SearcharxivSearch

arXiv subjects

Jiheon Lee

Publications and source records attributed to Jiheon Lee.

10 recordsLinked to original sources

High-Frequency Gravitational Waves from Phase Transitions in Nascent Neutron Stars

Tentative evidence suggests that the cores of massive neutron stars consist of deconfined quark matter. We argue that the formation of such a quark matter core during a galactic supernova could be accompanied by the emission of gravitational waves in the MHz band. These signals constitute a new target for high-frequency gravitational wave detectors, demonstrating that such detectors may offer unique opportunities for testing quantum chromodynamics in an otherwise inaccessible regime.

hep-ph

GlueNN: gluing patchwise analytic solutions with neural networks

In the analysis of complex physical systems, the objective often extends beyond merely computing a numerical solution to capturing the precise crossover between different regimes and extracting parameters containing meaningful information. However, standard numerical solvers and conventional deep learning approaches, such as Physics-Informed Neural Networks (PINNs), typically operate as black boxes that output solution fields without disentangling the solution into its interpretable constituent parts. In this work, we propose GlueNN, a physics-informed learning framework that decomposes the global solution into interpretable, patchwise analytic components. Rather than approximating the solution directly, GlueNN promotes the integration constants of local asymptotic expansions to learnable, scale-dependent coefficient functions. By constraining these coefficients with the differential equation, the network effectively performs regime transition, smoothly interpolating between asymptotic limits without requiring ad hoc boundary matching. We demonstrate that this coefficient-centric approach reproduces accurate global solutions in various examples and thus directly extracts physical information that is not explicitly available through standard numerical integration.

cs.LG

BCS superconductivity in the presence of wave dark matter

In the established era of dark matter, condensed matter Hamiltonians-including those of superconductors-may require extension to account for the surrounding Galactic environment. We show that if dark matter is wave-like and couples weakly to electrons, superconducting parameters such as the gap and critical temperature become dynamical quantities that oscillate in time. This modifies the Bardeen-Cooper-Schrieffer framework and produces distinctive temporal signatures whose sensitivity increases with longer measurement durations. Our results illustrate how condensed matter systems, traditionally treated as isolated from their cosmological environment, may acquire new dynamical degrees of freedom from their cosmic embedding. This, in turn, offers a novel window into the dark sector.

hep-ph

Dark energy under a gauge symmetry: A review of gauged quintessence and its implications

We review the gauged quintessence scenario, wherein the quintessence scalar field responsible for dark energy is promoted to a complex field charged under a dark $U(1)$ gauge symmetry. This construction leads to new and potentially rich cosmological phenomenology. After a concise recap of the standard quintessence scenario, we highlight how a $U(1)$ gauge invariance alters the dynamics of the scalar and the associated dark gauge boson. We survey the evolution of both fields across cosmic history, discuss their possible production via a misalignment mechanism, and examine implications for the Hubble tension. We also comment on potential non-gravitational signals of gauged quintessence through kinetic mixing (the dark photon vector portal).

hep-ph

Dark gauge-mediated supersymmetry breaking with a massless dark photon

We study dark gauge-mediated supersymmetry breaking (dark GMSB) in a theory with a new unbroken $U(1)_{D}$ local symmetry and massless dark photon. Messenger fields charged under both Standard Model and dark gauge symmetries produce new soft supersymmetry-breaking terms due to gauge kinetic mixing between $U(1)_Y$ hypercharge and $U(1)_D$. We show that large kinetic mixing induces significant distortions to the superpartner spectra relative to conventional GMSB. Notably, shifts in the Higgs soft masses impact the conditions for electroweak symmetry breaking, lowering the $μ$ parameter and yielding a relatively light Higgsino that may be accessible at the LHC. Furthermore, for very simple messenger representations, a very light bino-dark photino mixed state is present in the spectrum, which may be probed through exotic Higgs boson decays at future Higgs factories. We also examine the cosmological and phenomenological consequences of the messengers, the lightest of which is absolutely stable and carries fractional electric charge.

