bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative governance of for‐profit provision of public services: Investor‐owned firms versus cooperatives as internet providers
Authors: Jeong Hyoju , Kaul Aseem , Luo Jiao
Published: February 2025

Research Summary

We examine the comparative governance of for‐profit provision of public services, distinguishing between two types of for‐profit providers: investor‐owned firms (IOFs) and cooperatives. We argue that because cooperatives are owned and operated by those who benefit directly from the positive externalities generated by public services they are well suited to serving poor or high cost communities that may be underserved by IOFs, and that this will be especially true when they serve less diverse communities or needs. We test and find support for these predictions in the context of internet service provision in the United States. Our study thus offers a discriminating alignment perspective on the provision of public services, while also shedding light on the role of cooperatives in addressing societal grand challenges.

Managerial Summary

Public infrastructure and services provide two types of benefits: specific benefits to their users and general benefits to the communities they serve. Investor‐owned for‐profit firms only capture value through the payments they receive from users, however, so they may provide poorer quality service to poor or rural communities, causing such communities to be left behind. In this study, we argue that cooperatives—which are owned and controlled by members of the community themselves—represent a potential solution to this problem. Using internet service provision in the United States as a context, we show that cooperatives are more likely to enter rural and low‐income communities where existing firms are providing low quality service, and to provide higher quality service when they do so.
Controllable Detachment of Organic Ligands on Ultrathin Amorphous Nanosheets Tailors the Electron‐Aggregation for Accelerated pH‐Universal Hydrogen Reaction
Authors: Wang Wenwen , Liu Xinzheng , Feng Hui , Wan Li , Xia Chenghui , Cao Lixin , Hu Yubin , Dong Bohua
Published: February 2025

Tailoring the local environment of catalyst surface has emerged as an effective strategy to enhance the reaction kinetics involving multiple intermediates. For hydrogen evolution reactions (HER), the driving factors for hydrogen aggregation and migration which are poorly understood in depth affects the reaction kinetics especially over a wide pH range. Inspired by the selectivity of the catalyst surface microenvironment for intermediates, an interfacial electrocatalyst composed of Ru ultrafine nanocatalysts anchored onto monolayer amorphous (a‐WCoNiO) nanosheets with electron‐rich microenvironment induced by an organic oleylamine ligand is designed to realize high‐performance pH‐universal HER. This Ru/a‐WCoNiO possesses impressively low overpotentials of ‐13, ‐14, and ‐14 mV at 10 mA cm−2 in 0.5 m H2SO4, 1 m KOH and 1 m PBS, respectively, ranking among the best HER catalysts reported to date. Benefiting from the electron‐rich microenvironment, the Ru/a‐WCoNiO exhibits record‐high turnover frequency (TOF) and mass activity (MA), which is more than 47.9 times higher than that of commercial 20% Pt/C. Importantly, other precious metals are loaded on a‐WCoNiO and enhancing their mass current density for pH‐universal HER. It is believed that this developed approach of organic modifiers tailored local microenvironment has practical significance and advantages for designing other high‐performance catalysts.
Study on Grain Growth and Grain Boundary Evolution of 740H Nickel‐Based Alloys under Different Solution Treatment Conditions
Authors: Gao Saikun , Song Yaohui , Li Yugui , Lu Yibo , Zou Zhijie , Wang Jiayao , Wang Yihang , Huang Fang
Published: February 2025

This research examines the grain growth, microstructural characteristics, and grain boundary evolution of 740H nickel‐based alloy subjected to solution treatment following hot rolling. The results demonstrate that increasing the solution temperature and extending the holding time promote grain growth. A two‐stage grain growth model is developed, achieving a correlation coefficient of 0.979 and an average absolute relative error of 9.5%. The volume fraction of Σ3 grain boundaries initially increases and then decreases, peaking at 1150 °C under constant holding time. At a solution temperature of 1150 °C and a holding time of 60 min, the proportion of special grain boundaries in the sample reaches a maximum of 61.1%, with Σ3 grain boundaries comprising the majority at 59.8%. Their morphology progressively evolves into long, straight double Σ3 grain boundaries, and the distribution of grain boundary clusters becomes increasingly concentrated. Grain boundary engineering analysis reveals that during grain growth, twins gradually form and proliferate, dislocation recovery in the alloy is enhanced, and residual stress is progressively reduced. Under the conditions of 1150 °C solution temperature and 60 min holding time, grain boundary regulation performance is optimized, establishing this as the most effective heat treatment process.
Strong Tough Hydrogel with Regional Programmable Mechanical Properties via Universal Physical Directional Anneal‐Casting Strategy for Bioengineering
Authors: Zhu He , Dai Ziyi , Yang Yican , Fan Xiaoli , Wang Cheng , Zhang Yang , Cai Rong , Qian Kai
Published: February 2025

