arXiv subjects

Anirban Biswas

Publications and source records attributed to Anirban Biswas.

At least 19 recordsLinked to original sources

arXiv2026

Probing low scale leptogenesis through gravitational wave

The quest for a common origin of neutrino mass and baryogenesis is one of the longstanding goals in particle physics. A minimal gauge extension of the Standard Model by $U(1)_{\rm B-L}$ symmetry provides a unique scenario to explain the tiny mass of neutrinos as well as the observed baryon asymmetry, both by virtue of three right-handed neutrinos (RHNs). Additionally, the $U(1)_{\rm B-L}$ breaking scalar that generates mass of the RHNs can produce a stochastic gravitational wave background (SGWB) via cosmological first-order phase transition. In this work, we systematically investigate TeV-scale leptogenesis considering flavor effects that are crucial in low temperature regime. We also explore all possible RHN production channels which can have significant impact on the abundance of RHNs, depending on the value of $U(1)_{\rm B-L}$ gauge coupling. We demonstrate that the strong dependence of $U(1)_{\rm B-L}$ gauge sector on the baryon asymmetry as well as SGWB production can be utilized to probe a region of the model parameter space. In particular, we find that $U(1)_{\rm B-L}$ gauge boson with mass $\sim 10\,\rm TeV$ and gauge coupling $\sim 0.1$ can explain the observed baryon asymmetry and produces detectable SGWB in future detectors as well. Importantly, this region falls beyond the reach of the current collider sensitivity.

hep-ph↗

arXiv2026

Strongly electroweak phase transition with $U(1)_{L_μ-L_τ}$ gauged non-zero hypercharge triplet

This article considers three non-zero hypercharge triplets as an extension of the Standard Model Higgs doublet. Under extra $U(1)_{L_μ-L_τ}$ symmetry, the triplets are charged. We examine the stability of the electroweak vacuum at the two-loop and tree-levels. The two-loop $β$-functions are found to be capable of satisfying the vacuum stability up to the Planck scale. On the other hand, only up to $10^{12}$ GeV can the perturbative unitarity be satisfied because of the increase in the positive influence from triplet degrees of freedom. For the strongly electroweak first-order phase transition, the parameter space permitted by the Planck scale stability is examined. Because the triplet degrees of freedom contribute sufficiently to the cubic term, the model satisfies the strongly first order phase transition for the triplet bare mass parameters up to the TeV scale. For all mass ranges, it is found that this model predicts a strongly first-order phase transition until the degrees of freedom are heavy enough to separate from the thermal bath. The gravitational wave signatures are tested at the benchmark places that fulfill the strongly first-order phase transition. The measurable frequency range of the LISA and BBO experiments also turns out to contain the benchmark points permitted by Planck scale stability, strongly first-order phase transition.

hep-ph↗

arXiv2025

Phenomenology of Dirac neutrino EFTs up to dimension six

The gauge-singlet right-handed neutrinos would be essential to explain the tiny masses of active neutrinos. We consider the effective field theory of the Standard Model extended with these fields under the assumption that neutrinos are Dirac particles. In this framework, we provide a comprehensive study for the phenomenological consequences of various dimension six interactions employing various high and low energy observables. These include the neutrino mass itself, constraints from electroweak precision test and collider searches for lepton or jet plus missing energy, coherent neutrino-nucleus scattering, beta decays, as well as decays of proton, meson, tau, and top. We also study their astrophysical and cosmological implications for stellar cooling and relativistic degrees of freedom.

hep-ph↗

arXiv2025

Investigating two-zero texture in the light of gauged Type-II seesaw

Neutrino oscillation, discovered over two decades ago, confirmed that neutrinos have nonzero masses. Since then, two mass-squared differences have been measured with unprecedented precision, yet the absolute neutrino mass scale remains unknown. Additionally, the fundamental symmetry governing the neutrino mixing pattern is still undetermined. Among various theoretical possibilities, the two-zero texture in the neutrino mass matrix ($m_ν$) stands out as an attractive framework due to its reduced number of free parameters, enabling definite predictions for the unknown parameters of the PMNS matrix. In this work, we present a comprehensive analysis of the two-zero texture, focusing on its implications for the Dirac CP phase ($δ$), the Majorana phases ($ρ$, $σ$) and the effective Majorana mass ($m_{ββ}$), the latter being crucial for neutrinoless double beta decay. We find that for certain two-zero textures, $m_{ββ}$ reaches a few tens of meV, placing it within the sensitivity range of KamLAND-Zen. Furthermore, we demonstrate how a two-zero texture can naturally emerge in a well-motivated neutrino mass model, specifically the gauged Type-II seesaw mechanism, which requires multiple scalar triplets. Notably, some of the two-zero patterns cannot be realized in this framework, as more than two independent zeros appear in $m_ν$. Finally, we discuss key phenomenological consequences of the gauged Type-II seesaw model.

