bluuebunny/crossref_metadata_2025 huggingface dataset:
Study the optical properties of Cs3CeI6: First-principles calculations
Authors: Xie Wei , Hu Fuyun , Gong Sha , Peng Liping
Published: January 2024

The band structure, density of states, and optical properties of a novel material, Cs3CeI6 are calculated for the first time using the density functional theory method in first-principles calculations. It is found that Cs3CeI6 possesses a direct bandgap with an energy value of 3.05 eV. Examination of the density of states indicates that the conduction band minimum is primarily composed of Ce-5d and Ce-4f orbitals, while the valence band maximum is mainly contributed by Ce-4f orbitals. Photoluminescence (P.L.) spectroscopy reveals distinctive bimodal emission peaks at 432 and 468 nm, which serve as characteristic signatures of Ce3+ ions. This bimodal emission arises from spontaneous radiative transitions between excited 5d orbitals and the 2F7/2 and 2F5/2 states within the 4f orbital, as confirmed by crystal field calculations. The difference between these two emission peaks corresponds to variations in energy levels associated with Ce3+ ions due to crystal field disturbances. Moreover, Cs3CeI6 exhibits an exciton binding energy of 225 meV due to strong localization effects in Ce-4f orbitals and binding properties inherent in its zero-dimensional structure, promoting exciton formation. Such a substantial exciton binding energy offers significant advantages for potential electroluminescence applications. Based on these findings, we anticipate promising prospects for the use of Cs3CeI6 in electroluminescent devices.
Experimental study of the fast scintillating behavior of ZnO:Ga crystal under MeV electron beam
Authors: Zhang Xiaoding , Jiang Xiaoguo , Li Yiding , Fan Peiliang , He Xiaozhong , Yang Liu
Published: January 2024

An experimental study on the scintillating behavior of ZnO:Ga crystals was conducted using a 7-MeV electron accelerator. The ZnO:Ga crystals were grown using both hydrothermal and chemical vapor transport methods. One of the ZnO:Ga crystals grown via the hydrothermal method exhibited a 1.5-ns afterglow time when excited by an MeV electron beam. The ultra-short scintillation was captured using both an ultrafast streak camera and a framed camera. The experimental results also confirm its potential for diagnosing electron beam trains with a repetition rate of hundreds of MHz.
Field dependence of the electrocaloric effect in BaTiO3 and Ba(Zr0.12Ti0.88)O3: High-resolution measurements around the phase transition
Authors: Fischer J. , Molin C. , Gebhardt S. E. , Hägele D. , Rudolph J.
Published: January 2024

The electric field dependence of the electrocaloric effect is investigated in BaTiO3 and Ba(Zr0.12Ti0.88)O3 by a direct method with sub-mK temperature resolution. The field dependence of the caloric temperature change ΔT(E) shows a pronounced change within a few Kelvin around the Curie temperature for the first-order phase transition in BaTiO3. The transition from a linear field dependence in the ferroelectric phase over a butterfly-shaped to a quadratic field dependence in the paraelectric phase is compared to predictions of Landau–Devonshire theory. The simultaneous measurement of caloric and dielectric properties further allows for the investigation of the polarization dependence ΔT(P) of the electrocaloric effect. We find clear deviations from the predicted quadratic polarization dependence for temperatures close to the Curie temperature. Ba(Zr0.12Ti0.88)O3 shows in contrast only a slow and gradual change of the field dependence over a broad temperature range as a consequence of its diffuse phase transition.
Ferromagnetic resonance-based heat dissipation in dumbbell-like Au–Fe3O4 nanoparticles
Authors: Tonthat Loi , Kuwahata Akihiro , Yabukami Shin
Published: January 2024