Engineering tissue‐like hydrogels with tailored mechanical properties and matching water contents is essential for biomimetic organ platforms in both ex vivo and in vivo biomedical applications. Achieving this goal is particularly challenging due to the need for a green, straightforward, and universally applicable approach to mimic various tissues with specific hydrogels. Herein, a universal physical one‐step directional anneal‐casting strategy for anisotropic water evaporation is presented to produce hierarchical anisotropic poly(vinyl alcohol) hydrogel with tunable Young's modulus (≈0.13–77.2 MPa) in a wide range. As a typical example, the ultimate stress, toughness, fracture energy, and fatigue threshold of strong tough poly(vinyl alcohol) hydrogels can be up to 31.8 MPa, 45.7 MJ m−3, 568.6 kJ m−2, and 407.8 J m−2 at ≈208% strain with controllable water content (≈20–80%) without compromising their toughness. Integral to our approach is the capability for localized control of mechanical properties within the same hydrogel unit, allowing for distinct functional characteristics in different regions of the hydrogel. Furthermore, the versatility of our strategy extends to various other hydrogel systems, such as polyacrylamide and alginate, broadening its applicability in the fields of bioelectronics and biomedical engineering, including the development of physiological signal acquisition devices and artificial implantable electronic ligaments.
A State‐of‐the‐Art Review on Effectiveness of Geopolymer Technology Toward Dye Degradation, Heavy Metal Encapsulation and Its Future Prospects on Environmental Remediation
Authors: SV Siva Shankari , M Sivasakthi
Published: February 2025

Geopolymers are an innovative class of environmentally friendly materials gaining significant attention in construction, materials science, and sustainable technology. As alternatives to traditional cement‐based materials, geopolymers exhibit unique mechanical properties suitable for various construction applications, including use as construction materials, coating materials, and high‐temperature‐resistant materials. Notably, geopolymers can effectively adsorb heavy metals, dyes, and radioactive pollutants, offering substantial environmental benefits. This review paper explores the process and mechanism of geopolymerization, as well as the application of geopolymers in the treatment of contaminants. It details how aluminosilicate precursors contribute to the photocatalytic degradation of dyes, examining the role of different raw material sources, types of activators or additives used, and preparation methods. This paper highlights the effectiveness of geopolymers in dye degradation, providing insights into the underlying mechanisms. Additionally, the review delves into the interaction of geopolymers with heavy metals through mechanisms such as chemisorption, complexation, adsorption, ion exchange, intraparticle diffusion, and the solidification of heavy metals within the geopolymer matrix. This comprehensive analysis of existing research aids researchers in understanding the capabilities and limitations of geopolymer materials in environmental remediation. Beyond waste reduction, the review addresses the broader environmental impact of geopolymers, particularly their potential for reducing the carbon footprint compared to traditional cement. This aspect is crucial for evaluating the overall sustainability of geopolymers. Furthermore, the paper emphasizes the importance of life cycle durability assessments (LCA) to evaluate the ecological footprint of this eco‐friendly concrete throughout its lifetime, from raw material to end‐of‐life disposal. LCA provides a complete perspective on the sustainability of geopolymers, guiding future research and applications in sustainable construction. By synthesizing current research on geopolymers, this review paper serves as a valuable resource for researchers in geopolymer technology, offering insights into future research directions and potential applications.
Biomimetic Nanomaterials Based on Peptide In Situ Self‐Assembly for Immunotherapy Applications
Authors: Wen Zhuan , Song Zhang‐Zhi , Cai Ming‐Ze , Zhang Ni‐Yuan , Li Hao‐Ze , Yang Yang , Wang Qian‐Ting , Ghafoor Muhammad Hamza , An Hong‐Wei , Wang Hao
Published: February 2025

Cancer remains the leading cause of patient death worldwide and its incidence continues to rise. Immunotherapy is rapidly developing due to its significant differences in the mechanism of action from conventional radiotherapy and targeted antitumor drugs. In the past decades, many biomaterials have been designed and prepared to construct therapeutic platforms that modulate the immune system against cancer. Immunotherapeutic platforms utilizing biomaterials can markedly enhance therapeutic efficacy by optimizing the delivery of therapeutic agents, minimizing drug loss during circulation, and amplifying immunomodulatory effects. The intricate physiological barriers of tumors, coupled with adverse immune environments such as inadequate infiltration, off‐target effects, and immunosuppression, have emerged as significant obstacles impeding the effectiveness of oncology drug therapy. However, most of the current studies are devoted to the development of complex immunomodulators that exert immunomodulatory functions by loading drugs or adjuvants, ignoring the complex physiological barriers and adverse immune environments of tumors. Compared with conventional biomaterials, biomimetic nanomaterials based on peptide in situ self‐assembly with excellent functional characteristics of biocompatibility, biodegradability, and bioactivity have emerged as a novel and effective tool for cancer immunotherapy. This article presents a comprehensive review of the latest research findings on biomimetic nanomaterials based on peptide in situ self‐assembly in tumor immunotherapy. Initially, we categorize the structural types of biomimetic peptide nanomaterials and elucidate their intrinsic driving forces. Subsequently, we delve into the in situ self‐assembly strategies of these peptide biomimetic nanomaterials, highlighting their advantages in immunotherapy. Furthermore, we detail the applications of these biomimetic nanomaterials in antigen presentation and modulation of the immune microenvironment. In conclusion, we encapsulate the challenges and prospective developments of biomimetic nanomaterials based on peptide in situ self‐assembly for clinical translation in immunotherapy.
Considerations Concerning State Ratification of the BBNJ Agreement
Authors: Ardron Jeff A. , Kachelriess Daniel , Lyal Christopher H. C. , Nwapi Chilenye , Rabone Muriel , Sirakaya Aysegul , Swaddling Alison
Published: February 2025

