nucl-th" ]
M. K. Liou, Dahang Lin, and B. F. Gibson
nucl-th/9210008
Low-Energy $KN$ Interactions at a $\phi$-Factory
The paper is the written version of a talk presented at the "VIIth Winter School of Hadronic Physics", held in Folgaria (Trento), Italy, February 10--15, 1992. We intend to illustrate in this lecture the possibilities opening up at machines planned for the nineties for low--energy kaon--nucleon interactions, keeping ...
1992-10-12
2007-05-23
[ "nucl-th", "hep-ph" ]
Paolo M. Gensini (Dip. di Fisica dell{\'} Universit\`a di Perugia, Perugia, and I.N.F.N., Sezione di Perugia, Italy)
nucl-th/9210009
Low-Energy Kaon Interactions and Scattering on Nucleons and Light Nuclei
A chapter to be included in "The DA$\mit\Phi$NE Physics Handbook" by the DA$\Phi$NE Theory Working Group, this paper covers the phenomenology of low--energy $K N$ physics, with particular emphasis on the problems still to be solved by a careful experimental investigation and on the theoretical tools to analyse it.
1992-10-12
2007-05-23
[ "nucl-th", "hep-ph" ]
Paolo M. Gensini (Dip. di Fisica dell{\'} Universit\`a di Perugia, Perugia, and I.N.F.N., Sezione di Perugia, Italy)
nucl-th/9210010
Saturation in the Nuclear Matter Problem
Once density-dependent meson masses are introduced into the nuclear many-body problem, conventional mechanisms for saturation no longer operate. We suggest that a loop correction, essentially the introduction of the axial vector coupling $g_A(\rho,k)$ as function of density $\rho$ and momentum $k$, can bring about satu...
1992-10-12
2007-05-23
[ "nucl-th" ]
G. E. Brown and R. Machleidt
nucl-th/9210005
Resonances in $\Lambda d$ Scattering and the $\Sigma$-hypertriton
Using separable $NN$ and $\Lambda N$-$\Sigma N$ potentials in the Faddeev equations, we have demonstrated that the predicted enhancement in the $\Lambda d$ cross section near the $\Sigma d$ threshold is associated with resonance poles in the scattering amplitude. The positions of these poles, on the second Riemann shee...
1992-10-08
2009-10-22
[ "nucl-th" ]
I. R. Afnan and B. F. Gibson
nucl-th/9210004
Quadrupole Contribution to Two Neutron Removal in Heavy Ion Collisions
In this report, electric quadrupole corrections to the two neutron removal cross section measured in heavy ion collisions are estimated for $^{197}$Au and $^{59}$Co targets. The quadrupole process is assumed to proceed primarily through excitation of the giant isovector quadrupole resonance, which then decays by neutro...
1992-10-04
2008-11-26
[ "nucl-th" ]
C.J. Benesh
nucl-th/9210003
Modelling the Off-Shell Dependence of $\pi^{o}- \eta$ Mixing with Quark Loops
It is shown that including form factors for the quark-pseudoscalar meson couplings of the Georgi-Manohar chiral quark model allows one to obtain the leading off-shell dependence of $\pi^{o}- \eta$ mixing (as predicted by chiral perturbation theory) from the effect of quark loops on the meson propagators. Implications f...
1992-10-02
2008-11-26
[ "nucl-th", "hep-ph" ]
Kim Maltman and T. Goldman
nucl-th/9210002
Quark Delocalization, Color Screening, and Nuclear Intermediate Range Attraction
We consider the effect of including quark delocalization and color screening, in the nonrelativistic quark cluster model, on baryon-baryon potentials and phase shifts. We find that the inclusion of these additional effects allows a good qualitative description of both.
1992-10-01
2008-11-26
[ "nucl-th" ]
Fan Wang, Guang-han Wu, Li-jian Teng, and T. Goldman
nucl-th/9210001
An Interactive NeXTstep Interface to a Fortran Code for Solving Coupled Differential Equations
This paper describes a user-friendly frontend to a Fortran program that integrates coupled nonlinear ordinary differential equations. The user interface is built using the NeXTstep Interface Builder, together with a public-domain graphical palette for displaying intermediate and final results. In running the code for a...
