bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analytical evaluation of AdS4 Witten diagrams as flat space multi-loop Feynman integrals
Authors: Heckelbacher Till , Sachs Ivo , Skvortsov Evgeny , Vanhove Pierre 
Published: August 2022

Abstract
We describe a systematic approach for the evaluation of Witten diagrams for multi-loop scattering amplitudes of a conformally coupled scalar ϕ4-theory in Euclidean AdS4, by recasting the Witten diagrams as flat space Feynman integrals. We derive closed form expressions for the anomalous dimensions for all double-trace operators up to the second order in the coupling constant. We explain the relation between the flat space unitarity methods and the discontinuities of the short distance expansion on the boundary of Witten diagrams.
NLO QCD corrections to full off-shell production of $$ t\overline{t}Z $$ including leptonic decays
Authors: Bevilacqua Giuseppe , Hartanto Heribertus Bayu , Kraus Manfred , Nasufi Jasmina , Worek Malgorzata 
Published: August 2022

Abstract
Motivated by ongoing new physics searches in the top-quark sector at the Large Hadron Collider we report on the calculation of NLO QCD corrections to the Standard Model pp → $$ t\overline{t}Z $$
t

t
¯

Z
+ X process in the tetra-lepton decay channel. This calculation is based on the matrix elements for the $$ {e}^{+}{\nu}_e{\mu}^{-}{\overline{\nu}}_{\mu }b\overline{b}{\tau}^{+}{\tau}^{-} $$

e
+

ν
e

μ
−

ν
¯

μ

b

b
¯

τ
+

τ
−

final state and includes all resonant and non-resonant Feynman diagrams, interferences and off-shell effects of the top quark as well as the W and Z gauge bosons. Also incorporated are photon-induced contributions. As it is customary for such studies, we show theoretical predictions for both fixed and dynamical factorisation and renormalisation scale choices and different PDF sets. Furthermore, we study the main theoretical uncertainties that are associated with neglected higher-order terms in the perturbative expansion and with the parameterisation of the PDF sets. In order to investigate the size of off-shell effects and higher-order corrections in top-quark decays, we perform a second computation for this process, which is based on the narrow-width-approximation where the top quarks, W and Z gauge bosons are kept on-shell. Results are given for the integrated and differential fiducial cross sections for the LHC Run II center-of-mass energy of 13 TeV.
The entanglement wedge of unknown couplings
Authors: Almheiri Ahmed , Lin Henry W. 
Published: August 2022

Abstract
The black hole interior is a mysterious region of spacetime where non-perturbative effects are sometimes important. These non-perturbative effects are believed to be highly theory-dependent. We sharpen these statements by considering a setup where the state of the black hole is in a superposition of states corresponding to boundary theories with different couplings, entangled with a reference which keeps track of those couplings. The entanglement wedge of the reference can then be interpreted as the bulk region most sensitive to the values of the couplings. In simple bulk models, e.g., JT gravity + a matter BCFT, the QES formula implies that the reference contains the black hole interior at late times. We also analyze the Renyi-2 entropy tr ρ2 of the reference, which can be viewed as a diagnostic of chaos via the Loschmidt echo. We find explicitly the replica wormhole that diagnoses the island and restores unitarity. Numerical and analytical evidence of these statements in the SYK model is presented. Similar considerations are expected to apply in higher dimensional AdS/CFT, for marginal and even irrelevant couplings.
Complex saddles and Euclidean wormholes in the Lorentzian path integral
Authors: Loges Gregory J. , Shiu Gary , Sudhir Nidhi 
Published: August 2022

Abstract
We study complex saddles of the Lorentzian path integral for 4D axion gravity and its dual description in terms of a 3-form flux, which include the Giddings-Strominger Euclidean wormhole. Transition amplitudes are computed using the Lorentzian path integral and with the help of Picard-Lefschetz theory. The number and nature of saddles is shown to qualitatively change in the presence of a bilocal operator that could arise, for example, as a result of considering higher-topology transitions. We also analyze the stability of the Giddings-Strominger wormhole in the 3-form picture, where we find that it represents a perturbatively stable Euclidean saddle of the gravitational path integral. This calls into question the ultimate fate of such solutions in an ultraviolet-complete theory of quantum gravity.
The cost of building a wall for a fermion
Authors: Wan Mokhtar Wan Mohamad Husni , Louko Jorma 
Published: August 2022