hep-ph↗

arXiv2025

Viability of post-inflationary freeze-in with precision cosmology

Prediction of inflationary observables from the temperature fluctuation of Cosmic Microwave Background (CMB) can play a pivotal role in predicting the reheating dynamics in the early universe. In this work, we highlight how the inflationary observables, in particular the spectral index $n_s$, can play a potential role in constraining the post-inflationary dark matter (DM) production. We demonstrate a novel way of constraining the non-thermal production of DM via UV freeze-in which is otherwise elusive in terrestrial experiments. We consider a scenario in which DM is produced from this thermal plasma via a dimension-five operator. The mutual connection between $n_s$ and relic density of DM via the reheating temperature, $T_{\rm RH}$, enables us to put constraints on the DM parameter space. For the minimal choice of the inflationary model parameters and DM mass between $1\,\rm MeV$ to $1\,\rm TeV$, we found that Planck alone can exclude the cut-off scale of the dimension-five operator $Λ\lesssim 10^{12}\,\rm GeV$ which is significantly stronger than any other existing constraints on such minimal scenario. If we impose the combined prediction form Planck and recently released data by ACT, the exclusion limit can reach up to the Planck scale for TeV-scale dark matter.

hep-ph↗

arXiv2024

Gauss-Bonnet Cosmology: large-temperature behaviour and bounds from Gravitational Waves

We provide a transparent discussion of the high temperature asymptotic behaviour of Cosmology in a dilaton-Einstein-Gauss-Bonnet (dEGB) scenario of modified gravity with vanishing scalar potential. In particular, we show that it has a clear interpretation in terms of only three attractors (stable critical points) of a set of autonomous differential equations: $w=-\frac{1}{3}$, $w=1$ and $1<w<\frac{7}{3}$, where $w\equiv p/ρ$ is the equation of state, defined as the ratio of the total pressure and the total energy density. All the possible different high-temperature evolution histories of the model are exhausted by only eight paths in the flow of the set of the autonomous differential equations. Our discussion clearly explains why five out of them are characterized by a swift transition of the system toward the attractor, while the remaining three show a more convoluted evolution, where the system follows a meta-stable equation of state at intermediate temperatures before eventually jumping to the real attractor at higher temperatures. Compared to standard Cosmology, the regions of the dEGB parameter space with $w=-\frac{1}{3}$ show a strong enhancement of the expected Gravitational Wave stochastic background produced by the primordial plasma of relativistic particles of the Standard Model. This is due to the very peculiar fact that dEGB allows to have an epoch when the energy density $ρ_{\rm rad}$ of the relativistic plasma dominates the energy of the Universe while at the same time the rate of dilution with $T$ of the total energy density is slower than what usually expected during radiation dominance. This allows to use the bound from BBN to put in dEGB a constraint $T_{\rm RH}\lesssim 10^8 - 10^9$ GeV on the reheating temperature of the Universe $T_{\rm RH}$. Such BBN bound is complementary to late-time constraints from compact binary mergers.

hep-ph↗

arXiv2023

WIMPs in Dilatonic Einstein Gauss-Bonnet Cosmology

We use the Weakly Interacting Massive Particle (WIMP) thermal decoupling scenario to probe Cosmologies in dilatonic Einstein Gauss-Bonnet (dEGB) gravity, where the Gauss-Bonnet term is non-minimally coupled to a scalar field with vanishing potential. We put constraints on the model parameters when the ensuing modified cosmological scenario drives the WIMP annihilation cross section beyond the present bounds from DM indirect detection searches. In our analysis we assumed WIMPs that annihilate to Standard Model particles through an s-wave process. For the class of solutions that comply with WIMP indirect detection bounds, we find that dEGB typically plays a mitigating role on the scalar field dynamics at high temperature, slowing down the speed of its evolution and reducing the enhancement of the Hubble constant compared to its standard value. For such solutions, we observe that the corresponding boundary conditions at high temperature correspond asymptotically to a vanishing deceleration parameter q, so that the effect of dEGB is to add an accelerating term that exactly cancels the deceleration predicted by General Relativity. The bounds from WIMP indirect detection are nicely complementary to late-time constraints from compact binary mergers. This suggest that it could be interesting to use other Early Cosmology processes to probe the dEGB scenario.