1992-10-01
2009-10-22
[ "nucl-th" ]
Richard R. Silbar (LANL)
adap-org/9312001
Soft Turbulence in the Atmospheric Boundary Layer
In this work we compare the spectral properties of the daily medium temperature fluctuations with the experimental results of the Chicago Group, in which the local temperature fluctuations were measured in a helium cell. The results suggest that the dynamics of the daily temperature fluctuations is determined by the of...
1993-12-08
2019-08-15
[ "adap-org", "nlin.AO" ]
Imre M. J\'anosi (Department of Atomic Physics, E\"otv\"os University Budapest) and G\'abor Vattay (Department of Solid State Physics, E\"otv\"os University Budapest)
adap-org/9311005
Parametric ordering of complex systems
Cellular automata (CA) dynamics are ordered in terms of two global parameters, computable {\sl a priori} from the description of rules. While one of them (activity) has been used before, the second one is new; it estimates the average sensitivity of rules to small configurational changes. For two well-known families of...
1993-12-01
2009-10-22
[ "adap-org", "chao-dyn", "nlin.AO", "nlin.CD" ]
P.-M. Binder (IIASA, Laxenburg, Austria and Wolfson College, Oxford, UK)
adap-org/9311004
Scaling behaviour in daily air humidity fluctuations
We show that the daily average air humidity fluctuations exhibit non-trivial $1/f^{\alpha}$ behaviour which different from the spectral properties of other meteorological quantities. This feature and the fractal spatial strucure found in clouds make it plausible to regard air humidity fluctuations as a manifestation of...
1993-11-29
2009-10-22
[ "adap-org", "cond-mat", "nlin.AO" ]
Gabor Vattay (Niels Bohr Institute, Copenhagen, Denmark) Andrea Harnos (University of Veterinary Science, Department of Biomathematics and Computer Science, Budapest, Hungary)
adap-org/9311003
Chaos as a Source of Complexity and Diversity in Evolution
The relevance of chaos to evolution is discussed in the context of the origin and maintenance of diversity and complexity. Evolution to the edge of chaos is demonstrated in an imitation game. As an origin of diversity, dynamic clustering of identical chaotic elements, globally coupled each to other, is briefly reviewed...
1993-11-25
2008-02-03
[ "adap-org", "nlin.AO", "q-bio" ]
Kunihiko Kaneko (University of Tokyo, Komaba)
adap-org/9311001
Cell Division, Differentiation and Dynamic Clustering
A novel mechanism for cell differentiation is proposed, based on the dynamic clustering in a globally coupled chaotic system. A simple model with metabolic reaction, active transport of chemicals from media, and cell division is found to show three successive stages with the growth of the number of cells; coherent grow...
1993-11-25
2009-10-22
[ "adap-org", "nlin.AO", "q-bio" ]
Kunihiko Kaneko(University of Tokyo, Komaba), Tetsuya Yomo( Osaka University)
adap-org/9311002
Imitation Games
Mutual imitation games among artificial birds are studied. By employing a variety of mappings and game rules, the evolution to the edge between chaos and windows is universally confirmed. Some other general features are observed, including punctuated equilibria, and successive alternations of dominant species with temp...
1993-11-25
2008-02-03
[ "adap-org", "nlin.AO", "q-bio" ]
Kunihiko Kaneko (University of Tokyo,Komaba) Junji Suzuki (University of Tokyo,Komaba)
adap-org/9309001
On the Threshold of Chaos in Random Boolean Cellular Automata
A random boolean cellular automaton is a network of boolean gates where the inputs, the boolean function, and the initial state of each gate are chosen randomly. In this article, each gate has two inputs. Let $a$ (respectively $c$) be the probability the the gate is assigned a constant function (respectively a non-cana...
1993-09-16
2008-02-03
[ "adap-org", "nlin.AO" ]
James F. Lynch (Clarkson University)
adap-org/9307001
Dynamics of Earthquake Faults
We present an overview of our ongoing studies of the rich dynamical behavior of the uniform, deterministic Burridge--Knopoff model of an earthquake fault. We discuss the behavior of the model in the context of current questions in seismology. Some of the topics considered include: (1) basic properties of the model, suc...