Abstract
We analyse the energy cost of building or demolishing a wall for a massless Dirac field in (1+1)-dimensional Minkowski spacetime and the response of an Unruh-DeWitt particle detector to the generated radiation. For any smoothly-evolving wall, both the field’s energy density and the detector’s response are finite. In the limit of rapid wall creation or demolition, the energy density displays a delta function squared divergence. By contrast, the response of an Unruh-DeWitt detector, evaluated within first-order perturbation theory, diverges only logarithmically in the duration of the wall evolution. The results add to the evidence that a localised matter system may not be as sensitive to the rapid wall creation as the local expectation values of field observables. This disparity has potential interest for quantum information preservation scenarios.
Alpha states demystified — towards microscopic models of AdS2 holography
Authors: Blommaert Andreas , Iliesiu Luca V. , Kruthoff Jorrit 
Published: August 2022

Abstract
We continue our study of factorizing theories of dilaton gravity, characterized by a universal bilocal interaction. All such factorizing theories can be shown to have discrete spectra, distinguished only by their local dilaton potentials. We show how such theories can be used to construct all alpha-states in the Hilbert space of baby universes of ordinary JT gravity. Large classes of these theories with different local potentials are found to be non-perturbatively equivalent and have identical discrete spectra. This is a concrete example of how different bulk descriptions can give rise to the same boundary theory. Such equivalences manifest themselves as null states, which have to be quotiented out in order to construct a proper baby universe Hilbert space. Our results also allow us to revisit the mechanism discussed by Coleman, Giddings and Strominger and concretely link ensemble averaging to the appearance or disappearance of spacetime wormholes.We then investigate JT gravity deformed only by the universal bilocal interaction. In this theory, the only terms that do not cancel in a topological expansion are disks, which capture perturbative fluctuations around a two-dimensional black hole saddle. We find that this theory of black holes has an evenly spaced spectrum, instead of a quantum chaotic one. We present a dual quantum mechanical system with exactly the same discrete spectrum, and propose that this is an example of a new holographic duality between a two-dimensional theory of quantum gravity and a conventional quantum mechanics.
Higgs boson decay to charmonia via c-quark fragmentation
Authors: Han Tao , Leibovich Adam K. , Ma Yang , Tan Xiao-Ze 
Published: August 2022

Abstract
We calculate the decay branching fractions of the Higgs boson to J/ψ and ηc via the charm-quark fragmentation mechanism for the color-singlet and color-octet states in the framework of non-relativistic QCD. The decay rates are governed by the charm-quark Yukawa coupling, unlike the decay H → J/ψ + γ, which is dominated by the γ∗-J/ψ mixing. We find that the decay branching fractions can be about 2×10−5 for $$ H\to c\overline{c}+J/\psi $$
H
→
c

c
¯

+
J
/
ψ
, and 6 × 10−5 for $$ H\to c\overline{c}+{\eta}_c $$
H
→
c

c
¯

+

η
c

. We comment on the perspective of searching for the Higgs boson to J/ψ transition at the High-Luminosity LHC for testing the charm-quark Yukawa coupling.
DC conductance and memory in 3D gravity
Authors: Cárdenas Márcela , González Hernán A. , Lara Kristiansen , Pino Miguel 
Published: August 2022

Abstract
Transport properties are investigated in the two-dimensional dual dynamics of AdS3 gravity. By providing boundary conditions that deform the ADM lapse and shift functions, we construct a lower dimensional model comprising two copies of chiral boson excitations with anisotropic scaling symmetry. Using bosonization, an electric current is identified. By means of the Kubo formula, we find a DC conductance depending on the level of the theory and the dynamical exponents. The bulk realization of the linear response is related to a type of gravitational memory emerging in the context of near-horizon boundary conditions. The process is adiabatic and represents a permanent spacetime deformation parametrized by anisotropic chiral bosons through a large gauge transformation.
Improved cosmological constraints on the neutrino mass and lifetime
Authors: Abellán Guillermo Franco , Chacko Zackaria , Dev Abhish , Du Peizhi , Poulin Vivian , Tsai Yuhsin 
Published: August 2022

