Automatic Dish Name Extraction from User-generated Content Using LLM

Extraction of dish names from user-provided content such as food photographs and captions, restaurant reviews, and other free-form text is a challenging task. Rule-based approaches are difficult to maintain and improve. Pattern matching against a predefined dictionary often suffers from low recall. Conventional machine learning models require large amounts of labeled data to perform named entity recognition (e.g., to recognize dish names) which is often costly and does not scale well across multiple languages and countries. This disclosure describes the use of a multimodal large language model to automatically extract dish names from user-generated content such as food photographs and associated free-form text such as tags, captions, etc. Dish name extraction from the user-provided tags can be formulated as an open vocabulary dish name entity recognition and discovery task, which fits naturally with the framework of pre-trained LLMs, and leverages the model capability in handling multilingual, multicultural text understanding

Gamma-ray emission from rotation-powered pulsars

Using a simplified model of cascade pair creation over pulsar polar caps presented in two previous papers, we investigate the expected gamma-ray output from pulsars' low altitude particle acceleration and pair creation regions. We divide pulsars into several categories, based on which mechanism truncates the particle acceleration off the polar cap, and give estimates for the expected luminosity of each category. We find that inverse Compton scattering above the pulsar polar cap provides the primary gamma rays which initiate the pair cascades in most pulsars. This reduces the expected $\gamma$-ray luminosity below previous estimates which assumed curvature gamma ray emission was the dominant initiator of pair creation in all pulsars.Comment: 10 pages, 5 figures, to be published in Ap

Pair Multiplicities and Pulsar Death

Through a simple model of particle acceleration and pair creation above the polar caps of rotation-powered pulsars, we calculate the height of the pair-formation front (PFF) and the dominant photon emission mechanism for the pulsars in the Princeton catalog. We find that for most low- and moderate-field pulsars, the height of the pair formation front and the final Lorentz factor of the primary beam is set by nonresonant inverse Compton scattering (NRICS), in the Klein-Nishina limit. NRICS is capable of creating pairs over a wide range of pulsar parameters without invoking a magnetic field more complicated than a centered dipole, although we still require a reduced radius of curvature for most millisecond pulsars. For short-period pulsars, the dominant process is curvature radiation, while for extremely high-field pulsars, it is resonant inverse Compton scattering (RICS). The dividing point between NRICS dominance and curvature dominance is very temperature-dependent; large numbers of pulsars dominated by NRICS at a stellar temperature of $10^6$ K are dominated by curvature at $10^5$ K. We apply these results to pulsar death-line calculations and to the issue of particle injection into the Crab Nebula.Comment: 14 pages, 7 figures, to appear in Ap

Pair-production multiplicities in rotation-powered pulsars

We discuss the creation of electron-positron cascades in the context of pulsar polar cap acceleration models and derive several useful analytic and semi-analytic results for the spatial extent and energy response of the cascade. Instead of Monte Carlo simulations, we use an integro- differential equation which describes the development of the cascade energy spectrum in one space dimension quite well, when it is compared to existing Monte Carlo models. We reduce this full equation to a single integral equation, from which we can derive useful results, such as the energy loss between successive generations of photons and the spectral index of the response. We find that a simple analytic formula represents the pair cascade multiplicity quite well, provided that the magnetic field is below 10^12 Gauss, and that an only slightly more complex formula matches the numerically-calculated cascade at all other field strengths. Using these results, we find that cascades triggered by gamma rays emitted through inverse Compton scattering of thermal photons from the neutron star's surface, both resonant and non-resonant, are important for the dynamics of the polar cap region in many pulsars.Comment: to appear in ApJ; 19 pages, 18 figure

Polarization Sweeps in Rotation Powered Pulsars

We re-examine the characteristic polarization angle sweep of rotation-powered pulsars and calculate the expected deviations from this sweep caused by aberrational effects and by polar-cap current flow. We find that in addition to the previously known phase shift of the entire sweep by $\Delta \Phi = -4 r/R_L$, aberration shifts the polarization angle itself by $\Delta \Psi = -(10/3) (r/R_L) \cos \alpha$. Similarly, current flow above the polar cap shifts the polarization sweep by $\Delta \Psi = (10/3) (r/R_L) (J/J_{GJ}) \cos \alpha$, potentially providing a method of directly measuring the magnitude of the current. The competition between these two effects produces a potentially observable signature in the polarization angle sweep. Although these effects may appear similar to orthogonal mode shifts, they are an independent phenomenon with distinct observational characteristics.Comment: 23 pages, 8 figures; accepted by Ap