hep-ph↗

arXiv2023

Reviewing the prospect of fermion triplets as dark matter and source of baryon asymmetry in non-standard cosmology

Indirect searches of Dark Matter (DM), in conjugation with `missing track searches' at the collider seem to confine SU(2)$_L$ fermion triplet DM (FTDM) mass within a narrow range around 1 TeV. The canonical picture of the pure FTDM is in tension since it is under-abundant for the said mass range. Several preceding studies have reported that an extra species ($ϕ$), redshifts faster than the radiation ($\sim a^{-(4+n)}$ where $n>0$), leads to a faster expanding early Universe by dominating in the energy density with an enhanced Hubble parameter. This has the potential to revive the under-abundant FTDM ($\mathbb{Z}_2$ odd, lightest generation) by causing freeze-out earlier without modifying the interaction strength between DM and thermal bath. On the other hand, although the CP asymmetry produced due to the decay of $\mathbb{Z}_2$ even heavier generations of the triplet remains unaffected, its evolution is greatly affected by the non-standard cosmology. It has been observed through numerical estimations that the minimum mass of the triplet, required to produce sufficient baryon asymmetry of the Universe (BAU), can be lowered up to two orders (compared to the standard cosmology) in this fast expansion scenario. The non-standard parameters $n$ and $T_r$ (a reference temperature below which radiation dominance prevails), which simultaneously control DM abundance as well as the frozen value of BAU, are tightly constrained from the observed experimental values. We have found that $n$ is strictly bounded within the interval $0.4\lesssim n \lesssim 1.8$ where the upper bound is imposed by the BAU constraint whereas the lower bound arises to satisfy the correct DM abundance. It has been noticed that the restriction on $T_r$ is not so stringent as it can vary from sub-GeV to a few tens of GeV.

hep-ph↗

arXiv2023

Freeze-in Dark Matter via Light Dirac Neutrino Portal

We propose a scenario where dark matter (DM) can be generated non-thermally due to the presence of a light Dirac neutrino portal between the standard model (SM) and dark sector particles. The SM is minimally extended by three right handed neutrinos ($ν_R$), a Dirac fermion DM candidate ($ψ$) and a complex scalar ($ϕ$), transforming non-trivially under an unbroken $\mathbb{Z}_4$ symmetry while being singlets under the SM gauge group. While DM and $ν_R$ couplings are considered to be tiny in order to be in the non-thermal or freeze-in regime, $ϕ$ can be produced either thermally or non-thermally depending upon the strength of its Higgs portal coupling. We consider both these possibilities and find out the resulting DM abundance via freeze-in mechanism to constrain the model parameters in the light of Planck 2018 data. Since the interactions producing DM also produces relativistic $ν_R$, we check the enhanced contribution to the effective relativistic degrees of freedom $Δ{\rm N}_{\rm eff}$ in view of existing bounds as well as future sensitivities. We also check the stringent constraints on free-streaming length of such freeze-in DM from structure formation requirements. Such constraints can rule out DM mass all the way up to $\mathcal{O}(100 \, {\rm keV})$ keeping the $Δ{\rm N}_{\rm eff} \leq \mathcal{O}(10^{-3})$, out of reach from near future experiments. Possible extensions of this minimal model can lead to observable $Δ{\rm N}_{\rm eff}$ which can be probed at next generation experiments.

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arXiv2022

Improved White Dwarves Constraints on Inelastic Dark Matter and Left-Right Symmetric Models

