On higher order gravities, their analogy to GR, and dimensional dependent version of Duff’s trace anomaly relation

An almost brief, though lengthy, review introduction about the long history of higher order gravities and their applications, as employed in the literature, is provided. We review the analogous procedure between higher order gravities and GR, as described in our previous works, in order to highlight/manipulate its important achievements. Amongst which are presentation of an easy classification of higher order Lagrangians and its employment as a criteria in order to distinguish correct metric theories of gravity. For example, it does not permit the inclusion of only one of the second order Lagrangians in isolation. But, it does allow the inclusion of the cosmological term. We also discuss on the compatibility of our procedure and the Mach idea. We derive a dimensional dependent version of Duff’s trace anomaly relation, which in four-dimension is the same as the usual Duff relation. The Lanczos Lagrangian satisfies this new constraint in any dimension. The square of the Weyl tensor identically satisfies it independent of dimension, however, this Lagrangian satisfies the previous relation only in three and four dimensions.     

Improved but low-x approximated relation betweenF 2 p scaling violation and gluon momentum distribution function

We present a brief analysis on the approximate methods for the determination of gluon distribution from the scaling violation of proton structureF ₂ ^p in the low-x limit. In the leading order, a general low-x approximated relation is presented having more accuracy than the previous methods. Next-to-leading order correction is presented incorporating double-log-approximation. The proposed method is found to give good agreement with data. It may also be used to discriminate between the sets of gluon distributions in the low-x.     

Algebraic Quantization of Causal Sets

A scheme for an algebraic quantization of the causal sets of Sorkin et al. ispresented. The suggested scenario is along the lines of a similar algebraizationand quantum interpretation of finitary topological spaces due to Zapatrin and thisauthor. To be able to apply the latter procedure to causal sets Sorkin's 'semanticswitch' from 'partially ordered sets as finitary topological spaces' to 'partiallyordered sets as locally finite causal sets' is employed. The result is the definition of'quantum causal sets'. Such a procedure and its resulting definition are physicallyjustified by a property of quantum causal sets that meets Finkelstein's requirementfor 'quantum causality' to be an immediate, as well as an algebraically represented,relation between events for discrete locality's sake. The quantum causal setsintroduced here are shown to have this property by direct use of a result fromthe algebraization of finitary topological spaces due to Breslav, Parfionov, andZapatrin.     

A mathematical characterization of the physical structure of observers

It is proposed that the physical structure of an observer in quantum mechanics is constituted by a pattern of elementary localized switching events. A key preliminary step in giving mathematical expression to this proposal is the introduction of an equivalence relation on sequences of spacetime sets which relates a sequence to any other sequence to which it can be deformed without change of causal arrangement. This allows an individual observer to be associated with a finite structure. The identification of suitable switching events in the human brain is discussed. A definition is given for the sets of sequences of quantum states which such an observer could occupy. Finally, by providing an a priori probability for such sets, the definitions are incorporated into a complete mathematical framework for a many-worlds interpretation. At a less ambitious level, the paper can be read as an exploration of some of the technical and conceptual difficulties involved in constructing such a framework.     

Absence of Singular Continuous Diffraction for Discrete Multi-Component Particle Models

Particle models with finitely many types of particles are considered, both on ℤ ^d and on discrete point sets of finite local complexity. Such sets include many standard examples of aperiodic order such as model sets or certain substitution systems. The particle gas is defined by an interaction potential and a corresponding Gibbs measure. Under some reasonable conditions on the underlying point set and the potential, we show that the corresponding diffraction measure almost surely exists and consists of a pure point part and an absolutely continuous part with continuous density. In particular, no singular continuous part is present.     

New q‐Hermite polynomials: characterization,operators algebra and associated coherent states

This paper addresses a construction of new q‐Hermite polynomials with a full characterization of their main properties and corresponding raising and lowering operator algebra. The three‐term recursive relation as well as the second‐order differential equation obeyed by these new polynomials are explicitly derived. Relevant operator actions, including the eigenvalue problem of the deformed oscillator and the self‐adjointness of the related position and momentum operators, are investigated and analyzed. The associated coherent states are constructed and discussed with an explicit resolution of the induced moment problem. The phase collapse in a q‐deformed boson system is studied.     