Ferromagnetic resonance (FMR) holds promise for heating magnetic nanoparticles (MNPs) in cancer therapy, especially for rapidly heating MNPs. This study aims to enhance the FMR-based heating efficiency of multifunctional hybrid gold and iron oxide nanoparticles (Au-Fe3O4 NPs) as theranostic agents. We experimentally investigate the FMR-based heating properties of newly developed dumbbell-like Au-Fe3O4 NPs, which feature ∼5 nm gold and 15 nm iron oxide components, in comparison to our previously developed Au-coated Fe3O4 NPs (Fe3O4 core ∼5.2 nm, Au shell thickness ∼0.5 nm). For comparison, we also synthesize pure Fe3O4 NPs (∼11 nm) under the same experimental conditions as the dumbbell-like Au-Fe3O4 NPs but without 5 nm Au seeds. Temperature measurements are taken at various DC fields (HDC = 0‒1600 Oe) under a radiofrequency (RF) field (fAC = 4 GHz, HAC = 1.265 Oe) for ∼13s. The results reveal a rapid temperature rise during RF field ON, followed by a decline upon RF field OFF. Remarkably, dumbbell-like Au-Fe3O4 NPs achieve a peak temperature increase of 23.4 °C, corresponding to a heating rate of 1.73 °C/s at HDC = 400 Oe, surpassing the combined values of ∼11 nm Fe3O4 NPs (11.0 °C, i.e., 0.83 °C/s at HDC = 1000 Oe) and ∼5 nm Au NPs (3.5 °C). Comparing these results to our previously developed Au-coated Fe3O4 NPs, which achieved a heating rate of 1.29 °C/s (temperature rise 16.9 °C) under HDC = 1200 Oe with an RF field at fAC = 4 GHz and a significantly higher HAC = 4 Oe (i.e. for HAC = 1.265 Oe, the estimated heating rate was 0.129 °C/s with a temperature rise of 1.69 °C), the dumbbell-shaped Au-Fe3O4 NPs demonstrate a substantially higher temperature increase by 13.4 times. These findings highlight the exceptional potential of dumbbell-shaped Au-Fe3O4 NPs for application in magnetic hyperthermia.
Update of the BIPM comparison BIPM.RI(II)-K1.Cr-51 of activity measurements of the radionuclide 51Cr to include the 2012 result of the KRISS (Rep. of Korea), the 2022 result of the POLATOM (Poland), and to link the 2022 EURAMET.RI(II)-K2.Cr-51 comparison
Authors: Michotte Carine , Courte Sammy , Coulon Romain , Nonis Manuel , Judge Steven , Park Tae Soon , Lee Jong-Man , Lee K B , Ziemek T , Listkowska A , Lech E , Saganowski P , Marganiec-Gałązka J , Broda R
Published: January 2024

Main text

Two new participations in the BIPM.RI(II)-K1.Cr-51 comparison have been added to the previous results and this has produced a revised value for the key comparison reference value (KCRV), calculated using the power-moderated weighted mean. A link has been made to the EURAMET.RI(II)-K2.Cr-51 comparison piloted by the POLATOM in 2022, who sent an ampoule from the EURAMET comparison to the International Reference System (SIR). The LNE-LNHB (France) used the EURAMET comparison to update its degree of equivalence. The degrees of equivalence between each equivalent activity measured in the SIR and the KCRV have been calculated and the results are given in the form of a table for the latest results in the BIPM.RI(II)-K1.Cr-51, and the linked EURAMET.RI(II)-K2.Cr-51. A graphical presentation is also given.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Comparisons of standards for liquid flow rates under static load changes
Authors: Benkova Miroslava , Frahm Enrico , Romieu Kevin , Warnecke Heiko , Büker Oliver , Haack Søren , AKSELLİ Başak , Mazur Viliam , Berkmann Claudia , Zygmantas Gediminas , Kroner Corinna
Published: January 2024

Main text

This report presents the results of an inter-laboratory comparison (ILC) organized in order to determine the degrees of equivalence of standards for liquid static flow rates in the range of 50 kg/h to 36 000 kg/h under ambient pressure and temperature conditions. Water was used as the calibration fluid.