This paper presents procedural, policy, and legal considerations that states may encounter before and after ratifying the BBNJ Agreement, with a focus on its marine genetic resources (MGR) provisions. It briefly examines the behaviours of parties to the other two previously ratified implementing agreements to the United Nations Convention on the Law of the Sea, as well as some ratification lessons learnt from other relevant treaties. The other three ‘pillars’ of the BBNJ Agreement sit on well-established foundations of national and international law. However, as discussed here, the legal foundation of the fourth pillar, MGR, is less well established nationally or internationally, and much remains to be determined. Therein, the BBNJ Agreement represents a significant advancement of international law. However, the reality is that most parties will not adopt all the necessary new legislation prior to their ratification, nor can they, because many of the MGR provisions are as yet still unclear. States are therefore likely to choose a progressive approach, ratifying the Agreement to signal commitment while gradually developing the legal framework necessary for full compliance, as well as policies to guide its implementation.
Marine Genetic Resources Beyond National Jurisdiction: The Expansive Scope of the BBNJ Agreement
Authors: Humphries Fran
Published: February 2025

This chapter interprets the scope and key definitions in Part II Marine Genetic Resource governance of the Biodiversity Beyond National Jurisdiction (BBNJ) Agreement. The purpose of this chapter is to: (a) aid practitioners and policy makers’ understanding of the rationale underlying the treaty obligations and key gaps in interpretation; (b) outline how scope and definitions shape the treaty framework and institutional arrangements; and (c) provide practical considerations for how scope and definitions might be implemented in practice by Parties. Through a textual analysis of the treaty and its evolution during preparatory and intergovernmental committee meetings, it critically analyzes scope in three dimensions: jurisdiction (geography, sovereignty and relationships with other instruments, frameworks and bodies); subject matter (physical materials, sequence information, traditional knowledge, activities and exclusions); and temporal scope (including retrospectivity). The chapter analyzes the principles of ‘without prejudice’, ‘non-appropriation’, ‘due diligence’ and ‘not undermining’ in the treaty context. It concludes that the BBNJ Agreement has an expansive scope requiring clarification and calibration by treaty bodies for a common approach to implementation by Parties.
Traditional Knowledge Associated with Marine Genetic Resources in Areas Beyond National Jurisdiction
Authors: Pena-Neira Sergio , Coelho Luciana Fernandes
Published: February 2025

This chapter analyzes and interprets the current international legal discussions and regulations concerning traditional knowledge in the Agreement Under the United Nations Convention on the Law of the Sea on the Conservation and Sustainable Use of Marine Biological Diversity of Areas Beyond National Jurisdiction. The analysis focuses on how the agreement addresses traditional knowledge and those producing this kind of knowledge: indigenous peoples and local communities (distinguishing between them) exploring the state of the art in recognizing traditional knowledge across various areas of international law. Additionally, the chapter aims to provide an effective application of these rules by examining the relationship between the agreement and other treaties ruling traditional knowledge, elements of traditional knowledge, and the interpretation and implementation of Article 13 of the Agreement, which serves as the principal source of regulation. A case study is presented to illustrate this implementation. The interpretation is guided by the Vienna Convention on the Law of Treaties and other relevant international agreements concerning genetic resources.
Understanding Employee Involvement and Participation in Brunei Darussalam: A Public Sector Organisation Undergoing Change
Authors: Sumardi Wardah Azimah
Published: February 2025

Most studies on employee involvement and participation, particularly those in Western Europe, North America, Britain and Japan, are conceived within a landscape that opens up the mechanism of giving employees a voice. By contrast, researchers have called for studies to look at developments in employee involvement and participation in limited or non-trade union settings in order to determine the route they follow and their implications. Addressing this call, this chapter presents an account of the development of employee involvement and participation in a public sector organisation in Brunei Darussalam, framed against the backdrop of organisational change—particularly in a system that offers minimal outlet for employees’ voice in its governance process, borne from an assertive government presence. Key findings reveal that employee involvement and participation in such a context could be interpreted as part of an efficiency control programme, which takes the form of managerial and operational-oriented processes and structures such as autonomous meetings and teamwork. Brunei is generally ruled by a strong sense of conformity and consensus in which human resource management practice in the public sector is shaped by general orders and state circulars that date to the early 1960s, covering key elements such as appointments, promotions, benefit entitlements, work etiquette and discipline. This practice seems to paint a picture of a system based on ‘unity’, where everyone allegedly strives jointly towards a common objective, following the leadership of an appointed manager or supervisor. Given such unitarist employment relations, employee involvement and participation in Brunei are primarily focused on fostering ideas to help improve organisational effectiveness rather than being about grievance procedures.
Brunei Darussalam’s Economic Diversification Drive: An Assessment of the Socioeconomic and Geopolitical Issues and Challenges. Overcoming Path Dependence?
Authors: Hashim Hafiizh , Druce Stephen C. , Julay Abdul Hai
Published: February 2025