WIMPs can be captured in compact stars such as white dwarves (WDs) leading to an increase in the star luminosity through their annihilation process. We show that when the WIMP interacts with the nuclear targets within the WD through inelastic scattering and its mass exceeds a few tens GeV the data on low-temperature large-mass WDs in the Messier 4 globular cluster can probe values of the mass splitting $δ\lesssim$ 40 MeV. Such value largely exceeds those ensuing from direct detection and from solar neutrino searches. We apply such improved constraint to the specific DM scenario of a self-conjugate bi-doublet in the Left-Right Symmetric Model (LRSM), where the standard $SU(2)_L$ group with coupling $g_L$ is extended by an additional $SU(2)_R$ with coupling $g_R$. We show that bounds from WDs significantly reduce the cosmologically viable parameter space of such scenario, in particular requiring $g_R>g_L$. For instance, for $g_R/g_L$ = 1.8 we find the two viable mass ranges 1.2 TeV $\lesssim m_χ\lesssim$ 3 TeV and 5 TeV $\lesssim m_χ\lesssim$ 10 TeV, when the charged $SU(2)_R$ gauge boson mass $M_{W_2}$ is lighter than $\simeq$ 12 TeV. We also discuss the ultraviolet completion of the LRSM model, when the latter is embedded in a Grand Unified Theory. We show that such low-energy parameter space and compatibility to proton-decay bounds require a non-trivial extension of the particle content of the minimal model. We provide a specific example where $M_{W_2}\lesssim$ 10 TeV is achieved by extending the LRSM at high energy with color triplets that are singlets under all other groups, and $g_R/g_L>$1 is obtained by introducing $SU(2)_L$ triplets with no $SU(2)_R$ counterparts, i.e. by breaking the symmetry between the multiplets of $SU(2)_L$ and $SU(2)_R$.

hep-ph↗

arXiv2022

Concealing Dirac neutrinos from cosmic microwave background

The existence of prolonged radiation domination prior to the Big Bang Nucleosynthesis (BBN), starting just after the inflationary epoch, is not yet established unanimously. If instead, the universe undergoes a non-standard cosmological phase, it will alter the Hubble expansion rate significantly and may also generate substantial entropy through non-adiabatic evolution. This leads to a thumping impact on the properties of relic species decoupled from the thermal bath before the revival of the standard radiation domination in the vicinity of the BBN. In this work, considering the Dirac nature of neutrinos, we have studied decoupling of ultra-relativistic right-handed neutrinos ($ν_R$s) in presence of two possible non-standard cosmological phases. While in both cases we have modified Hubble parameters causing faster expansions in the early universe, one of the situations predicts a non-adiabatic evolution and thereby a slower redshift of the photon temperature due to the expansion. Considering the most general form of the collision term with Fermi-Dirac distribution and Pauli blocking factors, we have solved the Boltzmann equation numerically to obtain $Δ{\rm N}_{\rm eff}$ for the three right-handed neutrinos. We have found that for a large portion of parameter space, the combined effect of early decoupling of $ν_R$ as well as the slower redshift of photon bath can easily hide the signature of right-handed neutrinos, in spite of precise measurement of $Δ{\rm N}_{\rm eff}$, at the next generation CMB experiments like CMB-S4, SPT-3G etc. This however will not be applicable for the scenarios with only fast expansion.

hep-ph↗

arXiv2022

$(g-2)_{e,\,μ}$ and strongly interacting dark matter with collider implications

The quest for new physics beyond the Standard Model is boosted by the recently observed deviation in the anomalous magnetic moments of muon and electron from their respective theoretical prediction. In the present work, we have proposed a suitable extension of the minimal $L_μ-L_τ$ model to address these two experimental results as the minimal model is unable to provide any realistic solution. In our model, a new Yukawa interaction involving first generation of leptons, a singlet vector like fermion ($χ^{\pm}$) and a scalar (either an SU(2)$_{L}$ doublet $Φ^\prime_2$ or a complex singlet $Φ^\prime_4$) provides the additional one loop contribution to $a_{e}$ only on top of the usual contribution coming from the $L_μ-L_τ$ gauge boson ($Z_{μτ}$) to both electron and muon. The judicious choice of $L_μ-L_τ$ charges to these new fields results in a strongly interacting scalar dark matter in $\mathcal{O}({\rm MeV})$ range after taking into account the bounds from relic density, unitarity and self interaction. The freeze-out dynamics of dark matter is greatly influenced by $3\rightarrow2$ scatterings while the kinetic equilibrium with the SM bath is ensured by $2\rightarrow2$ scatterings with neutrinos where $Z_{μτ}$ plays a pivotal role. The detection of dark matter is possible directly through scatterings with nuclei mediated by the SM $Z$ bosons. Moreover, our proposed model can also be tested in the upcoming $e^+e^-$ colliders by searching opposite sign di-electron and missing energy signal i.e. $e^{+} e^{-} \rightarrow χ^{+} χ^{-} \rightarrow e^{+} e^{-} \cancel{E}_T$ at the final state.