The objective of the comparison was to support and prove the Calibration and Measurement Capabilities (CMC) in liquid flow of the participating NMIs and DIs CETIAT (France), PTB (Germany), FORCE (Denmark), DTI (Denmark), CMI (Czech Republic), RISE (Sweden), VTT (Finland), BEV (Austria), LEI (Lithuania), SMU (Slovakia) and UME TUBITAK (Turkey). The comparison was organized and evaluated by CETIAT, CMI and PTB as pilot laboratories. The comparison was carried out as a three-loop robin, which started in September 2020 at CETIAT and finished in June 2021, also at CETIAT.

Two Coriolis mass flow meters were used as transfer standards. In order to estimate the uncertainties u
TS, both transfer meters were subjected to characterization measurements at pilot laboratory CETIAT. The following parameters were researched in detail: fluid temperature, line pressure, reproducibility and the effect of zero setting. Following the results of the Chi2-test, one set point of one participant was discarded from the E
N calculation.

The comparison shows very good agreement between the 11 participating laboratories. Only one laboratory failed the comparison at two set points due to an E
N value > 1.2. Two laboratories showed comparison results at "warning level". In order to follow the latest developments in the field of flow comparison evaluation, the standard procedure of COX (2002) was extended by an application of two additional criteria, as for inconclusive or conclusive decisions for calibration. In sum, four laboratories were affected by inconclusive calibration results.

The comparison has received financial support from the EMPIR project 17IND13 Metrowamet.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Instability of a Kerr-type naked singularity due to light and matter accretion and its shadow
Authors: Tavlayan Aydin , Tekin Bayram
Published: January 2024

We study null and timelike constant radii geodesics in the environment of an over-spinning putative Kerr-type naked singularity. We are particularly interested in two topics: first, the differences of the shadows of the naked rotating singularity and the Kerr black hole; and second, the spinning down effect of the particles falling from the accretion disk. Around the naked singularity, the non-equatorial prograde orbits in the Kerr black hole remain intact up to a critical rotation parameter (

α
=

6

3

−
9

) and cease to exist above this value (Charbulák and Stuchlík 2018 Eur. Phys. J. C 78 879). This has an important consequence in the shadow of the naked singularity if the shadow is registered by an observer on the polar plane or close to it as the shadow cannot be distinguished from that of a Kerr black hole viewed from the same angle considering only the light emanating from the unstable photon orbits. We show that the timelike retrograde orbits in the equatorial plane immediately (after about an 8% increase in mass for the case of initial α = 1.5) reduce the spin parameter of the naked singularity from larger values to α = 1 at which an event horizon appears. This happens because the retrograde orbits have a larger capture cross-section than the prograde ones. So if a naked singularity happens to have an accretion disk, it will not remain naked for long, an event horizon forms.
A general derivation of the classical Doppler effect in 3D space
Authors: Zanchini Francesco
Published: January 2024

The classical Doppler effect has already been studied in many textbooks and papers. However, the formula currently used to describe the Doppler effect for a source and a receiver moving with constant velocities is not suitable for practical applications. Indeed, the formula makes use of two angles that depend on the state of the source-receiver system both at the emission instant and at the reception instant of sound, while in most real cases the state of the system is known only at one of the two instants. In this paper, two equivalent formulas are derived for the Doppler shift: one depending solely on the state of the system at the emission instant, and one depending solely on the state of the system at the reception instant. The paper also provides two more general expressions that describe the Doppler shift evolution over time. The expressions derived in this paper are compared with the existing ones in some special cases, obtaining consistent results.
A thermoelectric cloud chamber: I. Redesign and operation
Authors: Andrade Antoine F , Souza Lucas W G , Perini Ana P , Neves Lucio P
Published: January 2024

Developed by CTR Wilson, the cloud chamber was among the most important experimental apparatuses for observing nuclear phenomena in the first half of the twentieth century. Currently, cloud chambers are used as a didactic resource to teach radiation-matter interactions and other Nuclear Physics phenomena. This paper presents the construction of an electrically cooled cloud chamber. This device enables the observation of several nuclear physics phenomena in places where dry ice and liquid coolants are unavailable. The apparatus comprises a cooling unit based on thermoelectric modules and high-performance heat sinks. The first tracks are observable within 2 min after the instrument is turned on, and it can continue working for long periods, provided that alcohol is replaced. The device enabled the observation of numerous interactions between ionizing radiation and matter using natural and commercial radiation sources.
A thermoelectric cloud chamber: II. Contributions to medical physics education
Authors: Souza Lucas W G , Perini Ana P , Neves Lucio P
Published: January 2024

