arXiv subjects

C. Furey

Publications and source records attributed to C. Furey.

5 recordsLinked to original sources

arXiv2026

The incidence of LBV variability in the LMC

Luminous blue variables (LBVs) exhibit unique variability features, characterized by episodic outbursts ($>$1 mag) accompanied by spectroscopic changes (S Dor variables). It is debated if all massive stars undergo an LBV-like phase during their evolution, or instead LBVs are exotic phenomena. We aim to quantify the incidence of LBV-like variability in the blue supergiant (BSgs) population of the Large Magellanic Cloud (LMC) using the OGLE survey. Here, we extend previous work in the Small Magellanic Cloud to the LMC, where we examine the light curves of 87 B Supergiants (BSgs) (out of 254 known BSgs) spanning timescales of twenty years, and 37 objects across a three year timescale for aperiodic variations resembling known S Dor variables. One blue supergiant, [ST92] 4-13 shows S Dor type photometric variations. New spectra of this object reveals a potential change in spectral type compared to the literature classification. However, based on its spectral characteristics and low luminosity and mass, we do not currently classify it as an LBV. Our study highlights the need to classify bona fide LBVs as stars undergoing both photometric and spectroscopic variations. Based on currently known stellar population of S Dor variables in the LMC, the lifetime of the S Dor phase is at most $\sim$10$^3$ yrs, in agreement with our duty cycle study based on OGLE data in the SMC. This is orders of magnitude shorter than assumed in literature. Our discovery of LBV-like variability at low luminosities may suggest that S Dor variations could arise from Eddington limit related physics over a wide range of stellar masses, rather than being linked to a unique evolutionary stage.

astro-ph.SR↗

arXiv2018

Charge quantization from a number operator

We explain how an unexpected algebraic structure, the division algebras, can be seen to underlie a generation of quarks and leptons. From this new vantage point, electrons and quarks are simply excitations from the neutrino, which formally plays the role of a vacuum state. Using the ladder operators which exist within the system, we build a number operator in the usual way. It turns out that this number operator, divided by 3, mirrors the behaviour of electric charge. As a result, we see that electric charge is quantized because number operators can only take on integer values. Finally, we show that a simple hermitian form, built from these ladder operators, results uniquely in the nine generators of $SU(3)_c$ and $U(1)_{em}$. This gives a direct route to the two unbroken gauge symmetries of the standard model.

hep-th↗

arXiv2018

$SU(3)_C\times SU(2)_L\times U(1)_Y\left( \times U(1)_X \right)$ as a symmetry of division algebraic ladder operators

We demonstrate a model which captures certain attractive features of $SU(5)$ theory, while providing a possible escape from proton decay. In this paper we show how ladder operators arise from the division algebras $\mathbb{R}$, $\mathbb{C}$, $\mathbb{H}$, and $\mathbb{O}$. From the $SU(n)$ symmetry of these ladder operators, we then demonstrate a model which has much structural similarity to Georgi and Glashow's $SU(5)$ grand unified theory. However, in this case, the transitions leading to proton decay are expected to be blocked, given that they coincide with presumably forbidden transformations which would incorrectly mix distinct algebraic actions. As a result, we find that we are left with $G_{sm} = SU(3)_C\times SU(2)_L\times U(1)_Y / \mathbb{Z}_6$. Finally, we point out that if $U(n)$ ladder symmetries are used in place of $SU(n)$, it may then be possible to find this same $G_{sm}=SU(3)_C\times SU(2)_L\times U(1)_Y / \mathbb{Z}_6$, together with an extra $U(1)_X$ symmetry, related to $B-L$.

hep-th↗

arXiv2018

Towards a unified theory of ideals

Unified field theories act to merge the internal symmetries of the standard model into a single group. Here we lay out something different. That is, instead of aiming to unify the internal symmetries, we demonstrate a sense in which the group transformations may be unified with the quarks and leptons that they act on. Similarly, the (3+1) Lorentz transformations may be united with the scalars, spinors, four-vectors and field strength tensors that they act on. These simplifications occur because the representations can be found in the form of an algebra acting on itself. The approach described in this paper is meant to tie everything into the Dixon algebra: $\mathbb{R}\otimes\mathbb{C}\otimes\mathbb{H}\otimes\mathbb{O}$, the tensor product of the only four normed division algebras over $\mathbb{R}$. Here we demonstrate that the standard model's Lorentz representations may be cast as a special set of generalized ideals within the algebra $\mathbb{C}\otimes\mathbb{H}$. We then make an early attempt at extending this idea to one generation of quarks and leptons.

hep-th↗

arXiv2016

Standard model physics from an algebra?

This thesis constitutes a first attempt to derive aspects of standard model particle physics from little more than an algebra. Here, we argue that physical concepts such as particles, causality, and irreversible time may result from the algebra acting on itself. We then focus on a special case by considering the algebra $\mathbb{R}\otimes\mathbb{C}\otimes\mathbb{H}\otimes\mathbb{O}$. Using nothing more than $\mathbb{R}\otimes\mathbb{C}\otimes\mathbb{H}\otimes\mathbb{O}$ acting on itself, we set out to find standard model particle representations. From the complex quaternionic portion of the algebra, we find generalized ideals, and show that they describe concisely all of the Lorentz representations of the standard model. From the complex octonionic portion of the algebra, we find minimal left ideals, and show that they mirror the behaviour of a generation of quarks and leptons under $su(3)_c$ and $u(1)_{em}$. We then demonstrate a rudimentary electroweak model which yields a straightforward explanation as to why $SU(2)_L$ acts only on left-handed states. This holds in the case of leptons. Finally, we demonstrate how $\mathbb{C}\otimes\mathbb{O}$ can generate a 64-$\mathbb{C}$-dimensional algebra, wherein we find the $SU(3)_c$ irreducible representations corresponding to three generations of quarks and leptons. We then conclude by showing how to arrive at all 48 electric charges.

hep-th↗