This chapter uses an institutionalist approach to present an assessment of the key issues Brunei Darussalam currently faces in relation to its pressing need for economic diversification. Given that institutional arrangements can hinder or enhance economic growth, the institutional approach has been central in explaining policies associated with economic growth and development in various countries. The approach also offers a wealth of literature that can be used to explain Brunei’s difficulties in reducing its long-standing dependency on hydrocarbons, the extent to which institutions play a role in its economic development and in understanding the complexity of Brunei’s political economy. The discussion does not claim to provide a solution to Brunei’s economic diversification problem but rather offers some contextualisation that can be of benefit to scholars and policymakers in understanding its symptoms. The chapter also addresses current geopolitical issues and the increasing interconnectivity between Brunei’s international relations and economic diversification as it attempts to attract more foreign direct investment.
Meeting the Skills Demands of Employers in Brunei Darussalam: Where Do the Youth Stand?
Authors: Hisa Adilah , Naqshbandi M. Muzamil , Mohiddin Fadzliwati
Published: February 2025

To better understand how young people are progressing in meeting changing workplace demands, it is salient to probe the sentiments of employers who hold a fundamental role in youth employability. This chapter presents the main ingredients for enhancing employability from the perspective of employers in Brunei Darussalam. It specifically explores the fundamental employability skills needed by youth in the marketplace and their current potential in executing such skills from the employers’ standpoint. The discussion highlights key opportunities and provides recommendations to the relevant stakeholders about potential avenues to pursue in order to alleviate unemployment in Brunei. The findings enrich the extant literature by delivering empirical evidence on youth employability skills, a topic of significant interest and value to young job seekers. At the same time, the chapter provides insights for educators and practitioners to implement fruitful initiatives for managing unemployment in Brunei.
Radiative origin of fermion mass hierarchy in left-right symmetric theory
Authors: Jana Sudip , Klett Sophie , Lindner Manfred , Mohapatra Rabindra N.
Published: February 2025

Abstract

Despite the remarkable success of the Standard Model, the hierarchy and patterns of fermion masses and mixings remain a profound mystery. To address this, we propose a model employing the rank mechanism, where the originally massless quarks and leptons sequentially get masses. The third generation masses originate from the seesaw mechanism at the tree-level, while those of the second and first generations emerge from one-loop and two-loop radiative corrections, respectively, with a progressive increase in the rank of the mass matrix. This approach does not require new discrete or global symmetries. Unlike other theories of this type that require the introduction of additional scalars, we employ the double seesaw mechanism within a left-right symmetric framework, which allows us to realize this scenario solely through gauge interactions.
Radial canonical AdS3 gravity and $$ T\overline{T} $$
Authors: Blacker Matthew J. , Callebaut Nele , Hergueta Blanca , Ning Sirui
Published: February 2025

Abstract

We employ an ADM deparametrization strategy to discuss the radial canonical formalism of asymptotically AdS3 gravity. It leads to the identification of a radial ‘time’ before quantization, which is the volume time, canonically conjugate to York time. Holographically, this allows to interpret the semi-classical path integral of

$$ T\overline{T} $$

T

T
¯

theory as a Schrödinger wavefunctional satisfying a Schrödinger evolution equation in volume time, and the

$$ T\overline{T} $$

T

T
¯

operator expectation value in terms of the Hamiltonian that generates volume time translations — both consistent with cut-off holography. We make use of the canonical perspective to construct the rotating BTZ solution from the Hamilton-Jacobi equation, with a finite cut-off energy spectrum that has a known holographic

$$ T\overline{T} $$

T

T
¯

interpretation, as well as semi-classical Wheeler-DeWitt states for that solution.
Fully charmed tetraquark production at the LHC experiments
Authors: Belov Ilia , Giachino Alessandro , Santopinto Elena
Published: February 2025

Abstract

We develop the formalism for production of a fully heavy tetraquark and apply it to the calculation of pp → T
4c
+ X cross-sections. We demonstrate that the production cross-section of a fully heavy tetraquark, even if it is a diquark-antidiquark cluster, can be obtained in the meson-like basis, for which the spin-color projection technique is well established. Prompted by the recent LHCb, ATLAS and CMS data, we perform a pQCD calculation of

$$ \mathcal{O} $$

O

(

$$ {\alpha}_s^5 $$

α
s
5

) short-distance factors in the dominant channel of gluon fusion, and match these to the four-body T
4c
wave functions in order to obtain the unpolarized T
4c
(0++
, 1+−

, 2++) cross-sections. The novelty in comparison with the recently published article [1] lies in the fact that we predict the absolute values as well as the dσ/dp

T
spectra in the kinematic ranges accessible at the ongoing LHC experiments. From the comparison with the signal yield at LHCb we derive the constraints on the Φ · Br(J/ψ J/ψ) (reduced wave function times branching) product for the T
4c
candidates for X(6900) and observe that X(6900) is compatible with a 2++(2S) state.
FPF@FCC: neutrino, QCD, and BSM physics opportunities with far-forward experiments at a 100 TeV Proton Collider
Authors: Mammen Abraham Roshan , Adhikary Jyotismita , Feng Jonathan L. , Fieg Max , Kling Felix , Li Jinmian , Pei Junle , Rabemananjara Tanjona R. , Rojo Juan , Trojanowski Sebastian
Published: February 2025