Abstract
We present cosmological constraints on the sum of neutrino masses as a function of the neutrino lifetime, in a framework in which neutrinos decay into dark radiation after becoming non-relativistic. We find that in this regime the cosmic microwave background (CMB), baryonic acoustic oscillations (BAO) and (uncalibrated) luminosity distance to supernovae from the Pantheon catalog constrain the sum of neutrino masses ∑mν to obey ∑mν< 0.42 eV at (95% C.L.). While the bound has improved significantly as compared to the limits on the same scenario from Planck 2015, it still represents a significant relaxation of the constraints as compared to the stable neutrino case. We show that most of the improvement can be traced to the more precise measurements of low-ℓ polarization data in Planck 2018, which leads to tighter constraints on τreio (and thereby on As), breaking the degeneracy arising from the effect of (large) neutrino masses on the amplitude of the CMB power spectrum.
CD69-oxLDL ligand engagement induces Programmed Cell Death 1 (PD-1) expression in human CD4 + T lymphocytes
Authors: Jiménez-Fernández María , Rodríguez-Sinovas Cristina , Cañes Laia , Ballester-Servera Carme , Vara Alicia , Requena Silvia , de la Fuente Hortensia , Martínez-González José , Sánchez-Madrid Francisco 
Published: August 2022

AbstractThe mechanisms that control the inflammatory–immune response play a key role in tissue remodelling in cardiovascular diseases. T cell activation receptor CD69 binds to oxidized low-density lipoprotein (oxLDL), inducing the expression of anti-inflammatory NR4A nuclear receptors and modulating inflammation in atherosclerosis. To understand the downstream T cell responses triggered by the CD69-oxLDL binding, we incubated CD69-expressing Jurkat T cells with oxLDL. RNA sequencing revealed a differential gene expression profile dependent on the presence of CD69 and the degree of LDL oxidation. CD69-oxLDL binding induced the expression of NR4A receptors (NR4A1 and NR4A3), but also of PD-1. These results were confirmed using oxLDL and a monoclonal antibody against CD69 in CD69-expressing Jurkat and primary CD4 + lymphocytes. CD69-mediated induction of PD-1 and NR4A3 was dependent on NFAT activation. Silencing NR4A3 slightly increased PD-1 levels, suggesting a potential regulation of PD-1 by this receptor. Moreover, expression of PD-1, CD69 and NR4A3 was increased in human arteries with chronic inflammation compared to healthy controls, with a strong correlation between PD-1 and CD69 mRNA expression (r = 0.655 P < 0.0001). Moreover, PD-1 was expressed in areas enriched in CD3 infiltrating T cells. Our results underscore a novel mechanism of PD-1 induction independent of TCR signalling that might contribute to the role of CD69 in the modulation of inflammation and vascular remodelling in cardiovascular diseases.
Perverse Sheaves with Nilpotent Singular Support on the Stack of Coherent Sheaves on an Elliptic Curve
Authors: Hennecart Lucien 
Published: August 2022

AbstractWe define a stratification of the moduli stack of coherent sheaves on an elliptic curve which allows us (1) to give an explicit description of the irreducible components of the global nilpotent cone of elliptic curves, (2) to establish an explicit bijection between the simple objects of the category of perverse sheaves defined by Schiffmann to categorify the elliptic Hall algebra (the so-called spherical Eisenstein sheaves) and the irreducible components of the global nilpotent cone and (3) to give an explicit description and parametrization of the perverse sheaves on the moduli stack of coherent sheaves on an elliptic curve having nilpotent singular support. Along the way, we find a combinatorial parametrization of the irreducible components of the semistable locus of the elliptic global nilpotent cone. The comparison with Bozec’s parametrization leads to an interesting combinatorial problem.
Some Subcritical Estimates for the $$\ell ^p$$-Improving Problem for Discrete Curves
Authors: Dendrinos Spyridon , Hughes Kevin , Vitturi Marco 
Published: August 2022

AbstractWe apply Christ’s method of refinements to the $$\ell ^p$$

ℓ
p

-improving problem for discrete averages $${\mathcal {A}}_N$$

A
N

along polynomial curves in $${\mathbb {Z}}^d$$

Z

d

. Combined with certain elementary estimates for the number of solutions to certain special systems of diophantine equations, we obtain some restricted weak-type $$p \rightarrow p'$$

p
→

p
′

estimates for the averages $${\mathcal {A}}_N$$

A
N

in the subcritical regime. The dependence on N of the constants here obtained is sharp, except maybe for an $$\epsilon $$
ϵ
-loss.
Surgical hip dislocation with relative femoral neck lengthening and retinacular soft-tissue flap for sequela of Legg–Calve–Perthes disease
Authors: Leibold Christiane Sylvia , Vuillemin Nicolas , Büchler Lorenz , Siebenrock Klaus Arno , Steppacher Simon Damian 
Published: August 2022

