bluuebunny/crossref_metadata_2025_split huggingface dataset:
L

q
-spectra of graph-directed planar non-conformal measures
Authors: Qiu Hua , Wang Qi , Wang Shufang 
Published: July 2024

Abstract
We estimate the upper and lower Lq
-spectra of measures generated by a class of graph-directed planar non-conformal iterated function systems. These systems are composed of

C

1
+
ϵ

contractions with lower triangular pointwise Jacobian. The estimation provides a criterion for the existence of the Lq
-spectra in certain case. As an application, we derive the box-counting dimension of planar self-affine sets generated by lower triangular matrices, whose geometric construction satisfies a finite overlapping type condition.
Scaling laws and exact results in turbulence
*
Authors: Novack Matthew 
Published: July 2024

Abstract
In this note, we address the validity of certain exact results from turbulence theory in the deterministic setting. The main tools, inspired by the work of Duchon and Robert (2000 Nonlinearity
13 249–55) and Eyink (2003 Nonlinearity
16 137), are a number of energy balance identities for weak solutions of the incompressible Euler and Navier–Stokes equations. As a consequence, we show that certain weak solutions of the Euler and Navier–Stokes equations satisfy deterministic versions of Kolmogorov’s

4
5

,

4
3

,

4
15

laws. We apply these computations to improve a recent result of Hofmanova et al (2023 arXiv:2304.14470), which shows that a construction of solutions of forced Navier–Stokes due to Bruè et al (2023 Commun. Pure Appl. Anal.) and exhibiting a form of anomalous dissipation satisfies asymptotic versions of Kolmogorov’s laws. In addition, we show that the globally dissipative 3D Euler flows recently constructed by Giri et al (2023 arXiv:2305.18509) satisfy the local versions of Kolmogorov’s laws.
Atwood machine automation using Arduino and LabVIEW
Authors: Indratno T K , Prasetya Y D , Prabowo Y D , Sukarelawan M I 
Published: July 2024

Abstract
The Atwood machine is an apparatus used in physics experiments to visualize the concept of Newton’s Second Law of Motion. However, the data collection on the Atwood machine, which is still done manually using a stopwatch, may cause errors and can be time-consuming. To improve the efficiency and accuracy of the experiment, this research developed Atwood machine automation using Arduino Uno microcontroller. The automation enables automatic release of weights and automatic data collection through a graphical user interface developed using LabVIEW. The experiment using the automated machine obtained satisfactory results in verifying the earth’s gravitational acceleration. Therefore, this machine can be used in physics learning, especially in physics experiment. The automation also enables remote utilization through internet connection, thus allowing easier and wider access for users.
A deep-learning-based surrogate model for Monte-Carlo simulations of the linear energy transfer in primary brain tumor patients treated with proton-beam radiotherapy
Authors: Starke Sebastian , Kieslich Aaron , Palkowitsch Martina , Hennings Fabian , G C Troost Esther , Krause Mechthild , Bensberg Jona , Hahn Christian , Heinzelmann Feline , Bäumer Christian , Lühr Armin , Timmermann Beate , Löck Steffen 
Published: July 2024