1993-08-05
2009-10-22
[ "adap-org", "chao-dyn", "nlin.AO", "nlin.CD", "nlin.PS", "patt-sol" ]
J.M. Carlson (Dept. of Physics, UC Santa Barbara), J.S. Langer (Institute for Theoretical Physics, UC Santa Barbara), and B.E. Shaw (Lamont-Doherty Earth Observatory, Columbia University)
adap-org/9306005
Prediction and Adaptation in an Evolving Chaotic Environment
We describe the results of analytic calculations and computer simulations of adaptive predictors (predictive agents) responding to an evolving chaotic environment and to one another. Our simulations are designed to quantify adaptation and to explore co-adaptation for a simple calculable model of a complex adaptive syst...
1993-06-28
2008-02-03
[ "adap-org", "chao-dyn", "nlin.AO", "nlin.CD" ]
Alfred H\"ubler and David Pines (Santa Fe Institute and Physics Department, University of Illinois)
adap-org/9306004
Exact solutions for a mean-field Abelian sandpile
We introduce a model for a sandpile, with N sites, critical height N and each site connected to every other site. It is thus a mean-field model in the spin-glass sense. We find an exact solution for the steady state probability distribution of avalanche sizes, and discuss its asymptotics for large N.
1993-06-14
2009-10-22
[ "adap-org", "cond-mat", "nlin.AO" ]
Steven A. Janowsky (Rutgers) and Claude A. Laberge (Rutgers)
adap-org/9306002
Swarms, Phase Transitions, and Collective Intelligence
A spacially extended model of the collective behavior of a large number of locally acting organisms is proposed in which organisms move probabilistically between local cells in space, but with weights dependent on local morphogenetic substances, or morphogens. The morphogens are in turn are effected by the passage of a...
1993-06-11
2008-06-25
[ "adap-org", "nlin.AO", "q-bio.PE" ]
Mark M. Millonas (Center for Nonlinear Studies and Theoretical Division, LANL and Santa Fe Institute)
adap-org/9306003
Dynamics, Computation, and the "Edge of Chaos": A Re-Examination
In this paper we review previous work and present new work concerning the relationship between dynamical systems theory and computation. In particular, we review work by Langton \cite{Langton90} and Packard \cite{Packard88} on the relationship between dynamical behavior and computational capability in cellular automata...
1993-06-11
2008-02-03
[ "adap-org", "nlin.AO" ]
M. Mitchell (SFI), J. P. Crutchfield (UC Berkeley), P. T. Hraber (SFI)
adap-org/9306001
A nonequilibrium statistical field theory of swarms and other spatially extended complex systems
A class of models with applications to swarm behavior as well as many other types of spatially extended complex biological and physical systems is studied. Internal fluctuations can play an active role in the organization of the phase structure of such systems. Consequently, it is not possible to fully understand the b...
1993-06-10
2008-02-03
[ "adap-org", "nlin.AO" ]
Mark M. Millonas (CNLS and Theoretical Division, LANL; and Santa Fe Institute)
adap-org/9305002
Biased Random-Walk Learning: A Neurobiological Correlate to Trial-and-Error
Neural network models offer a theoretical testbed for the study of learning at the cellular level. The only experimentally verified learning rule, Hebb's rule, is extremely limited in its ability to train networks to perform complex tasks. An identified cellular mechanism responsible for Hebbian-type long-term potentia...
1993-06-02
2008-02-03
[ "adap-org", "nlin.AO", "q-bio" ]
Russell W. Anderson (Los Alamos National Laboratory)
adap-org/9305001
A Criterion for Stability in Random Boolean Cellular Automata
Random boolean cellular automata are investigated, where each gate has two randomly chosen inputs and is randomly assigned a boolean function of its inputs. The effect of non-uniform distributions on the choice of the boolean functions is considered. The main results are that if the gates are more likely to be assigned...