Medical Physics is a branch of science concerned with the application of physical principles in the benefit of health. It is an inherently interdisciplinary field that requires strong skills in various fields of science and technology. Thus, it is challenging for students and their learning processes benefit from teaching methodologies that enable a good understanding of abstract concepts. In this context, the cloud chamber can be used as an invaluable tool for teaching concepts related to ionizing radiation. In this study we present the radiation tracks obtained from the cloud chamber presented in Part I of this series. The device enabled the observation of numerous interactions between different ionizing radiations and matter. These interactions are discussed in the context of medical physics, highlighting the connection between the observed phenomena, their physical explanations, and their applications in the medical field.
CUQIpy: II. Computational uncertainty quantification for PDE-based inverse problems in Python
Authors: Alghamdi Amal M A , Riis Nicolai A B , Afkham Babak M , Uribe Felipe , Christensen Silja L , Christian Hansen Per , Jørgensen Jakob S
Published: January 2024

Inverse problems, particularly those governed by Partial Differential Equations (PDEs), are prevalent in various scientific and engineering applications, and uncertainty quantification (UQ) of solutions to these problems is essential for informed decision-making. This second part of a two-paper series builds upon the foundation set by the first part, which introduced CUQIpy, a Python software package for computational UQ in inverse problems using a Bayesian framework. In this paper, we extend CUQIpy’s capabilities to solve PDE-based Bayesian inverse problems through a general framework that allows the integration of PDEs in CUQIpy, whether expressed natively or using third-party libraries such as FEniCS. CUQIpy offers concise syntax that closely matches mathematical expressions, streamlining the modeling process and enhancing the user experience. The versatility and applicability of CUQIpy to PDE-based Bayesian inverse problems are demonstrated on examples covering parabolic, elliptic and hyperbolic PDEs. This includes problems involving the heat and Poisson equations and application case studies in electrical impedance tomography and photo-acoustic tomography, showcasing the software’s efficiency, consistency, and intuitive interface. This comprehensive approach to UQ in PDE-based inverse problems provides accessibility for non-experts and advanced features for experts.
Imaging of nonlinear materials via the Monotonicity Principle
Authors: Mottola Vincenzo , Corbo Esposito Antonio , Piscitelli Gianpaolo , Tamburrino Antonello
Published: January 2024

Inverse problems, which are related to Maxwell’s equations, in the presence of nonlinear materials is a quite new topic in the literature. The lack of contributions in this area can be ascribed to the significant challenges that such problems pose. Retrieving the spatial behavior of some unknown physical property, from boundary measurements, is a nonlinear and highly ill-posed problem even in the presence of linear materials. Furthermore, this complexity grows exponentially in the presence of nonlinear materials. In the tomography of linear materials, the Monotonicity Principle (MP) is the foundation of a class of non-iterative algorithms able to guarantee excellent performances and compatibility with real-time applications. Recently, the MP has been extended to nonlinear materials under very general assumptions. Starting from the theoretical background for this extension, we develop a first real-time inversion method for the inverse obstacle problem in the presence of nonlinear materials. The proposed method is intendend for all problems governed by the quasilinear Laplace equation, i.e. static problems involving nonlinear materials. In this paper, we provide some preliminary results which give the foundation of our method and some extended numerical examples.
Detection of type-Ⅱ diabetes using graphene-based biosensors
Authors: Roondhe Basant , Saha Sankhadip , Luo Wei , Ahuja Rajeev , Saxena Sumit
Published: January 2024