Abstract

Objective. This study explores the use of neural networks (NNs) as surrogate models for Monte-Carlo (MC) simulations in predicting the dose-averaged linear energy transfer (LET
d
) of protons in proton-beam therapy based on the planned dose distribution and patient anatomy in the form of computed tomography (CT) images. As LET
d
is associated with variability in the relative biological effectiveness (RBE) of protons, we also evaluate the implications of using NN predictions for normal tissue complication probability (NTCP) models within a variable-RBE context. Approach. The predictive performance of three-dimensional NN architectures was evaluated using five-fold cross-validation on a cohort of brain tumor patients (n = 151). The best-performing model was identified and externally validated on patients from a different center (n = 107). LET
d
predictions were compared to MC-simulated results in clinically relevant regions of interest. We assessed the impact on NTCP models by leveraging LET
d
predictions to derive RBE-weighted doses, using the Wedenberg RBE model. Main results. We found NNs based solely on the planned dose distribution, i.e. without additional usage of CT images, can approximate MC-based LET
d
distributions. Root mean squared errors (RMSE) for the median LET
d
within the brain, brainstem, CTV, chiasm, lacrimal glands (ipsilateral/contralateral) and optic nerves (ipsilateral/contralateral) were 0.36, 0.87, 0.31, 0.73, 0.68, 1.04, 0.69 and 1.24 keV µm−1, respectively. Although model predictions showed statistically significant differences from MC outputs, these did not result in substantial changes in NTCP predictions, with RMSEs of at most 3.2 percentage points. Significance. The ability of NNs to predict LET
d
based solely on planned dose distributions suggests a viable alternative to compute-intensive MC simulations in a variable-RBE setting. This is particularly useful in scenarios where MC simulation data are unavailable, facilitating resource-constrained proton therapy treatment planning, retrospective patient data analysis and further investigations on the variability of proton RBE.
Impact of optimized transcutaneous auricular vagus nerve stimulation on cardiac autonomic profile in healthy subjects and heart failure patients
Authors: Maestri Roberto , Pinna Gian Domenico , Robbi Elena , Cogliati Chiara , Bartoli Arianna , Gambino Giuseppina , Rengo Giuseppe , Montano Nicola , La Rovere Maria Teresa 
Published: July 2024

Abstract

Objective. To determine the optimal frequency and site of stimulation for transcutaneous vagus nerve stimulation (tVNS) to induce acute changes in the autonomic profile (heart rate (HR), heart rate variability (HRV)) in healthy subjects (HS) and patients with heart failure (HF). Approach. We designed three single-blind, randomized, cross-over studies: (1) to compare the acute effect of left tVNS at 25 Hz and 10 Hz (n = 29, age 60 ± 7 years), (2) to compare the acute effect of left and right tVNS at the best frequency identified in study 1 (n = 28 age 61 ± 7 years), and (3) to compare the acute effect of the identified optimal stimulation protocol with sham stimulation in HS and HF patients (n = 30, age 59 ± 5 years, and n = 32, age 63 ± 7 years, respectively). Main results. In study 1, left tragus stimulation at 25 Hz was more effective than stimulation at 10 Hz in decreasing HR (−1.0 ± 1.2 bpm, p < 0.001 and −0.5 ± 1.6 bpm, respectively) and inducing vagal effects (significant increase in RMSSD, and HF power). In study 2, the HR reduction was greater with left than right tragus stimulation (−0.9 ± 1.5 bpm, p < 0.01 and −0.3 ± 1.4 bpm, respectively). In study 3 in HS, left tVNS at 25 Hz significantly reduced HR, whereas sham stimulation did not (−1.1 ± 1.2 bpm, p< 0.01 and −0.2 ± 2.9 bpm, respectively). In HF patients, both active and sham stimulation produced negligible effects. Significance. Left tVNS at 25 Hz is effective in acute modulation of cardiovascular autonomic control (HR, HRV) in HS but not in HF patients (NCT05789147).
Experimental and simulation study of argon helicon discharge in multiple plasma simulation linear device (MPS-LD)
Authors: Wu Jintao , Sang Chaofeng , Sun Changjiang , Sun Bin , Gao Shuaishuai , Bian Yu , Peng Yao , Wang Qi , Wang Dezhen 
Published: July 2024