Abstract
Objective
Correction of post-LCP (Legg–Calve–Perthes) morphology using surgical hip dislocation with retinacular flap and relative femoral neck lengthening for impingent correction reduces the risk of early arthritis and improves the survival of the native hip joint.

Indications
Typical post-LCP deformity with external and internal hip impingement due to aspherical enlarged femoral head and shortened femoral neck with high riding trochanter major without advanced osteoarthritis (Tönnis classification ≤ 1) in the younger patient (age < 50 years).

Contraindications
Advanced global osteoarthritis (Tönnis classification ≥ 2).

Surgical technique
By performing surgical hip dislocation, full access to the hip joint is gained which allows intra-articular corrections like cartilage and labral repair. Relative femoral neck lengthening involves osteotomy and distalization of the greater trochanter with reduction of the base of the femoral neck, while maintaining vascular perfusion of the femoral head by creation of a retinacular soft-tissue flap.

Postoperative management
Immediate postoperative mobilization on a passive motion device to prevent capsular adhesions. Patients mobilized with partial weight bearing of 15 kg with the use of crutches for at least 8 weeks.

Results
In all, 81 hips with symptomatic deformity of the femoral head after healed LCP disease were treated with surgical hip dislocation and offset correction between 1997 and 2020. The mean age at operation was 23 years; mean follow-up was 9 years; 11 hips were converted to total hip arthroplasty and 1 patient died 1 year after the operation. The other 67 hips showed no or minor progression of arthrosis. Complications were 2 subluxations due to instability and 1 pseudarthrosis of the lesser trochanter; no hip developed avascular necrosis.
Design, modeling, and control of a variable stiffness elbow joint
Authors: Baggetta Mario , Berselli Giovanni , Palli Gianluca , Melchiorri Claudio 
Published: August 2022

AbstractNew technological advances are changing the way robotics are designed for safe and dependable physical human–robot interaction and human-like prosthesis. Outstanding examples are the adoption of soft covers, compliant transmission elements, and motion control laws that allow compliant behavior in the event of collisions while preserving accuracy and performance during motion in free space. In this scenario, there is growing interest in variable stiffness actuators (VSAs). Herein, we present a new design of an anthropomorphic elbow VSA based on an architecture we developed previously. A robust dynamic feedback linearization algorithm is used to achieve simultaneous control of the output link position and stiffness. This actuation system makes use of two compliant transmission elements, characterized by a nonlinear relation between deflection and applied torque. Static feedback control algorithms have been proposed in literature considering purely elastic transmission; however, viscoelasticity is often observed in practice. This phenomenon may harm the performance of static feedback linearization algorithms, particularly in the case of trajectory tracking. To overcome this limitation, we propose a dynamic feedback linearization algorithm that explicitly considers the viscoelasticity of the transmission elements, and validate it through simulations and experimental studies. The results are compared with the static feedback case to showcase the improvement in trajectory tracking, even in the case of parameter uncertainty.
Estimating policy-corrected long-term and short-term tax elasticities for the USA, Germany, and the United Kingdom
Authors: Hayo Bernd , Mierzwa Sascha , Ünal Umut 
Published: August 2022

AbstractWe estimate the elasticities of the most important tax categories using a new quarterly database of discretionary tax measures for the USA, Germany, and the United Kingdom over the period 1980Q1 to 2018Q2. Employing Romer and Romer’s (2009) narrative approach, we construct a policy-neutral dataset based on revenue figures from governmental records. Using this quantitative information, we are able to subtract policy-induced changes, which often are not considered in the literature. Furthermore, we estimate state-dependent elasticities. Our conclusions are as follows. (i) In Germany and the UK, long-term tax-to-base elasticities are generally higher than short-term elasticities, whereas results for the USA are mixed. (ii) Short-term base-to-output elasticities tend to be smaller than unity, whereas long-term elasticities are close to unity. (iii) German and UK tax-to-output elasticities in the short term are lower than long-term elasticities, with mixed results for the USA. (iv) For tax-to-base elasticities, we find business-cycle asymmetries across countries but not within countries. (v) For base-to-output elasticities, our results suggest few asymmetries across countries and more asymmetries across tax types. (vi) Typically, the above conclusions do not hold for corporate income tax.
Dual labor market and the “Phillips curve puzzle”: the Japanese experience
Authors: Aoyama Hideaki , Di Guilmi Corrado , Fujiwara Yoshi , Yoshikawa Hiroshi 
Published: August 2022

