International Journal of Modern Physics A

In this paper the problem of constructing space–time from string theory is addressed in the context of D-brane physics. It is suggested that the knowledge of discrete configurations of D-branes is sufficient to reconstruct the motivic building blocks of certain Calabi–Yau varieties. The collections of D-branes involved have algebraic base points, leading to the notion of K-arithmetic D-crystals for algebraic number fields K. This idea can be tested for D0-branes in the framework of toroidal compactifications via the conjectures of Birch and Swinnerton-Dyer. For the special class of D0-crystals of Heegner type these conjectures can be interpreted as formulae that relate the canonical Néron–Tate height of the base points of the D-crystals to special values of the motivic L-function at the central point. In simple cases the knowledge of the D-crystals of Heegner type suffices to uniquely determine the geometry.

Massive p-forms are analyzed from the point of view of the Hamiltonian path integral quantization. More precisely, the quantization procedure is based on the path integral of a first-class system equivalent (at both classical and quantum levels) with the original theory. This first-class system is constructed using the gauge unfixing approach and the Batalin–Fradkin method, respectively. Both methods finally output the manifestly Lorentz covariant path integral for p- and (D-p-1)-forms with topological coupling or (p-1)- and p-forms with Stückelberg coupling.

A new approach is employed to provide the required expressions for the bare constituent quark densities in the proton. In this approach, we assume the bare quark densities take a Gaussian form in four-momentum space, which fulfill more properly the desired constrains of parton densities inside the proton. Using the modified chiral quark model and the related convolutions, the parton densities inside the proton are obtained. By evolving the gluon density to high energy scale, the contribution of charm quark to the proton structure function can be extracted and it is found in good agreement with the available experimental data. Sea quark ((anti-)strange) densities are calculated and compared with the ones from some phenomenological and experimental groups in which consistent results are obtained. What makes the results more valuable is that the initial framework is completely theoretical and we do not need to resort to any parametrizations in our calculations.

We evolve our Multiverse Blueprints to characterize our local neighborhood of the String Landscape and the Multiverse of plausible string, M- and F-theory vacua. Building upon the tripodal foundations of (i) the Flipped SU(5) Grand Unified Theory (GUT), (ii) extra TeV-Scale vector-like multiplets derived out of F-theory, and (iii) the dynamics of No-Scale supergravity, together dubbed No-Scale , we demonstrate the existence of a continuous family of solutions which might adeptly describe the dynamics of distinctive universes. This Multiverse landscape of solutions, which we shall refer to as the -Landscape, accommodates a subset of universes compatible with the presently known experimental uncertainties of our own universe. We show that by secondarily minimizing the minimum of the scalar Higgs potential of each solution within the -Landscape, a continuous hypervolume of distinct minimum minimorum can be engineered which comprise a regional dominion of universes, with our own universe cast as the bellwether. We conjecture that an experimental signal at the LHC of the No-Scale framework's applicability to our own universe might sensibly be extrapolated as corroborating evidence for the role of string, M- and F-theory as a master theory of the Multiverse, with No-Scale supergravity as a crucial and pervasive reinforcing structure.

We investigate a possibility of scale invariant but nonconformal supersymmetric field theories from a perturbative approach. The explicit existence of monotonically decreasing a-function that generates beta-functions as a gradient flow provides a strong obstruction for such a possibility at two-loop order. We comment on the "discovery" of scale invariant but nonconformal renormalization group trajectories via a "change of scheme" in (4-ϵ) dimension proposed in literatures.

We perform the Becchi–Rouet–Stora–Tyutin (BRST) analysis of the Freedman–Townsend (FT) model of topologically massive non-Abelian theory by exploiting its (1-form) Yang–Mills (YM) gauge transformations to show the existence of some novel features that are totally different from the results obtained in such a kind of consideration carried out for the dynamical non-Abelian 2-form theory. We tap here the potential and power of the augmented version of Bonora–Tonin's superfield approach to BRST formalism to derive the full set of off-shell nilpotent and absolutely anticommuting (anti-)BRST symmetry transformations where, in addition to the horizontality condition (HC), we are theoretically compelled to exploit the appropriate gauge-invariant restrictions (GIRs) on the (super)fields for the derivation of the appropriate symmetry transformations for all the relevant fields. We compare our key results with that of the other such attempt for the discussion of the present model within the framework of BRST formalism.