Abstract

Proton-proton collisions at energy-frontier facilities produce an intense flux of high-energy light particles, including neutrinos, in the forward direction. At the LHC, these particles are currently being studied with the far-forward experiments FASER/FASERν and SND@LHC, while new dedicated experiments have been proposed in the context of a Forward Physics Facility (FPF) operating at the HL-LHC. Here we present a first quantitative exploration of the reach for neutrino, QCD, and BSM physics of far-forward experiments integrated within the proposed Future Circular Collider (FCC) project as part of its proton-proton collision program (FCC-hh) at

$$ \sqrt{s} $$

s

≃ 100 TeV. We find that 109 electron/muon neutrinos and 107 tau neutrinos could be detected, an increase of several orders of magnitude compared to (HL-)LHC yields. We study the impact of neutrino DIS measurements at the FPF@FCC to constrain the unpolarised and spin partonic structure of the nucleon and assess their sensitivity to nuclear dynamics down to x ∼ 10
−9 with neutrinos produced in proton-lead collisions. We demonstrate that the FPF@FCC could measure the neutrino charge radius for ν

e
and ν

μ
and reach down to five times the SM value for ν

τ
. We fingerprint the BSM sensitivity of the FPF@FCC for a variety of models, including dark Higgs bosons, relaxion-type scenarios, quirks, and millicharged particles, finding that these experiments would be able to discover LLPs with masses as large as 50 GeV and couplings as small as 10
−8, and quirks with masses up to 10 TeV. Our study highlights the remarkable opportunities made possible by integrating far-forward experiments into the FCC project, and it provides new motivation for the FPF at the HL-LHC as an essential precedent to optimize the forward physics experiments that will enable the FCC to achieve its full physics potential.
AdS amplitudes as CFT correlators
Authors: Bañados Máximo , Bianchi Ernesto , Muñoz Iván , Skenderis Kostas
Published: February 2025

Abstract

We show that AdS amplitudes are CFT correlators to all orders in the loop expansion by showing that they obey the conformal Ward identities. In particular, we provide explicit formulas for the constants and functions of cross-ratios that determine the CFT correlators in terms of bulk data.
Ramp from replica trick
Authors: Cao Xuchen , Faulkner Thomas
Published: February 2025

Abstract

We compute the spectral form factor of the modular Hamiltonian K = −ln ρ

A
associated to the reduced density matrix of a Haar random state. A ramp is demonstrated and we find an analytic expression for its slope. Our method involves an application of the replica trick, where we first calculate the correlator

$$ \left\langle \textrm{tr}{\rho}_A^n tr{\rho}_A^m\right\rangle $$

tr

ρ
A
n

tr

ρ
A
m

at large bond dimension and then analytically continue the indices n, m from integers to arbitrary complex numbers. We use steepest descent methods at large modular times to extract the ramp. The large bond dimension limit of the replicated partition function is dominated by a sum over annular non-crossing permutations. We explored the similarity between our results and calculations of the spectral form factor in low dimensional gravitational theories where the ramp is determined by the double trumpet geometry. We find there is an underlying resemblance in the two calculations, when we interpret the annular non-crossing permutations as representing a discretized version of the double trumpet. Similar results are found for an equilibrated pure state in place of the Haar random state.
Classical eikonal from Magnus expansion
Authors: Kim Joon-Hwi , Kim Jung-Wook , Kim Sungsoo , Lee Sangmin
Published: February 2025

Abstract

In a classical scattering problem, the classical eikonal is defined as the generator of the canonical transformation that maps in-states to out-states. It can be regarded as the classical limit of the log of the quantum S-matrix. In a classical analog of the Born approximation in quantum mechanics, the classical eikonal admits an expansion in oriented tree graphs, where oriented edges denote retarded/advanced worldline propagators. The Magnus expansion, which takes the log of a time-ordered exponential integral, offers an efficient method to compute the coefficients of the tree graphs to all orders. We exploit a Hopf algebra structure behind the Magnus expansion to develop a fast algorithm which can compute the tree coefficients up to the 12th order (over half a million trees) in less than an hour. In a relativistic setting, our methods can be applied to the post-Minkowskian (PM) expansion for gravitational binaries in the worldline formalism. We demonstrate the methods by computing the 3PM eikonal and find agreement with previous results based on amplitude methods. Importantly, the Magnus expansion yields a finite eikonal, while the naïve eikonal based on the time-symmetric propagator is infrared-divergent from 3PM on.
The Feyn-structure of Yangian symmetry
Authors: Loebbert Florian , Mathur Harshad
Published: February 2025