Abstract
To obtain a high-parameter plasma in the target region of a multiple plasma simulation linear device and to realize the experimental simulation environment of tokamak divertor plasma, experimental and numerical simulations of argon helicon discharge are carried out. Langmuir probes are used to diagnose the electron density (ne
) in the source and target regions with different experimental parameters (magnetic field, radio frequency power, puffing flow rate). A three-dimensional discharge model is developed using drift-diffusion equations of electron density and electron energy with the aid of COMSOL. Helicon discharge with a long straight plasma beam and a bright blue core is experimentally achieved. The simulation and experimental results are compared, validating the model. The corresponding spatial ne
distribution is obtained, and the dependence of ne
on the main experimental parameters is confirmed. The energy conversion relationship between the helicon and plasma is found. Helicon waves prefer to transfer energy to the plasma in the source region, where ne
is significantly increased. This results in a strong ne
gradient, which acts as a barrier to prevent the propagation of helicon waves. Therefore, localized standing helicon waves are formed, which limits the increase in plasma density in the target region. By increasing the magnetic field strength (B < 1500 G) and RF power (P < 1500 W), ne
in the source region can be increased, but they have little effect on ne
in the target region.
Liquid-to-gas transfer of sodium in a liquid cathode glow discharge
Authors: Srivastava Tanubhav , Dogariu Arthur , Morozov Anatoli , Bruggeman Peter 
Published: July 2024

Abstract
Plasma-liquid interactions have been extensively studied with a focus on the transport of reactive species from the plasma to the liquid phase and their induced liquid phase chemistry and resulting applications. While solute transfer from the liquid to the gas phase in plasmas has been widely used in analytical chemistry, the underlying processes remain relatively unexplored. We report spatially and temporally resolved absolute density measurements of sodium in a plasma with a NaCl solution cathode using two-photon absorption laser induced fluorescence (TaLIF). The observed non-linear increase in sodium density with solution conductivity is shown to correlate with droplet generation as visualized by Mie scattering. The findings are explained by droplet generation by electrospray induced by Taylor cone formation as underpinning mechanism for the introduction of sodium in the plasma. An analytical sheath model combined with a scaling law shows an increase in electric field force with solution conductivity that is consistent with the observed non-linear increase in sodium density in the plasma with solution conductivity.
Phononic crystals with incomplete line defects: applications in high-performance and broadband acoustic energy localization and harvesting
Authors: Zhang Guo-Yu , Liu Zi-Jiang , Li Bing-Zu , Dou Xi-Long , Zhang Cai-Rong , Sun Xiao-Wei , Yang Yi-Man 
Published: July 2024

Abstract
Using phononic crystals (PnCs) to enhance the electrical output performance of piezoelectric energy harvesting (PEH) devices and broaden the frequency range of harvesting energy is crucial to solving the self-energy of low-power devices such as wireless sensors. In this work, an ultra-wide full-band gap PnC was designed. The concept of a PnC with an incomplete line defect was proposed. The energy localization and harvesting of incomplete line defect PnCs and traditional point defect and line defect PnCs were studied by finite element analysis. The results show that compared with a point defect and a line defect, the output electric power of an incomplete line defect was increased by 31.88 times and 2.51 times, respectively, and the energy localization and harvesting frequency band were widened. By exploring the influence of the periodicity of the vertical incomplete line defect direction on the electrical output performance of the PnC-based PEH system, it is found that the electrical output performance of the 5 × 3 incomplete line defect PnC is the best, and the maximum output voltage and output electric power are 27.36 V and 17.29 mW, respectively. This work provides new insights and ideas for improving the energy localization and harvesting performance of PnC-based PEH systems.
Is the dynamical quantum Cheshire cat detectable?
Authors: Hance Jonte R , Ladyman James , Rarity John 
Published: July 2024

Abstract
We explore how one might detect the dynamical quantum Cheshire cat proposed by Aharonov et al We show that, in practice, we need to bias the initial state by adding/subtracting a small probability amplitude (‘field’) of the orthogonal state, which travels with the disembodied property, to make the effect detectable (i.e. if our initial state is

|

↑
z

⟩

, we need to bias this with some small amount δ of state

|

↓
z

⟩

). This biasing, which can be done either directly or via weakly entangling the state with a pointer, effectively provides a phase reference with which we can measure the evolution of the state. The outcome can then be measured as a small probability difference in detections in a mutually unbiased basis, proportional to this biasing δ. We show this is different from counterfactual communication, which provably does not require any probe field to travel between sender Bob and receiver Alice for communication. We further suggest an optical polarisation experiment where these phenomena might be demonstrated in a laboratory.
Directional pre-sensitivity of the laser interferometer space antenna
Authors: Riegger F , Andersson F , Robertsson J 
Published: July 2024