hep-ph↗

arXiv2021

Light Dirac neutrino portal dark matter with observable $Δ{N_{\rm eff}}$

We propose a Dirac neutrino portal dark matter scenario by minimally extending the particle content of the Standard Model (SM) with three right handed neutrinos ($ν_R$), a Dirac fermion dark matter candidate ($ψ$) and a complex scalar ($ϕ$), all of which are singlets under the SM gauge group. An additional $\mathbb{Z}_4$ symmetry has been introduced for the stability of dark matter candidate $ψ$ and also ensuring the Dirac nature of light neutrinos at the same time. Both the right handed neutrinos and the dark matter thermalise with the SM plasma due to a new Yukawa interaction involving $ν_R$, $ψ$ and $ϕ$ while the latter maintains thermal contact via the Higgs portal interaction. The decoupling of $ν_R$ occurs when $ϕ$ loses its kinetic equilibrium with the SM plasma and thereafter all three $\mathbb{Z}_4$ charged particles form an equilibrium among themselves with a temperature $T_{ν_R}$. The dark matter candidate $ψ$ finally freezes out within the dark sector and preserves its relic abundance. We have found that in the present scenario, some portion of low mass dark matter ($M_ψ\lesssim10$ GeV) is already excluded by the Planck 2018 data for keeping $ν_R$s in the thermal bath below a temperature of 600 MeV and thereby producing an excess contribution to $N_{\rm eff}$. The next generation experiments like CMB-S4, SPT-3G etc. will have the required sensitivities to probe the entire model parameter space of this minimal scenario, especially the low mass range of $ψ$ where direct detection experiments are still not capable enough for detection.

hep-ph↗

arXiv2021

When Freeze-out occurs due to a non-Boltzmann suppression: A study of degenerate dark sector

Exponential suppression or commonly known as the Boltzmann suppression in the number density of dark matter is the key ingredient for creating chemical imbalance prior to the usual thermal freeze-out. A degenerate/quasi-degenerate dark sector can experience a different exponential suppression in the number density analogous to the radioactive decay law leading to a delayed freeze-out mechanism of dark matter known as the co-decaying dark matter. In this work, we study the dynamics of a multicomponent dark matter from thermally decoupled degenerate dark sector in a hidden U$(1)_{X}$ extension of the Standard Model. We compute the relic density of dark matter frozen-out through the co-decaying mechanism by solving four coupled Boltzmann equations. We demonstrate how temperature $T^\prime $ of the dark sector changes due to all types of $3\rightarrow 2$ and $2\rightarrow 2$ interactions along with the eternal expansion of the Universe. We find that $3\rightarrow 2$ interactions enhance $T^\prime$ by producing energetic particles in the dark sector while the excess heat is transferred by $2\rightarrow 2$ interactions to the entire dark sector. As the direct detection is possible only through the feeble portal couplings, we investigate the neutrino and $γ$-ray signals from dark matter annihilation via one step cascade processes and compare our results with the measured fluxes of atmospheric neutrinos by Super-Kamiokande and diffuse $γ$-rays by Fermi-LAT, EGRET, INTEGRAL collaborations. We find that the present scenario easily evades all the existing bounds from atmospheric neutrino and diffuse $γ$-ray observations for degenerate dark sector. However, the constraints are significant for quasi degenerate scenario.

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arXiv2021

Spatial Reasoning from Natural Language Instructions for Robot Manipulation

Robots that can manipulate objects in unstructured environments and collaborate with humans can benefit immensely by understanding natural language. We propose a pipelined architecture of two stages to perform spatial reasoning on the text input. All the objects in the scene are first localized, and then the instruction for the robot in natural language and the localized co-ordinates are mapped to the start and end co-ordinates corresponding to the locations where the robot must pick up and place the object respectively. We show that representing the localized objects by quantizing their positions to a binary grid is preferable to representing them as a list of 2D co-ordinates. We also show that attention improves generalization and can overcome biases in the dataset. The proposed method is used to pick-and-place playing cards using a robot arm.

cs.RO↗

arXiv2021

Non-thermal production of lepton asymmetry and dark matter in minimal seesaw with right handed neutrino induced Higgs potential

