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Vi Hong

Publications and source records attributed to Vi Hong.

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Tropical Open Strings in a Kalb-Ramond Background

We study tropical open strings arising from the analytically continued action of tropological sigma models in the presence of a constant Kalb-Ramond background. We show that the background field separates the theory into a generic sector and a critical sector. In the generic sector, the canonical structure produces a kinematical nonlocal bracket between the transverse and leafwise target-space coordinates. At the critical value of the Kalb-Ramond field, the Legendre map degenerates and the theory develops a primary constraint, requiring quantization by the Dirac-Bergmann procedure. This critical sector has a finite reduced phase-space structure and differs from the naive limit of the generic theory.

hep-th

Tropical Limits of Dirac Operators

We explore the tropical analog of spinors by representing tropical geometries as foliated Riemann surfaces endowed with degenerate complex structures. We investigate tropical limits of the Laplace-Beltrami operator and explicitly construct its square root, which defines a tropical Dirac operator. We find that the tropical Clifford algebra is classified as a degenerate Clifford algebra with nilpotent generators. The nilpotent generator allows us to work with a new kind of representation that allows for Grassmann odd numbers, effectively supersymmetrizing the tropical spin bundle. We show through Dirac-Bergmann's quantization procedure, that the corresponding tropicalized quantum field theories enjoy a purely fermionic topological symmetry which can be expected to give a new class of path integral localization that we call tropical localization similar to the alternative localization method recently constructed by Choi and Takhtajan. We also discuss how the tropical Dirac operator, when twisted by gauge fields, obeys a tropical version of the Lichnerowicz identity, thereby demonstrating how some elements of Yang-Mills curvature should arise in the tropical limit.

hep-th

A Tropical Look at Coisotropic Branes and Quantization

We continue our investigation of tropical branes by exploring the tropicalization of topological sigma models with boundaries. We show that the tropical limit naturally decomposes conventional A-branes into two distinct classes: tropical Lagrangian branes and tropical coisotropic branes. By carefully analyzing the modified boundary conditions emerging from the tropological sigma models, we construct these tropical branes explicitly and demonstrate their utility in an example where we quantize a symplectic manifold through the use of a tropical version of brane quantization.

hep-th

Tropical Branes

We investigate canonically quantized open string solutions associated to the analytically continued action for the recently proposed tropical limit of topological A-type models, tropological sigma models, with various boundary conditions. These solutions naturally give rise to a non-relativistic counterpart of branes, which we name tropical branes. We provide a preliminary worldsheet description of these tropical branes, laying the groundwork for an upcoming paper that will explore the role of tropical branes in the context of brane quantization.

hep-th

Search for Axions from Magnetic White Dwarfs with Chandra

Low mass axion-like particles could be produced in abundance within the cores of hot, compact magnetic white dwarf (MWD) stars from electron bremsstrahlung and converted to detectable X-rays in the strong magnetic fields surrounding these systems. In this work, we constrain the existence of such axions from two dedicated Chandra X-ray observations of $\sim$40 ks each in the energy range $\sim$1 - 10 keV towards the magnetic white dwarfs (MWDs) WD 1859+148 and PG 0945+246. We find no evidence for axions, which constrains the axion-electron times axion-photon coupling to $|g_{a\gamma \gamma} g_{aee}| \lesssim 1.54 \times 10^{-25}$ ($3.54 \times 10^{-25}$) GeV$^{-1}$ for PG 0945+246 (WD 1859+148) at 95% confidence for axion masses $m_a \lesssim 10^{-6}$ eV. We find an excess of low-energy X-rays between 1 - 3 keV for WD 1859+148 but determine that the spectral morphology is too soft to arise from axions; instead, the soft X-rays may arise from non-thermal emission in the MWD magnetosphere.

astro-ph.HE