Abstract

Yangian-type differential operators are shown to constrain Feynman integrals beyond the restriction to integrable graphs. In particular, we prove that all position-space Feynman diagrams at tree level feature a Yangian level-one momentum symmetry as long as their external coordinates are distinct. This symmetry is traced back to a set of more elementary bilocal operators, which annihilate the integrals. In dual momentum space, the considered Feynman graphs represent multi-loop integrals without ‘loops of loops’, generalizing for instance the family of so-called train track or train track network diagrams. The extension of these results to integrals with massive propagators on the boundary of the Feynman graph is established. When specializing to the dual conformal case, where propagator powers sum up to the spacetime dimension at each position-space vertex, the symmetry extends to the full dual conformal Yangian. Hence, our findings represent a generalization of the statements on the Yangian symmetry of Feynman integrals beyond integrability and reveal its origin lying in a set of more elementary bilocal annihilators. Previous applications of the Yangian suggest to employ the resulting differential equations for bootstrapping multi-loop integrals beyond the dual conformal case. The considered bilocal constraints on Feynman integrals resemble the definition of conformal partial waves via Casimir operators, but are based on a different algebraic structure.
Bound states of massive complex ghosts in superrenormalizable quantum gravity theories
Authors: Asorey M. , Krein G. , Pardina M. , Shapiro I.
Published: February 2025

Abstract

One of the remarkable differences between renormalizable quantum gravity with four-derivative action and its superrenormalizable polynomial generalizations is that the latter admit a more sophisticated particle mass spectrum. Already in the simplest superrenormalizable case, the theory has a six-derivative Lagrangian, admitting either a real or complex spectrum of masses. In the case of a real spectrum, there are the graviton, massive unphysical ghosts, and normal particles with masses exceeding the ones of the ghosts. It is also possible to have pairs of complex conjugate massive ghost-like particles. We show that in both cases, these theories do not admit a Källén-Lehmann representation and do not satisfy the positivity criterium of consistency in terms of the fields associated to those particles. In the main part of the work, using a relatively simple Euclidean scalar toy model, we show that the theory with complex spectrum forms bound states confining unphysical massive excitations into a normal composite particle. Finally, we discuss the cosmological implications of such a ghost confinement.
Grand unification at the cosmological collider with chemical potential
Authors: Bodas Arushi , Broadberry Edward , Sundrum Raman
Published: February 2025

Abstract

We introduce a tree-level chemical potential mechanism for spin-1 particles within cosmological collider physics, allowing them to be detected in primordial non-Gaussianities for masses above the inflationary Hubble scale. We apply this mechanism to orbifold grand unification and the massive unification partners of the standard model gauge bosons. Our mechanism requires at least a pair of massive vector fields which are singlets of the standard model, a condition which is satisfied in the classic “trinification” scenario. Assuming that the gauge hierarchy problem is solved by supersymmetry, gauge coupling running points to unification partners at ~ 1015 GeV. We show that, within high-scale inflation, chemical potential enhancement can lead to observably strong signals for trinification partners in future cosmological surveys.
Extremal jumps of circuit complexity of unitary evolutions generated by random Hamiltonians
Authors: Kotowski Marcin , Oszmaniec Michał , Horodecki Michał
Published: February 2025

Abstract

We investigate circuit complexity of unitaries generated by time evolution of randomly chosen strongly interacting Hamiltonians in finite dimensional Hilbert spaces. Specifically, we focus on two ensembles of random generators — the so called Gaussian Unitary Ensemble (GUE) and the ensemble of diagonal Gaussian matrices conjugated by Haar random unitary transformations. In both scenarios we prove that the complexity of exp(–itH) exhibits the following behaviour — with high probability it reaches the maximal allowed value on the same time scale as needed to escape the neighborhood of the identity consisting of unitaries with trivial (zero) complexity. We furthermore observe similar behaviour for quantum states originating from time evolutions generated by above ensembles and for diagonal unitaries generated from the ensemble of diagonal Gaussian Hamiltonians. To establish these results we rely heavily on structural properties of the above ensembles (such as unitary invariance) and concentration of measure techniques. This gives us a much finer control over the time evolution of complexity compared to techniques previously employed in this context: high-degree moments and frame potentials.
Dynamic critical behavior of the chiral phase transition from the real-time functional renormalization group
Authors: Roth Johannes V. , Ye Yunxin , Schlichting Sören , von Smekal Lorenz
Published: February 2025

Abstract

The collective dynamics around the second-order O(4) chiral phase transition in QCD with two massless quark flavors can be understood by appealing to universality. We present a novel formulation of the real-time functional renormalization group (FRG) that describes the stochastic hydrodynamic equations of motion for systems in the same dynamic universality class, which corresponds to Model G in the Halperin-Hohenberg classification. Our approach preserves all relevant symmetries of such systems with reversible mode couplings, which establishes the real-time FRG as a valuable tool complementary to classical-statistical simulations. As a first application we show that our approach is consistent with dynamic scaling relations and reproduces the non-trivial value z = d/2 for the dynamic critical exponent in d spatial dimensions. Moreover, we extract a novel dynamic scaling function that describes the universal momentum and temperature dependence of the diffusion coefficient of iso-(axial-)vector charge densities in the symmetric phase.
Non-diagonal DVCS and transition GPDs: a unified framework for spinless hadron case γ*π → γππ
Authors: Son Sangyeong , Semenov-Tian-Shansky Kirill M.
Published: February 2025

Abstract

Hadron-to-two-hadron transition generalized parton distributions (GPDs) extend the concept of hadron-to-resonance transition GPDs and provide a unified description of non-diagonal hard exclusive reactions in the generalized Bjorken limit. We present the formalism for the case of spinless hadrons addressing the non-diagonal deeply virtual Compton scattering γ