hep-ph

Non-gravitational signals of dark energy under a gauge symmetry

We investigate non-gravitational signals of dark energy within the framework of gauge symmetry in the dark energy sector. Traditionally, dark energy has been primarily studied through gravitational effects within general relativity or its extensions. On the other hand, the gauge principles have played a central role in the standard model sector and dark matter sector. If the dark energy field operates under a gauge symmetry, it introduces the possibility of studying all major components of the present universe under the same gauge principle. This approach marks a significant shift from conventional methodologies, offering a new avenue to explore dark energy.

astro-ph.CO

Searching for new physics effects in future $W$ mass and $\sin^2θ_W (Q^2)$ determinations

We investigate the phenomenology of the dark $Z$ boson, $Z_d$, which is associated with a new Abelian gauge symmetry and couples to the standard model particles via kinetic mixing $\varepsilon$ and mass mixing $\varepsilon_Z^{}$. We examine two cases: (i) $Z_d$ is lighter than the $Z$ boson, and (ii) $Z_d$ is heavier than that. In the first case, it is known that $Z_d$ causes a deviation in the weak mixing angle at low energies from the standard model prediction. We study the prediction in the model and compare it with the latest experimental data. In the second case, the $Z$-$Z_d$ mixing enhances the $W$ boson mass. We investigate the effect of $Z_d$ on various electroweak observables including the $W$ boson mass using the $S$, $T$, and $U$ parameters. We point out an interesting feature: in the limit $\varepsilon \to 0$, the equation $S = - U$ holds independently of the mass of $Z_d$ and the size of $\varepsilon_Z^{}$, while $|S|\gg |U|$ in many new physics models. We find that the dark $Z$ boson with a mass of $O(100)~\mathrm{GeV}$ with a relatively large mass mixing can reproduce the CDF result within $2σ$ while avoiding all other experimental constraints. Such dark $Z$ bosons are expected to be tested at future high-energy colliders.

hep-ph

Misalignment mechanism for a mass-varying vector boson

A coherent field over the entire universe is an attractive picture in studying the dark sector of the universe. The misalignment mechanism, which relies on inflation to achieve homogeneousness of the field, is a popular mechanism for producing such a coherent dark matter. Nevertheless, unlike a scalar field case, a vector boson field suffers because its energy density is exponentially suppressed by the scale factor during the cosmic expansion. We show that if the vector field gets a mass from a scalar field, whose value increases by orders of magnitude, the suppression can be compensated, and the misalignment can produce the coherent vector boson that has a sizable amount of energy density in the present universe. Quintessence can be such a scalar field.

astro-ph.CO

Gauged Quintessence

Despite its dominance in the present universe's energy budget, dark energy is the least understood component in the universe. Although there is a popular model for the dynamical dark energy, the quintessence scalar, the investigation is limited because of its highly elusive character. We present a model where the quintessence is gauged by an Abelian gauge symmetry. The quintessence is promoted to be a complex scalar whose real part is the dark energy field while the imaginary part is the longitudinal component of a new gauge boson. It brings interesting characters to dark energy physics. We study the general features of the model, including how the quintessence behavior is affected and how the solicited dark energy properties constrain its gauge interaction. We also note that while the uncoupled quintessence models are suffered greatly from the Hubble tension, it can be alleviated if the quintessence is under the gauge symmetry.

astro-ph.CO

Subfrequency search at a laser as a signal of dark matter sector particles

We introduce a new method to search for the dark matter sector particles using laser light. Some dark matter particles may have a small mixing or interaction with a photon. High-power lasers provide substantial test grounds for these hypothetical light particles of exploding interests in particle physics. We show that any light source can also emit a subfrequency light as a new physics signal. Searching for this subfrequency light at a laser can be a simple and effective way to investigate the new light particles, even in tabletop optics experiments.

hep-ph