Diabetes is a global pandemic that increases the risk of various health complications, including heart attacks, renal failure, blindness, stroke, and peripheral neuropathy. Type-2 diabetes (T2D) results from an imbalance in lipid and glucose metabolism due to hostility to insulin action and insufficient insulin production response. Valine amino acid has been identified as a potential biomarker for T2D, but there have been no rigorous studies on its interaction with branch chain amino acids. In this study, we investigated the potential of graphene/modified graphene as a valine biosensor using density functional theory to examine the electronic properties and adsorption behaviour of graphene, Si-doped graphene (SiG), and P-doped graphene (PG). The adsorption of valine over the substrates was physisorption in nature, and the adsorption energies were in the order of SiG > G > PG. Density of states (DOS) and partial DOS calculations confirmed the molecule’s adsorption over the monolayers and indicated variations in the electronic properties. We also performed recovery time calculations to examine the reusability of the nano-surfaces as potential biosensors. Ultrafast recovery times were predicted for all three systems, with SiG showing the best results. Our study suggests that SiG could be used as a biosensor for valine, providing a real-time and efficient diagnostic tool for T2D.
Depolarization of metal surfaces based on Mueller and integral equation method
Authors: Li Yanhui , Yang Pengfei , Zhao Hua , Bai Lu , Luo Yi
Published: January 2024

This paper delves into the depolarization phenomenon of materials using the integral equation method and Mueller matrix method. In the integral equation method, it is observed that depolarization trends with roughness are similar at different wavelengths, but numerical differences exist. The results are well-supported by both theory and experiments. Specifically, at 1064 nm wavelength, materials exhibit smaller depolarization peaks, smoother trends, and right-shifted peaks compared to 633 nm. Additionally, the polarization characteristics of materials may change with varying incident polarization states. The Mueller matrix method investigates the depolarization trend with varying incident angles and different roughness levels. It reveals a gradual increase in depolarization with the incident angle until 60°, followed by a rapid rise, reaching a peak around 80°. Moreover, materials with higher absorption coefficients exhibit stronger depolarization effects. Overall, this research uncovers the impact of absorption and scattering on the polarization properties of materials, providing valuable insights for future studies in polarization recognition.
Characterization of wireless power transfer based on Fano resonant-like surface
Authors: Wei Yihao , Chen Lina , Chen Yongqiang , Liu Yanhong , Deng Fusheng , Su Xiaoqiang , Dong Lijuan
Published: January 2024

This paper presents a new way to enhance the transmission efficiency of a dual-coils wireless power transfer system. That method is to introduce a Fano resonant-like surface in the dual-coils wireless power transfer system. This surface, positioned opposite the transmission direction of the transmitter coil in the system, adopts a four-armed helical structure. The results demonstrate that introducing the Fano resonant-like surface significantly enhances system transmission efficiency, attributed to two primary factors. First, the Fano local resonance effect in the dual-coils wireless power transfer system with Fano resonant-like surface leads to the enhance the transmission efficiency. Second, the Fano resonant-like surface shields the energy propagation of the nearby magnetic field in the direction opposite to transmission. Further, compared to a wireless power transfer system comprising only two coils, the overall improvement in transmission efficiency is 30%–40%. Owing to its simplicity, more compact size, cost-effectiveness, and ease of integration without having to be placed between the transmitting and receiving coils, the Fano resonant-like surface can lay the groundwork for practical applications in wireless charging.
Leakage mechanisms of sub-pA InGaAs/GaAs nano-ridge waveguide photodetectors monolithically integrated on a 300-mm Si wafer
Authors: Ozdemir Cenk Ibrahim , Koninck Yannick De , Patra Saroj Kanta , Baryshnikova Marina , Kunert Bernardette , Pantouvaki Marianna , Campenhout Joris Van , Van Thourhout Dries
Published: January 2024