Abstract
The space-based Laser Interferometry Space Antenna (LISA) is a gravitational waves observatory currently under development. It comprises three spacecraft, each traveling in a heliocentric orbit that is weakly eccentric and inclined. Gravitational waves comprise two polarization components. They will be detected by conducting interferometric Doppler measurements between the LISA spacecraft. Among other factors, the signal strength of the Doppler measurements will depend on the location of the GW source, the GW polarization angle, and the orbits of the spacecraft. Thus, the signal strength of the Doppler measurements will vary over time. For given spacecraft orbits, we derive bounds on the signal strength that are functions of the source location. These bounds are simple, explicit expressions, and we refer to them as the directional pre-sensitivity. Using the directional pre-sensitivity, we construct a metric for the relative change in the signal strength depending on the source location and the spacecraft orbits. We illustrate how this formalism can be used to assess the signal strength for several examples of chosen orbits.
Coupling elastic media to gravitational waves: an effective field theory approach
Authors: Belgacem Enis , Maggiore Michele , Moreau Thomas 
Published: July 2024

Abstract
The interaction of a gravitational wave (GW) with an elastic body is usually described in terms of a GW “force” driving the oscillations of the body's normal modes. However, this description is only possible for GW frequencies for which the response of the elastic body is dominated by a few normal modes. At higher frequencies the normal modes blend into a quasi-continuum and a field-theoretical description, as pioneered by Dyson already in 1969, becomes necessary. However, since the metric perturbation hμν
is an intrinsically relativistic object, a consistent coupling to GWs can only be obtained within a relativistic (and, in fact generally covariant) theory of elasticity. We develop such a formalism using the methods of modern effective field theories, and we use it to
provide a derivation of the interaction of elastic bodies with GWs valid also in the high-frequency regime, providing a first-principle derivation of Dyson's result (and partially correcting it).
We also stress that the field-theoretical results are obtained
working in the TT frame, while the description in terms of a force driving the normal modes is only valid in the proper detector frame. We show how to transform the results between the two frames. Beside an intrinsic conceptual interest, these results are relevant to the computation of the sensitivity of the recently proposed Lunar Gravitational Wave Antenna.
Dark radiation isocurvature from cosmological phase transitions
Authors: Buckley Matthew R. , Du Peizhi , Fernandez Nicolas , Weikert Mitchell J. 
Published: July 2024

Abstract
Cosmological first order phase transitions are typically associated with physics beyond the Standard Model, and thus of great theoretical and observational interest. Models of phase transitions where the energy is mostly converted to dark radiation can be constrained through limits on the dark radiation energy density (parameterized by ΔN
eff). However, the current constraint (ΔN
eff < 0.3) assumes the perturbations are adiabatic. We point out that a broad class of non-thermal first order phase transitions that start during inflation but do not complete until after reheating leave a distinct imprint in the scalar field from bubble nucleation. Dark radiation inherits the perturbation from the scalar field when the phase transition completes, leading to large-scale isocurvature that would be observable in the CMB. We perform a detailed calculation of the isocurvature power spectrum and derive constraints on ΔN
eff based on CMB+BAO data. For a reheating temperature of T
rh and a nucleation temperature T
*, the constraint is approximately ΔN
eff ≲ 10-5 (T
*/T
rh)-4, which can be much stronger than the adiabatic result. We also point out that since perturbations of dark radiation have a non-Gaussian origin, searches for non-Gaussianity in the CMB could place a stringent bound on ΔN
eff as well.
Analytical perturbations of relativistic images in Kerr space-time
Authors: Aratore Fabio , Bozza Valerio 
Published: July 2024