Scaling behaviour of lattice animals at the upper critical dimension

We perform numerical simulations of the lattice-animal problem at the upper critical dimension d = 8 on hypercubic lattices in order to investigate logarithmic corrections to scaling there. Our stochastic sampling method is based on the pruned-enriched Rosenbluth method (PERM), appropriate to linear polymers, and yields high statistics with animals comprised of up to 8000 sites. We estimate both the partition sums (number of different animals) and the radii of gyration. We re-verify the Parisi-Sourlas prediction for the leading exponents and compare the logarithmic-correction exponents to two partially differing sets of predictions from the literature. Finally, we propose, and test, a new Parisi-Sourlas-type scaling relation appropriate for the logarithmic-correction exponents.     

Physical axiomatics: Freudenthal vs. Bunge

The following remarks are intended to show that some of Freudenthal's recent criticisms of Bunge'sFoundations of Physics are wide of the mark. Freudenthal sets his criticisms of detail in a framework of some general considerations of the role played by axiomatic theories in the foundations of physics. In particular, he considers the notion of the objects of an axiomatic theory, the relation of an axiomatic theory to reality, and the notion of the transformation group of a theory. These topics are considered below.     

Q-Systems, Heaps, Paths and Cluster Positivity

We consider the cluster algebra associated to the Q-system for A _r as a tool for relating Q-system solutions to all possible sets of initial data. Considered as a discrete integrable dynamical system, we show that the conserved quantities are partition functions of hard particles on certain weighted graphs determined by the choice of initial data. This allows us to interpret the solutions of the system as partition functions of Viennot’s heaps on these graphs, or as partition functions of weighted paths on dual graphs. The generating functions take the form of finite continued fractions. In this setting, the cluster mutations correspond to local rearrangements of the fractions which leave their final value unchanged. Finally, the general solutions of the Q-system are interpreted as partition functions for strongly non-intersecting families of lattice paths on target lattices. This expresses all cluster variables as manifestly positive Laurent polynomials of any initial data, thus proving the cluster positivity conjecture for the A _r Q-system. We also give the relation to domino tilings of deformed Aztec diamonds with defects.     

Measures Defined on Quantum Logics of Sets

We study families formed with subsets of any set X which are quantum logics but which are not Boolean algebras. We consider sequences of measures defined on a sets quantum logics and valued on an effect algebra and obtain a sufficient condition for a sequences of such measures to be uniformly strongly additive with respect to order topology of effect algebras.     

Linear cellular automata and recurring sequences in finite fields

A one-dimensional linear cellular automaton with periodic boundary conditions consists of a lattice of sites on a cylinder evolving according to a linear local interaction rule. Limit cycles for such a system are studied as sets of strings on which the rule acts as a shift of sizes/h; i.e., each string in the limit cycle cyclically shifts bys sites inh iterations of the rule. For any given rule, the size of the shift varies with the cylinder sizen. The analysis of shifts establishes an equivalence between the strings of values appearing in limit cycles for these automata, and linear recurring sequences in finite fields. Specifically, it is shown that a string appears in a limit cycle for a linear automaton rule on a cylinder sizen iff its values satisfy a linear recurrence relation defined by the shift value for thatn. The rich body of results on recurring sequences and finite fields can then be used to obtain detailed information on periodic behavior for these systems. Topics considered here include the inverse problem of identifying the set of linear automata rules for which a given string appears in a limit cycle, and the structure under operations (such as addition and complementation) of sets of limit cycle strings.     

T ∞-Fuzzy observables

Observables are defined as homomorphisms from the Borel-algebra into a family of fuzzy sets considered with respect to the Giles connectives. Algebraic operations with observables are introduced and their relation to the corresponding operations with fuzzy random variables is explained.     