1993-05-11
2008-02-03
[ "adap-org", "nlin.AO" ]
James F. Lynch (Clarkson University)
adap-org/9304001
Antichaos in a Class of Random Boolean Cellular Automata
A variant of Kauffman's model of cellular metabolism is presented. It is a randomly generated network of boolean gates, identical to Kauffman's except for a small bias in favor of boolean gates that depend on at most one input. The bias is asymptotic to 0 as the number of gates increases. Upper bounds on the time until...
1993-04-26
2009-10-22
[ "adap-org", "nlin.AO" ]
James F. Lynch (Department of Mathematics and Computer Science, Clarkson University)
adap-org/9303003
Revisiting the Edge of Chaos: Evolving Cellular Automata to Perform Computations
We present results from an experiment similar to one performed by Packard (1988), in which a genetic algorithm is used to evolve cellular automata (CA) to perform a particular computational task. Packard examined the frequency of evolved CA rules as a function of Langton's lambda parameter (Langton, 1990), and interpre...
1993-03-31
2008-02-03
[ "adap-org", "nlin.AO" ]
Melanie Mitchell and Peter Hraber (Santa Fe Institute) and James P. Crutchfield (University of California, Berkeley)
adap-org/9303002
Evolution to the Edge of Chaos in Imitation Game
Motivated by the evolution of complex bird songs, an abstract imitation game is proposed to study the increase of dynamical complexity: Artificial "birds" display a "song" time series to each other, and those that imitate the other's song better win the game. With the introduction of population dynamics according to th...
1993-03-08
2008-06-25
[ "adap-org", "nlin.AO", "q-bio.PE" ]
Kunihiko Kaneko and Junji Suzuki
adap-org/9303001
The length of a typical Huffman codeword
If p is the probability of a letter of a memoryless source, the length l of the corresponding binary Huffman codeword can be very different from the value -log p. We show that, nevertheless, for a typical letter, l is approximately equal to -log p. More precisely, the probability that l differs from -log p by more than...
1993-03-05
2008-02-03
[ "adap-org", "nlin.AO" ]
R. Schack (University of New Mexico)
alg-geom/9312012
Enumeration of $n$-fold tangent hyperplanes to a surface
For each $1\leq n\leq6$ we present formulas for the number of $n-$nodal curves in an $n-$dimensional linear system on a smooth, projective surface. This yields in particular the numbers of rational curves in the system of hyperplane sections of a generic $K3-$surface imbedded in \p{n} by a complete system of curves of ...
1993-12-21
2008-02-03
[ "alg-geom", "math.AG" ]
Israel Vainsencher
alg-geom/9312011
Components of the Stack of Torsion-Free Sheaves of Rank 2 on Ruled Surfaces
Let S be a ruled surface without sections of negative self-intersection. We classify the irreducible components of the moduli stack of torsion-free sheaves of rank 2 sheaves on S. We also classify the irreducible components of the Brill-Noether loci in Hilb^N(P1xP1) given by W_N^0(D)={[X] | h^1(I_X(D)) >= 1 } for D an ...
1993-12-20
2008-02-03
[ "alg-geom", "math.AG" ]
Charles H. Walter
alg-geom/9312010
On the Harder-Narasimhan Filtration for Coherent Sheaves on P2: I
Let E be a torsion-free sheaf on P2. We give an effective method which uses the Hilbert function of E to construct a weak version of the Harder-Narasimhan filtration of a torsion-free sheaf on P2 subject only to the condition that E be sufficiently general among sheaves with that Hilbert function. This algorithm uses o...
1993-12-20
2008-02-03
[ "alg-geom", "math.AG" ]
Charles H. Walter
alg-geom/9312009
Rational curves on Calabi-Yau threefolds
This note is a survey of the enumerative geometry of rational curves on Calabi-Yau threefolds, based on a talk given by the author at the May 1991 Workshop on Mirror Symmetry at MSRI. An earlier version appeared in "Essays on Mirror Manifolds"; this version corrects typographical errors that appeared in print, gives a ...
1993-12-16
2008-02-03
[ "alg-geom", "hep-th", "math.AG" ]
Sheldon Katz