We consider a process of parametric down conversion where the input state is a bosonic thermofield vacuum. This state leads to a parametric down conversion, generating an output of two excited photons. Following a thermofield dynamics scheme, the input state, initially in a bosonic thermofield vacuum, and the output states, initially in vacuum states, evolve under a Liouville–von Neumann equation.

We show that relativistic hydrodynamics in Minkowski space–time has intrinsic ambiguity in second-order viscosity parameters in the Landau–Lifshitz frame. This stems from the possibility of improvements of energy–momentum tensor. There exist at least two viscosity parameters which can be removed by using this ambiguity in scale invariant hydrodynamics in (1+3) dimension, and seemingly nonconformal hydrodynamic theories can be hiddenly conformal invariant.

It has been proposed that quantum mechanics and string theory share a common inner syntax, the relational logic of C. S. Peirce. Along this line of thought we consider the relations represented by spinors. Spinor composition leads to the emergence of Minkowski space–time. Inversely, the Minkowski space–time is istantiated by the Weyl spinors, while the merger of two Weyl spinors gives rise to a Dirac spinor. Our analysis is applied also to the string geometry. The string constraints are represented by real spinors, which create a parametrization of the string worldsheet identical to the Enneper–Weierstass representation of minimal surfaces. Further, a spinorial study of the AdS₃ space–time reveals a Hopf fibration AdS₃ → AdS₂. The conformal symmetry inherent in AdS₃ is pointed out. Our work indicates the hidden ties between logic-quantum mechanics-string theory-geometry and vindicates the Wheeler's proposal of pregeometry as a large network of logical propositions.

We investigate the spectra and decays of charmonium system in a semirelativistic potential model. The Hamiltonian of our model consists of a relativistic kinetic energy term, a vector Coulomb-like potential and a scalar confining potential. From this Hamiltonian a spinless wave equation is obtained. The wave equation is then reduced to the form of a single particle Schrödinger equation. The spin dependent potentials are introduced as a perturbation. The three-dimensional harmonic oscillator wave function is employed as a trial wave function and the mass spectra is obtained by the variational method. The model parameters and the wave function that reproduce the mass spectra of the mesons are then used to investigate some of the decay properties. The results obtained are then compared with the experimental data and with the predictions of other theoretical models. We also propose possible assignments for the recently observed charmonium or charmonium-like states.

We study analytical properties of the Stuckelberg holographic superconductors with Weyl corrections. We obtain the minimum critical temperature as a function of the mass of the scalar field m². We show that in limit of the which is close to the numerical estimate . Further we show that the mass of the scalar field is bounded from below by the where . This lower bound is weaker and different from the previous lower bound m² = -3 predicted by stability analysis. We show that in the Breitenlohner–Freedman bound, the critical temperature remains finite. Explicitly, we prove that here there exists a linear relation between 〈O_Δ〉 and the chemical potential.

We consider a pointlike two-level system undergoing uniformly accelerated motion. We evaluate the transition probability rate of this system coupled to a massless scalar field near a fluctuating event horizon. Such horizon fluctuations are generated using random noise. We study the case of centered, stationary and Gaussian random processes. The transition probability of the two-level system is obtained from the positive-frequency Wightman function calculated to one-loop order in the noise averaging process. Our results show how this fluctuating-horizon model modifies the response function of the two-level system.

We present a best-fit analysis on the single-parameter holographic dark energy model characterized by the conformal-age-like length, . Based on the Union2 compilation of 557 supernova Ia (SNIa) data, the baryon acoustic oscillation (BAO) results from the Sloan Digital Sky Survey data release 7 (SDSS DR7) and the cosmic microwave background radiation (CMB) data from the 7-year Wilkinson Microwave Anisotropy Probe (WMAP7), we show that the model gives the minimal , which is comparable to for the ΛCDM model. The single parameter d concerned in the model is found to be d = 0.232±0.006±0.009. Since the fractional density of dark energy Ω_de ~ d²a² at a ≪ 1, the fraction of dark energy is naturally negligible in the early universe, Ω_de ≪ 1 at a ≪ 1. The resulting constraints on the present fractional energy density of matter and the equation of state are and respectively. We also provide a systematic analysis on the cosmic evolutions of the fractional energy density of dark energy, the equation of state of dark energy, the deceleration parameter and the statefinder. It is noticed that the equation of state crosses from w_de > -1 to w_de < -1, the universe transits from decelerated expansion (q > 0) to accelerated expansion (q < 0) recently, and the statefinder may serve as a sensitive diagnostic to distinguish the CHDE model with the ΛCDM model.