Relative Equilibria in Continuous Stellar Dynamics

We study a three dimensional continuous model of gravitating matter rotating at constant angular velocity. In the rotating reference frame, by a finite dimensional reduction, we prove the existence of non-radial stationary solutions whose supports are made of an arbitrarily large number of disjoint compact sets, in the low angular velocity and large scale limit. At first order, the solutions behave like point particles, thus making the link with the relative equilibria in N-body dynamics.     

On unified field theories,dynamical torsion and geometrical models: II

We analyze in this letter the same space-time structure as that presented in our previous reference (Part. Nucl., Lett. 2010. V. 7, No. 5, P. 299–307), but relaxing now the condition a priori of the existence of a potential for the torsion. We show through exact cosmological solutions from this model, where the geometry is Euclidean R ⊗ O ₃ ∼ R ⊗ SU(2), the relation between the space-time geometry and the structure of the gauge group. Precisely this relation is directly connected with the relation between the spin and torsion fields. The solution of this model is explicitly compared with our previous ones and we find that: (i) the torsion is not identified directly with the Yang-Mills type strength field, (ii) there exists a compatibility condition connected with the identification of the gauge group with the geometric structure of the space-time: this fact leads to the identification between derivatives of the scale factor with the components of the torsion in order to allow the Hosoya-Ogura ansatz (namely, the alignment of the isospin with the frame geometry of the space-time), and (iii) of two possible structures of the torsion the “tratorial” form (the only one studied here) forbids wormhole configurations, leading only to cosmological space-time solution in eternal expansion.     

Isotope shifts in finite nuclei and the pairing properties of nuclear matter

A uniform nuclear matter with s-wave pairing is studied within the local energy-density functional approach, incorporating a few parameter sets extracted from the analysis of isotope shifts in finite nuclei. The dilute limit, in which the regime changes from weak to strong pairing, is considered in detail, and, for strong coupling, the ground state properties of that system are found to be completely determined in leading order by the singlet scattering length a _nn . The combination of a density-dependent contact pairing interaction and an energy cutoff adjusted to produce a realistic value of a _nn is shown to be the preferred choice among the deduced parameter sets. Pis’ma Zh. éksp. Teor. Fiz. 70, No. 4, 235–241 (25 August 1999) Published in English in the original Russian journal. Edited by Steve Torstveit.     

Hausdorff dimension of order preserving sets

Letg aC ² generic bimodal map of the circle. We prove that the closure of the union of the order preserving recurrent sets with irrational rotation number has Hausdorff dimension zero. This set contains order preserving periodic orbits with each rotation numberp/q in the rotation interval ofg.     

Contractions, Deformations and Curvature

The role of curvature in relation with Lie algebra contractions of the pseudo-orthogonal algebras so(p,q) is fully described by considering some associated symmetrical homogeneous spaces of constant curvature within a Cayley–Klein framework. We show that a given Lie algebra contraction can be interpreted geometrically as the zero-curvature limit of some underlying homogeneous space with constant curvature. In particular, we study in detail the contraction process for the three classical Riemannian spaces (spherical, Euclidean, hyperbolic), three non-relativistic (Newtonian) spacetimes and three relativistic ((anti-)de Sitter and Minkowskian) spacetimes. Next, from a different perspective, we make use of quantum deformations of Lie algebras in order to construct a family of spaces of non-constant curvature that can be interpreted as deformations of the above nine spaces. In this framework, the quantum deformation parameter is identified as the parameter that controls the curvature of such “quantum” spaces.     

Some remarks about the localization of states in a quantum field theory

For the case of a field theory with a nuclear space of test functions (for instance, the space of strongly decreasing test functions) compact sets of states are constructed; these correspond to sets of localized states. Only such states are considered which are elements of a fixed subspace of the entire Hilbert space. This subspace belongs to them-point functions of order less than a certain fixed 2n.Supported in part by the Air Force Office of Scientific Research under Grant AF 500–64On leave of absence from the Max Planck-Institut für Physik und Astrophysik, München.