AbstractLow inflation was once welcomed by both policymakers and the public. However, Japan’s experience during the 1990s changed the consensus of economists and central banks around the world regarding prices. Facing deflation and the zero-interest bound at the same time, the Bank of Japan had difficulty conducting an effective monetary policy, making Japan’s stagnation unusually prolonged. The too-low inflation that concerns central banks today translates into the “Phillips curve puzzle.” In the United States and Japan, in the course of the recovery from the Great Recession after the 2008 Global Financial Crisis, the unemployment rate had steadily declined to a level commonly regarded as lower than the natural rate or NAIRU. However, inflation remained low. In this paper, we consider a minimal model of the dual labor market to jointly investigate how the different factors affecting the structural evolution of the labor market have contributed to the observed flattening of the Phillips curve. We find that the level of bargaining power of workers, elasticity of the supply of labor to wage in the secondary market, and composition of the workforce are the main factors jointly explaining the evidence for Japan.
Age-related asymmetry in anticipatory postural movements during unilateral arm movement and imagery
Authors: Wider Chloe , Mitra Suvobrata , Boulton Hayley , Andrews Mark 
Published: August 2022

AbstractReaching movements of the arms are accompanied by anticipatory (APM) and compensatory postural motion (CPM) that counteract the resulting perturbations to body stability. Recent research has shown that these postural actions are also observable in the context of imagined arm movements. As motor imagery (MI) shares many neurophysiological and behavioral characteristics with physical movements, and MI training can affect subsequent performance, MI tasks provide a good setting for studying the anticipatory aspects of postural control. This study investigated APMs and CPMs of the head and hip of healthy young and older adults in the temporal vicinity of physical and imagined forward raises of the dominant and non-dominant arm. When MI of the dominant arm was self-initiated, both age groups showed APM in the anteroposterior plane. When the self-initiated MI was of the non-dominant arm, only the older group showed anteroposterior APM. The older group did not show APM when an expected arm movement (or MI) was made to an external signal. This suggests an age-related deficit in coordinating postural preparation with external events. Only the older group showed mediolateral APM, and only for dominant arm MI, indicating sensitivity to potential perturbation to the weaker, non-dominant side of the body. Overall, the older group showed more anticipatory postural motion at the head. Systematic APM for manual MI suggests that MI training may be an effective intervention for anticipatory postural control. An integrated model of postural support for executed and imagined limb movements is suggested.
Surface evolution of crystalline SrTiO3, LaAlO3 and Y3Al5O12 targets during pulsed laser ablation
Authors: Jung Florian , Delmdahl Ralph , Heymann Andreas , Fischer Max , Karl Helmut 
Published: August 2022

AbstractPulsed laser ablation and deposition find applications in various technological and scientific fields, where precise control of the laser target interaction is crucial for achieving reproducible results. In this work, we investigated pulsed laser ablation of single crystalline (001), (011) and (111) oriented SrTiO3 (STO), (102) LaAlO3 (LAO) and (001) Y3Al5O12 (YAG) targets. The morphology, oxygen loss, and crack formation on the target surfaces after irradiation with a series of KrF excimer laser pulses will be discussed. The target surface morphology was imaged by atomic force, scanning electron microscopy and confocal laser scanning microscopy. Electron backscatter diffraction analysis and energy-dispersive X-ray spectroscopy were used to analyze the crystallographic changes of the surface and the elemental composition. The target material STO shows a significant crack formation and layer separation increasing with surface crystal orientation from (001) through (011) to (111) and laser pulse fluence. In contrast, the laser-ablated surfaces of LAO show only thin hairline cracks and YAG stays free of cracks in the whole laser fluence range investigated but presents large chipped areas.