We report on a comprehensive temperature dependent dark current study of high-quality InGaAs/GaAs multi quantum well waveguide photodetectors monolithically integrated on silicon. They are integrated through metalorganic vapor-phase selective-area epitaxial growth in a 300 mm CMOS pilot line. Defects resulting from the metamorphic growth of III-V devices on Si make these devices susceptible to different leakage mechanisms at higher operating temperatures. For the high-temperature operation of complex photonics-electronics integrations, understanding the leakage mechanisms of the devices has critical significance. This will help to optimize designs promptly and ensure the reliability and longevity of such devices under extreme operating conditions. The photodetector devices exhibit dark currents below 1 pA, at room temperature and −1 V bias voltage, limited by the noise floor of the measurement setup. To resolve the different leakage mechanisms contributing to the dark current, the devices were measured at elevated temperatures and the results were cross-validated with device simulations. The devices exhibited very low dark currents, with a median below 0.1 nA at 195 °C, suggesting very high-quality material growth. Through device models, leakage mechanisms related to Shockley-Read-Hall (SRH) recombination at bulk volume defects are found to be the main factor contributing to the dark current. The surface SRH recombination is found to be limited, yet affecting the forward bias dark current due to the shortening of the diffusion paths of the majority carriers. Also, the device model shows that the actual dark currents at room temperature can be as low as 0.01 pA, more than 1-order lower than the measured levels. This study emphasizes the high quality of the III-V nano-ridge waveguide devices grown on Si, which can potentially expand the capabilities of silicon photonics platforms further.
Lorentz violation in γ-pair production (e+e−→ γ γ)
Authors: Celeste Alessio T B , Santos Adriano M
Published: January 2024

In this paper, we investigate the production process of a photon pair in a regime of quantum electrodynamics, considering the presence of a constant four-vector that defines a privileged direction in spacetime, resulting in Lorentz symmetry violation. We explore Lorentz violation in the context of vectorial nonminimal coupling, where we analyze the modifications introduced by this coupling in the scattering amplitude at the vertex. Moreover, we delve into Lorentz violation with axial-like nonminimal coupling. Both analyses are conducted by examining the constant four-vector of both time-like and space-like types.
An entropy trap model of thermodynamic anomalies for dual-amorphous water undergoing liquid-liquid phase transition
Authors: Li Peizhao , Lu Haibao
Published: January 2024

Water displays numerous anomalously thermodynamic behaviors. However, the working principles behind these anomalies are not well understood, and the liquid-liquid phase transition (LLPT) is often regarded as the potential reason. In this study, we developed an entropy trap model to characterize the thermodynamic LLPT in dual-amorphous water, i.e. having both low-density and high-density liquid water. From the Adam-Gibbs model and free-volume theory, thermodynamic behaviors of water have been described using the proposed model, in which the constitutive relationships among density, heat capacity, thermal expansivity and glass transition temperature have been formulated. Moreover, the glass transition and its connection to thermodynamic behaviors were also investigated for dual-amorphous water. Finally, experimental data reported in the literature were used to verify effectiveness of the proposed model. This study is expected to provide a physical insight into the anomalous thermodynamics of dual-amorphous water undergoing the LLPT.
Transfer learning from Hermitian to non-Hermitian quantum many-body physics
Authors: Sayyad Sharareh , Lado Jose L
Published: January 2024

Identifying phase boundaries of interacting systems is one of the key steps to understanding quantum many-body models. The development of various numerical and analytical methods has allowed exploring the phase diagrams of many Hermitian interacting systems. However, numerical challenges and scarcity of analytical solutions hinder obtaining phase boundaries in non-Hermitian many-body models. Recent machine learning methods have emerged as a potential strategy to learn phase boundaries from various observables without having access to the full many-body wavefunction. Here, we show that a machine learning methodology trained solely on Hermitian correlation functions allows identifying phase boundaries of non-Hermitian interacting models. These results demonstrate that Hermitian machine learning algorithms can be redeployed to non-Hermitian models without requiring further training to reveal non-Hermitian phase diagrams. Our findings establish transfer learning as a versatile strategy to leverage Hermitian physics to machine learning non-Hermitian phenomena.
Predicted multiple charge density wave phases in monolayer 1T-NbO2
Authors: Li Yi-Chi , Zhou Jian
Published: January 2024