*

π → γππ in terms of π → ππ transition GPDs, which generalize GPDs for π → f
0, ρ, f
2, ⋯ transitions. We work out the basic properties of π → ππ transition GPDs and establish the soft pion theorems at the 2π production threshold. We construct the partial wave expansion of π → ππ transition GPDs in the two-pion decay angles and employ the dispersive approach to constrain π → ππ transition GPDs in terms of ππ-scattering phases with help of the Omnès representation. We estimate the e

−

π
+ → e

−

γπ
+
π
0 cross section in the kinematics of the JLab@12 GeV incorporating the isolated ρ(770) resonance state and work out the angular distributions of the cross section, specifying the observables sensitive to the polarization states of the produced ρ(770) resonance.
Massive spectrum in F-theory and the distance conjecture
Authors: Chen Keren , Lou Qinjian , Wang Yi-Nan
Published: February 2025

Abstract

We investigate the massive states in F-theory compactification models, including BPS string junctions stretching between parallel 7-branes and KK modes. We obtain analytical results when there are two colliding bunches of 7-branes with a locally constant axiodilaton profile. In particular, in 8D F-theory setups when the 7-branes collide into a codimension-one (4, 6, 12) singularity, we found an infinite light tower of BPS string junctions, which should match the light KK tower in the dual heterotic description. To exactly match with the results in the distance conjecture, we propose that the definition of 8D Planck mass should receive a large correction. We have also computed parts of KK modes in 8D F-theory in a simplified setup, as well as the BPS string junction spectrum in specific setups of 6D and 4D F-theory.
Bootstrapping line defects in AdS3/CFT2
Authors: Bliard Gabriel , Correa Diego H. , Lagares Martín , Landea Ignacio Salazar
Published: February 2025

Abstract

We study correlators of insertions along 1/2 BPS line defects in the holographic dual to type IIB string theory in AdS
3 × S
3 × T
4 with mixed Ramond-Ramond and Neveu Schwarz-Neveu Schwarz three-form flux. These defects break the symmetries of the bulk CFT2 as PSU(1, 1|2)2 × SO(4) → PSU(1, 1|2) × SU(2), defining displacement and tilt supermultiplets. We focus on the two-, three- and four-point functions of these supermultiplets, which we compute using analytic conformal bootstrap up to next-to-leading order in their strong-coupling expansion. We obtain a bootstrap result that only depends on two OPE coefficients. We perform a Witten diagram check of the bootstrap result, obtaining an holographic interpretation of the two OPE coefficients that are not constrained by the bootstrap procedure.
Dark-matter induced neutron-antineutron oscillations
Authors: Brugeat Théo , Smith Christopher
Published: February 2025

Abstract

If dark matter carries a baryon number of two, neutron-antineutron oscillations could require its presence to manifest themselves. If it is in addition very light, in the micro-eV range or up to a few orders of magnitude below, these oscillations could even exhibit a Rabi resonance. Though the magnetic tuning required to convert a macroscopic number of neutrons into antineutrons is not realistic, sizeable enhancements remain possible. Building on this observation, axionic realizations for this scenario are systematically analyzed. For true QCD axion models, we find that the Goldstone boson nature of the axion imposes the presence of axionless

$$ n-\overline{n} $$

n
−

n
¯

mixing effects, either in vacuum or in decays, which are sufficiently constrained experimentally to leave no room for axion-induced oscillations. Thus, a generic scalar or axion-like dark matter background would have to exist to induce resonant

$$ n-\overline{n} $$

n
−

n
¯

oscillations. Yet, if Nature has taken that path to relate dark matter and baryon number violation, the experimental signature would be striking and certainly worth pursuing.
Metallic transports from accelerating black holes
Authors: Roychowdhury Dibakar
Published: February 2025

Abstract

We probe four dimensional accelerating black holes with D-brane and build up the notion of metallic holography for spacetime with negative cosmological constant. We explore various thermodynamic entities associated with the boundary QFT at low temperatures and finite chemical potential. The DC conductivity in the boundary QFT is enhanced due to the effects of black hole acceleration in the bulk counterpart. We further compute resistivity in different temperature regime, which reveals a new quantum liquid phase with dynamic critical exponent z = 3.
Swampland bounds on magnetized extra dimensions
Authors: Hamada Yuta , Takeuchi Maki
Published: February 2025

Abstract

We consider a six-dimensional U(1) gauge theory compactified on two-dimensional manifolds. The number of chiral fermions is determined by the flux quantization number on the two-dimensional compact manifolds. Using the Swampland Conjectures, we find constraints among the parameters of the theory: the flux quantization number, the compactification scale, and the string scale. Specifically, the Weak Gravity Conjecture and the Trans-Planckian Censorship Conjecture give non-trivial bounds.
Sterile sector impacting the correlations and degeneracies among mixing parameters at the Deep Underground Neutrino Experiment
Authors: Parveen Sabila , Masud Mehedi , Bishai Mary , Mehta Poonam
Published: February 2025

