553 research outputs found
The Complexity of Vector Spin Glasses
We study the annealed complexity of the m-vector spin glasses in the
Sherrington-Kirkpatrick limit. The eigenvalue spectrum of the Hessian matrix of
the Thouless-Anderson-Palmer (TAP) free energy is found to consist of a
continuous band of positive eigenvalues in addition to an isolated eigenvalue
and (m-1) null eigenvalues due to rotational invariance. Rather surprisingly,
the band does not extend to zero at any finite temperature. The isolated
eigenvalue becomes zero in the thermodynamic limit, as in the Ising case (m=1),
indicating that the same supersymmetry breaking recently found in Ising spin
glasses occurs in vector spin glasses.Comment: 4 pages, 2 figure
Algebraic renormalization of the BF Yang-Mills Theory
We discuss the quantum equivalence, to all orders of perturbation theory,
between the Yang-Mills theory and its first order formulation through a second
rank antisymmetric tensor field. Moreover, the introduction of an additional
nonphysical vector field allows us to interpret the Yang-Mills theory as a kind
of perturbation of the topological BF model.Comment: 14 pages, some references and acknowledgments added, version to
appear in Phys.Lett.
A Renormalized Supersymmetry in the Topological Yang-Mills Field Theory
We reconsider the algebraic BRS renormalization of Witten's topological
Yang-Mills field theory by making use of a vector supersymmetry Ward identity
which improves the finiteness properties of the model. The vector
supersymmetric structure is a common feature of several topological theories.
The most general local counterterm is determined and is shown to be a trivial
BRS-coboundary.Comment: 18 pages, report REF. TUW 94-10 and UGVA-DPT 1994/07-85
Non-Uniqueness of Quantized Yang-Mills Theories
We consider quantized Yang-Mills theories in the framework of causal
perturbation theory which goes back to Epstein and Glaser. In this approach
gauge invariance is expressed by a simple commutator relation for the S-matrix.
The most general coupling which is gauge invariant in first order contains a
two-parametric ambiguity in the ghost sector - a divergence- and a
coboundary-coupling may be added. We prove (not completely) that the higher
orders with these two additional couplings are gauge invariant, too. Moreover
we show that the ambiguities of the n-point distributions restricted to the
physical subspace are only a sum of divergences (in the sense of vector
analysis). It turns out that the theory without divergence- and
coboundary-coupling is the most simple one in a quite technical sense. The
proofs for the n-point distributions containing coboundary-couplings are given
up to third or fourth order only, whereas the statements about the
divergence-coupling are proven in all orders.Comment: 22 pages. The paper is written in TEX. The necessary macros are
include
Numerical study of the scaling properties of SU(2) lattice gauge theory in Palumbo non-compact regularization
In the framework of a non-compact lattice regularization of nonabelian gauge
theories we look, in the SU(2) case, for the scaling window through the
analysis of the ratio of two masses of hadronic states. In the two-dimensional
parameter space of the theory we find the region where the ratio is constant,
and equal to the one in the Wilson regularization. In the scaling region we
calculate the lattice spacing, finding it at least 20% larger than in the
Wilson case; therefore the simulated physical volume is larger.Comment: 24 pages, 7 figure
The Complexity of Ising Spin Glasses
We compute the complexity (logarithm of the number of TAP states) associated
with minima and index-one saddle points of the TAP free energy. Higher-index
saddles have smaller complexities. The two leading complexities are equal,
consistent with the Morse theorem on the total number of turning points, and
have the value given in [A. J. Bray and M. A. Moore, J. Phys. C 13, L469
(1980)]. In the thermodynamic limit, TAP states of all free energies become
marginally stable.Comment: Typos correcte
String Theory and the Fuzzy Torus
We outline a brief description of non commutative geometry and present some
applications in string theory. We use the fuzzy torus as our guiding example.Comment: Invited review for IJMPA rev1: an imprecision corrected and a
reference adde
From Koszul duality to Poincar\'e duality
We discuss the notion of Poincar\'e duality for graded algebras and its
connections with the Koszul duality for quadratic Koszul algebras. The
relevance of the Poincar\'e duality is pointed out for the existence of twisted
potentials associated to Koszul algebras as well as for the extraction of a
good generalization of Lie algebras among the quadratic-linear algebras.Comment: Dedicated to Raymond Stora. 27 page
RNA Pore Translocation with Static and Periodic Forces: Effect of Secondary and Tertiary Elements on Process Activation and Duration
We use MD simulations to study the pore translocation properties of a pseudoknotted viral RNA. We consider the 71-nucleotide-long xrRNA from the Zika virus and establish how it responds when driven through a narrow pore by static or periodic forces applied to either of the two termini. Unlike the case of fluctuating homopolymers, the onset of translocation is significantly delayed with respect to the application of static driving forces. Because of the peculiar xrRNA architecture, activation times can differ by orders of magnitude at the two ends. Instead, translocation duration is much smaller than activation times and occurs on time scales comparable at the two ends. Periodic forces amplify significantly the differences at the two ends, for both activation times and translocation duration. Finally, we use a waiting-times analysis to examine the systematic slowing downs in xrRNA translocations and associate them to the hindrance of specific secondary and tertiary elements of xrRNA. The findings provide a useful reference to interpret and design future theoretical and experimental studies of RNA translocation
Explicit construction of the classical BRST charge for nonlinear algebras
We give an explicit formula for the Becchi-Rouet-Stora-Tyutin (BRST) charge
associated with Poisson superalgebras. To this end, we split the master
equation for the BRST charge into a pair of equations such that one of them is
equivalent to the original one. We find the general solution to this equation.
The solution possesses a graphical representation in terms of diagrams.Comment: 9 pages; v2,v3 minor corrections, references added for v
- …