Within Type-I seesaw mechanism, Higgs mass can be dynamically generated via quantum effects of the right handed neutrinos assuming the potential is nearly conformal at the Ultra-Violet. The scenario, named as the "Neutrino Option" allows RH neutrino mass scale upto $M \lesssim$ $10^7$ GeV to be consistent with light neutrino masses, mixing and Higgs mass. Therefore, it is not consistent with standard hierarchical thermal leptogenesis. Parameter space for thermal resonant leptogenesis is highly constrained in this model. We point out that non-thermal pair production of RH neutrinos from inflaton decay corresponds in general to a mild degree of resonance in the CP asymmetry parameter and allows RH mass scale to be smaller more than by an order of magnitude than the thermal strong resonance case. Within the similar parameter space of thermal leptogenesis, RH neutrinos can also be produced from inflaton decay along with a Dark Matter having mass $M_{\rm DM}\lesssim$ 320 MeV. The main constraint in the latter scenario comes from the Ly$α$ constraints on Dark Matter free streaming. We show in addition, that the Neutrino Option introduces a 'phantom window' for the RH mass scale, in which contrary to the usual scenarios, CP asymmetry parameter for leptogenesis decreases with the increase of the RH mass scale and minimally fine-tuned seesaw models naturally exhibit this `phantom window'.

hep-ph↗

arXiv2020

Fermionic dark matter via UV and IR freeze-in and its possible X-ray signature

Non-observation of any dark matter signature at various direct detection experiments over the last decade keeps indicating that immensely popular WIMP paradigm may not be the actual theory of particle dark matter. Non-thermal dark matter produced through freeze-in is an attractive proposal, naturally explaining null results by virtue of its feeble couplings with the Standard Model (SM) particles. We consider a minimal extension of the SM by two gauge singlet fields namely, a $\mathbb{Z}_2$-odd fermion $χ$ and a pseudo scalar $\tildeϕ$, where the former has interactions with the SM particles only at dimension five level and beyond. This introduces natural suppression in the interactions of $χ$ by a heavy new physics scale $Λ$ and forces $χ$ to be a non-thermal dark matter candidate. We have studied production of $χ$ in detail taking into account both ultra-violate (UV), infra-red (IR) as well as mixed UV-IR freeze-in and found that for $10^{10}{\rm GeV}\leqΛ\leq 10^{15}{\rm GeV}$, $χ$ is dominantly produced via UV and mixed UV-IR freeze-in when reheat temperature $T_{RH}\gtrsim 10^4$ GeV and below which the production is dominated by IR and mixed freeze-in. Furthermore, we have considered the cascade annihilation $χ\barχ \rightarrow \tildeϕ\tildeϕ\rightarrow 4γ$ to address the longstanding $\sim3.5$ keV X-ray line observed from various galaxies and galaxy clusters. We have found that the long-lived intermediate state $\tildeϕ$ modifies dark matter density around the galactic centre to an effective density $ρ_{eff}$ which strongly depends on the decay length of $\tildeϕ$. Finally, the allowed parameter space in $Λ-g$ plane ($g$ is the coupling between $χ\barχ$ and $\tildeϕ$) is obtained by comparing our result with the XMM Newton observed X-ray flux from the centre of Milky Way galaxy in $2σ$ range.

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arXiv2019

Beyond Node Embedding: A Direct Unsupervised Edge Representation Framework for Homogeneous Networks

Network representation learning has traditionally been used to find lower dimensional vector representations of the nodes in a network. However, there are very important edge driven mining tasks of interest to the classical network analysis community, which have mostly been unexplored in the network embedding space. For applications such as link prediction in homogeneous networks, vector representation (i.e., embedding) of an edge is derived heuristically just by using simple aggregations of the embeddings of the end vertices of the edge. Clearly, this method of deriving edge embedding is suboptimal and there is a need for a dedicated unsupervised approach for embedding edges by leveraging edge properties of the network. Towards this end, we propose a novel concept of converting a network to its weighted line graph which is ideally suited to find the embedding of edges of the original network. We further derive a novel algorithm to embed the line graph, by introducing the concept of collective homophily. To the best of our knowledge, this is the first direct unsupervised approach for edge embedding in homogeneous information networks, without relying on the node embeddings. We validate the edge embeddings on three downstream edge mining tasks. Our proposed optimization framework for edge embedding also generates a set of node embeddings, which are not just the aggregation of edges. Further experimental analysis shows the connection of our framework to the concept of node centrality.

cs.SI↗