Abstract
Light rays passing very close to black holes may wind several times before escaping. For any given electromagnetic source around the black hole, a distant observer would thus observe two infinite sequences of images on either side of the black hole. These images are generated by light rays performing an increasing numbers of loops. The strong deflection limit provides a simple analytic formalism to describe such higher order images for spherically symmetric metrics, while for axially symmetric black holes one typically resorts to numerical approaches. Here we present the leading order perturbation to higher order images when the black hole spin is turned on. We show that the images slide around the black hole shadow as an effect of space-time dragging. We derive analytical formulae for their shifts and the perturbation of their time delays. We also discuss how such simple analytical formulae for images by Kerr black holes can be of great help in many applications.
Realisation of the ultra-slow roll phase in Galileon inflation and PBH overproduction
Authors: Choudhury Sayantan , Karde Ahaskar , Panda Sudhakar , Sami M. 
Published: July 2024

AbstractWe demonstrate the explicit realisation of the ultra-slow roll phase in the framework of the effective field theory of single-field Galileon inflation. The pulsar timing array (PTA) collaboration hints at the scalar-induced gravity waves (SIGW) from the early universe as an explanation for the origin of the observed signal, which, however, leads to an enhancement in the amplitude of the scalar power spectrum giving rise to the overproduction of primordial black holes (PBHs). In the setup under consideration, we examine the generation of SIGW consistent with PTA (NANOGrav15 and EPTA) data, in addition to which we also consider the impact from QCD crossover at the nHz frequencies and address the PBH overproduction issue assuming linear approximations for the over-density without incorporating non-Gaussian effects from the comoving curvature perturbation. The framework is shown to give rise to SIGWs well consistent with the PTA signal with comfortable PBH abundance, 10-3≲fPBH < 1, of near solar-mass black holes.
Casimir wormholes inspired by electric charge in Einstein–Gauss–Bonnet gravity
Authors: Farooq Mushayydha , Zubair M , H Alkhaldi Ali , Ali Akram 
Published: July 2024

Abstract
This investigation assesses the feasibility of a traversable wormhole by examining the energy densities associated with charged Casimir phenomena. We focus on the influence of the electromagnetic field created by an electric charge as well as the negative energy density arising from the Casimir source. We have developed different shape functions by defining energy densities from this combination. This paper explores various configurations of Casimir energy densities, specifically those occurring between parallel plates, cylinders and spheres positioned at specified distances from each other. Furthermore, the impact of the generalized uncertainty principle correction is also examined. The behavior of wormhole conditions is evaluated based on the Gauss–Bonnet coupled parameter (μ) and electric charge (Q) through the electromagnetic energy density constraint. This is attributed to the fact that the electromagnetic field satisfies the characteristic ρ = −p

r
. Subsequently, we examine the active gravitational mass of the generated wormhole geometries and explore the behavior of μ and Q concerning active mass. The embedding representations for all formulated shape functions are examined. Investigations of the complexity factor of the charged Casimir wormhole have demonstrated that the values of the complexity factor consistently fall within a particular range in all scenarios. Finally, using the generalized Tolman–Oppenheimer–Volkoff equation, we examine the stability of the resulting charged Casimir wormhole solutions.
Probing inelastic signatures of dark matter detection via polarized nucleus*
Authors: Yun 云 Zai 在 , Sun 孙 Junwei 俊伟 , Zhu 祝 Bin 斌 , Liu 刘 Xuewen 学文 
Published: July 2024

Abstract
We investigate the inelastic signatures of dark matter-nucleus interactions, explicitly focusing on the ramifications of polarization, dark matter splitting, and the Migdal effect. Direct detection experiments, crucial for testing the existence of dark matter, encounter formidable obstacles, such as indomitable neutrino backgrounds and elusive determination of dark matter spin. To overcome these challenges, we explore the potential of polarized-target dark matter scattering, examining the impact of nonvanishing mass splitting, and the role of the Migdal effect in detecting dark matter. Our analysis demonstrates the valuable utility of the polarized triple-differential event rate as an effective tool for examining inelastic dark matter. It enables us to investigate angular and energy dependencies, providing valuable insights into the scattering process.