Towards a quantum field theory of primitive string fields

We denote generating functions of massless even higher spin fields "primitive string fields" (PSF's). In an introduction we present the necessary definitions and derive propagators and currents of these PDF's on flat space. Their off-shell cubic interaction can be derived after all off-shell cubic interactions of triplets of higher spin fields have become known [2],[3]. Then we discuss four-point functions of any quartet of PSF's. In subsequent sections we exploit the fact that higher spin field theories in $AdS_{d+1}$ are determined by AdS/CFT correspondence from universality classes of critical systems in $d$ dimensional flat spaces. The O(N) invariant sectors of the O(N) vector models for $1\leq N \leq \infty$ play for us the role of "standard models", for varying $N$, they contain e.g. the Ising model for N=1 and the spherical model for $N=\infty$. A formula for the masses squared that break gauge symmetry for these O(N) classes is presented for d = 3. For the PSF on $AdS$ space it is shown that it can be derived by lifting the PSF on flat space by a simple kernel which contains the sum over all spins. Finally we use an algorithm to derive all symmetric tensor higher spin fields. They arise from monomials of scalar fields by derivation and selection of conformal (quasiprimary) fields. Typically one monomial produces a multiplet of spin $s$ conformal higher spin fields for all $s \geq 4$, they are distinguished by their anomalous dimensions (in $CFT_3$) or by their mass (in $AdS_4$). We sum over these multiplets and the spins to obtain "string type fields", one for each such monomial.Comment: 16 pages,Late

Regularization and finiteness of the Lorentzian LQG vertices

We give an explicit form for the Lorentzian vertices recently introduced for possibly defining the dynamics of loop quantum gravity. As a result of so doing, a natural regularization of the vertices is suggested. The regularized vertices are then proven to be finite. An interpretation of the regularization in terms of a gauge-fixing is also given.Comment: 16 pages; Added an appendix presenting the gauge-fixing interpretation, added three references, and made some minor change

Descent Relations in Cubic Superstring Field Theory

The descent relations between string field theory (SFT) vertices are characteristic relations of the operator formulation of SFT and they provide self-consistency of this theory. The descent relations and in the NS fermionic string field theory in the kappa and discrete bases are established. Different regularizations and schemes of calculations are considered and relations between them are discussed.Comment: Replaced to JHEP styl

Probing Crystallinity and Grain Structure of 2D Materials and 2D-Like Van der Waals Heterostructures by Low-Voltage Electron Diffraction

4D scanning transmission electron microscopy (4D-STEM) is a powerful method for characterizing electron-transparent samples with down to sub-Ångstrom spatial resolution. 4D-STEM can reveal local crystallinity, orientation, grain size, strain, and many more sample properties by rastering a convergent electron beam over a sample area and acquiring a transmission diffraction pattern (DP) at each scan position. These patterns are rich in information about the atomic structure of the probed volume, making this technique a potent tool to characterize even inhomogeneous samples. 4D-STEM can also be used in scanning electron microscopes (SEMs) by placing an electron-sensitive camera below the sample. 4D-STEM-in-SEMs is ideally suited to characterize 2D materials and 2D-like van der Waals heterostructures (vdWH) due to their inherent thickness of a few nanometers. The lower accelerating voltage of SEMs leads to strong scattering even from monolayers. The large field of view and down to sub-nm spatial resolution of SEMs are ideal to map properties of the different constituents of 2D-like vdWH by probing their combined sample volume. A unique 4D-STEM-in-SEM system is applied to reveal the single crystallinity of MoS2 exfoliated with gold-mediation as well as the crystal orientation and coverage of both components of a C60/MoS2 vdWH are determined

Exact solutions for interacting boson systems under rotation

We study a class of interacting, harmonically trapped boson systems at angular momentum L. The Hamiltonian leaves a L-dimensional subspace invariant, and this permits an explicit solution of several eigenstates and energies for a wide class of two-body interactionsComment: 8 pages, error corrected (concerns generalization of subspace structure

Timelike surfaces in Lorentz covariant loop gravity and spin foam models

We construct a canonical formulation of general relativity for the case of a timelike foliation of spacetime. The formulation possesses explicit covariance with respect to Lorentz transformations in the tangent space. Applying the loop approach to quantize the theory we derive the spectrum of the area operator of a two-dimensional surface. Its different branches are naturally associated to spacelike and timelike surfaces. The results are compared with the predictions of Lorentzian spin foam models. A restriction of the representations labeling spin networks leads to perfect agreement between the states as well as the area spectra in the two approaches.Comment: a wrong sign corrected in equation (65

An exactly solvable three-particle problem with three-body interaction

The energy spectrum of the three-particle Hamiltonian obtained by replacing the two-body trigonometric potential of the Sutherland problem by a three-body one of a similar form is derived. When expressed in appropriate variables, the corresponding wave functions are shown to be expressible in terms of Jack polynomials. The exact solvability of the problem with three-body interaction is explained by a hidden sl(3,\R) symmetry.Comment: LaTeX, 15 pages, no figures, slightly shortened version to appear in Phys. Rev. A, one error correcte

Attosecond streaking metrology with isolated nanotargets

The development of attosecond metrology has enabled time-resolved studies on atoms, molecules, and (nanostructured) solids. Despite a wealth of theoretical work, attosecond experiments on isolated nanotargets, such as nanoparticles, clusters, and droplets have been lacking. Only recently, attosecond streaking metrology could be extended to isolated silica nanospheres, enabling real-time measurements of the inelastic scattering time in dielectric materials. Here, we revisit these experiments and describe the single-shot analysis of velocity-map images, which permits to evaluate the recorded number of electrons. Modeling of the recorded electron histograms allows deriving the irradiated nanoparticle statistics. Theoretically, we analyze the influence of the nanoparticle size on the field-induced delay, which is one of the terms contributing to the measured streaking delay. The obtained new insight into attosecond streaking experiments on nanoparticles is expected to guide wider implementation of the approach on other types of nanoparticles, clusters, and droplets

On the broken gauge, conformal and discrete symmetries in particle physics

Relationships between gauge, conformal and discrete symmetries in particle physics are analysed. We study also the effect of the electroweak mixing on the cancellation of SU(2) anomalous actions. It is shown that the relation theta_{W} = 2(theta_{12}+theta_{23}+theta_{13}) between the Weinberg angle and the Cabibbo-Kobayashi-Maskawa angles should be satisfied and this effect is completely defined by the mixing of Dirac fermions. We compare two mechanisms of the spontaneous breaking of gauge symmetry, discuss the renormalizability of theories, and argue for the existence of the Majorana fermions necessary to remove the SU(2) anomalous action. The fate of the majoron and the spontaneously broken lepton number is discussed. We also show the compatibility of the boson and fermion mixings with Dyson-Schwinger equations.Comment: 27 pages, LaTeX style; v2: published version, two figures adde