Abstract

We investigate the physics potential of the upcoming Deep Underground Neutrino Experiment (DUNE) in probing active-sterile mixing. We present analytic expressions for relevant oscillation probabilities for three active and one sterile neutrino of eV-scale mass and highlight essential parameters impacting the oscillation signals at DUNE. We then explore the space of sterile parameters as well as study their correlations among themselves and with parameters appearing in the standard framework (δ
13 and θ
23). We perform a combined fit for the near and far detector at DUNE using GLoBES. We consider alternative beam tune (low energy and medium energy) and runtime combinations for constraining the sterile parameter space. We show that charged current and neutral current interactions over the near and far detector at DUNE allow for an improved sensitivity for a wide range of sterile neutrino mass splittings.
Gauging generalised symmetries in linear gravity
Authors: Hull Chris , Hutt Maxwell L. , Lindström Ulf
Published: February 2025

Abstract

The theory of a free spin-2 field on Minkowski spacetime has 1-form and (d − 3)-form symmetries associated with conserved currents formed by contractions of the linearised Riemann tensor with conformal Killing-Yano 2-forms. We show that a subset of these can be interpreted as Noether currents for specific shift symmetries of the graviton that involve a Killing vector and a closed 1-form parameter. We give a systematic method to gauge these 1-form symmetries by coupling the currents to background gauge fields and introducing a particular set of counter-terms involving the background fields. The simultaneous gauging of certain pairs of 1-form and (d − 3)-form symmetries is obstructed by the presence of mixed ’t Hooft anomalies. The anomalous pairs of symmetries are those which are related by gravitational duality. The implications of these anomalies are discussed.
Defect groups of class $$ \mathcal{S} $$ theories from the Coulomb branch
Authors: Gårding Elias Riedel
Published: February 2025

Abstract

We study the global forms of class

$$ \mathcal{S}\left[{A}_{N-1}\right] $$

S

A

N
−
1

4d

$$ \mathcal{N} $$

N

= 2 theories by deriving their defect groups (charges of line operators up to screening by local operators) from Coulomb branch data. Specifically, we employ an explicit construction of the BPS quiver for the case of full regular punctures to show that the defect group is (ℤ

N
)2g
, where g is the genus of the associated Riemann surface. This determines a sector of surface operators in the 5d symmetry TFT. We show how these can also be identified from dimensional reduction of M-theory. We discuss connections to the theory of cluster algebras.
Phenomenology of electroweak portal dark showers: high energy direct probes and low energy complementarity
Authors: Cheng Hsin-Chia , Jiang Xu-Hui , Li Lingfeng
Published: February 2025

Abstract

We investigate the phenomenology of a dark QCD sector interacting with the Standard Model (SM) via the electroweak (EW) portals. The portal interactions allow SM bosons, such as Z and h, or additional bosons that mix with them, to decay into dark quarks, producing dark showers. The light dark mesons are expected to be long-lived particles (LLPs), as their decays back to the SM states through the EW-portal interactions typically have macroscopic decay lengths. We focus on dark shower events initiated by various bosons at the Large Hadron Collider (LHC). The most prominent signal is the displaced decay of GeV-scale dark pions as LLPs. Current limits on dark shower signals at LHC detectors are recast from public data to provide simplified limits insensitive to UV physics details. Future limits in the high-luminosity phase and proposed auxiliary detectors are also projected. Additionally, we study the flavor-changing neutral current (FCNC) B decays into dark pions, obtaining both current and projected constraints at the LHC and other facilities. These constraints can be combined for specific models, which are illustrated in two EW-portal benchmarks: one with the heavy doublet fermion mediation and another with the Z′ mediator including a mass mixing. The collider reach shows significant potential to probe the parameter space unconstrained by EW precision tests, highlighting the necessity of dedicated LLP search strategies and facilities.
Backreacted Coulomb energy in the Skyrme model
Authors: Gudnason Sven Bjarke , Speight James Martin
Published: February 2025

Abstract

The Skyrme model is extended with the Maxwell action and a source term for the gauge field. We consider the specialized case of vanishing isospin states, such that only an electric potential is turned on and study the backreaction onto the Skyrme fields. In particular, we study Skyrmions with baryon numbers B = 4, 8, 12, 16 and 40. We find, in agreement with physical expectations, that the Coulomb backreaction is most pronounced for large Skyrmions and find furthermore that the dynamics of the theory is more sensitive to the backreaction than the ground states (global minimizers of the energy). Calibrating the model to Carbon-12, we find excellent agreement of the masses of the studied Skyrmions — within 1.86% of experimental data. The Coulomb energies are slightly larger than phenomenological fits suggest, but only by about 3 – 22%, whereas the radii are within 15% errors, with the largest errors on the smallest baryon number (B = 4) and the smallest errors on the large baryon numbers.
(2, 2p + 1) minimal string and intersection theory I
Authors: Artemev A. , Chaban I.
Published: February 2025

Abstract

In view of the recent progress in studying matrix model-2D gravity duality, we reexamine some features of (2, 2p + 1) minimal string. After reviewing both sides of the proposed correspondence in this case, a previously unnoted identification between correlation numbers of tachyon operators in certain domain of parameter space and “p-deformed volumes”, which are certain integral transforms of topological recursion data, is described and clarified. This identification allows us to efficiently study correlation numbers at finite matter central charge. In particular, we obtain an intersection-theoretic formula and the simplest recurrent equations for them, analogous to the ones recently derived for Virasoro minimal string. These formulas might be useful in establishing a more thorough connection between worldsheet and matrix model approaches.