Layered transition-metal dichalcogenides, such as NbSe2, have been extensively studied for almost half a century due to their intriguing properties, such as charge density wave (CDW) and superconductivity. Can the layered transition-metal dioxide, such as NbO2, be stable and exhibit CDW, given that it has the same crystal structure and electronic configuration as NbSe2? Here, we use first-principles calculations to predict that 1T-NbO2 is possibly stable at high temperatures, but it would undergo two CDW transitions with

12

×

12

and

13

×

13

periodicities at low temperatures. Both CDW transitions are accompanied by a metal-semiconductor transition. Notably, the

13

×

13

CDW phase of NbO2 possesses localized magnetic moments and hosts a Mott insulating state. This work offers a fresh outlook on studying CDW and Mott transition in low-dimensional oxide materials.
Spin-photon interaction in a nanowire quantum dot with asymmetrical confining potential
Authors: Li Rui
Published: January 2024

The electron (hole) spin–photon interaction is studied in an asymmetrical InSb (Ge) nanowire quantum dot. The spin–orbit coupling in the quantum dot mediates not only a transverse spin–photon interaction, but also a longitudinal spin–photon interaction due to the asymmetry of the confining potential. Both the transverse and the longitudinal spin–photon interactions have non-monotonic dependence on the spin–orbit coupling. For realistic spin–orbit coupling in the quantum dot, the longitudinal spin–photon interaction is much (at least one order) smaller than the transverse spin–photon interaction. The order of the transverse spin–photon interaction is about 1 nm in terms of length

|

z

e
g

|

, or 0.1 MHz in terms of frequency

e

E

0

|

z

e
g

|

/

h

for a moderate cavity electric field strength

E

0

=
0.4

V m−1.
Low-loss millimeter-wave resonators with an improved coupling structure
Authors: Anferov A , Harvey S P , Wan F , Lee K H , Simon J , Schuster D I
Published: January 2024

Millimeter-wave superconducting resonators are a useful tool for studying quantum device coherence in a new frequency domain. However, improving resonators is difficult without a robust and reliable method for coupling millimeter-wave signals to 2D structures. We develop and characterize a tapered transition structure coupling a rectangular waveguide to a planar slotline waveguide with better than 0.5 dB efficiency over 14 GHz, and use it to measure ground-shielded resonators in the W band (75–110 GHz). Having decoupled the resonators from radiative losses, we consistently achieve single-photon quality factors above 105, with a two-level-system loss limit above 106, and verify the effectiveness of oxide removal treatments to reduce loss. These values are 4–5 times higher than those previously reported in the W band, and much closer to typical planar microwave resonators. The improved losses demonstrated by these on-chip millimeter-wave devices shed new light on quantum decoherence in a different frequency regime, offer increased selectivity for high-frequency detectors, and enables new possibilities for hybrid quantum experiments integrating millimeter-wave frequencies.
Exponential relaxation of the energy and desorption dynamics of atoms colliding with a surface
Authors: Zeng Dandan , Jiang Jianzheng , Liu Chong , Fan Jing
Published: January 2024

Atom–surface collisions are one of the most important topics in surface science. To further disclose the physical mechanism underlying atom–surface interaction at the microscopic level, we study the dynamics of an incident atom with a molecular dynamics simulation. Emphasis is put on the temporal evolutions of energy and residence times of the colliding atoms. The incident atoms experience two stages after colliding with the surface. First, the atoms relax to the equilibrium state in an exponential fashion. Then, the atoms become equilibrated with the surface and depart from the surface with a converged desorption rate. Two parameters are proposed to characterize the process: the characteristic energy relaxation time and the equilibrium residence time. At the relaxation stage, the desorption rate varies with the energy, and the probability distribution function (PDF) of the residence time obeys a power law. At the equilibrium state, the desorption rate is invariable, and the PDF of the residence time decays exponentially. We further find that the desorption rate for both stages can be calculated by a consistent Arrhenius equation, with the desorption activation energy and kinetic energy evolving with time in the relaxation stage. It appears that the gas–surface interaction dynamics can be explained by trapping-desorption theory in both the relaxation state and the equilibration state.
Accretion flow in deformed Kerr spacetime: spectral energy distributions from free-free emission
Authors: Patra Subhankar , Majhi Bibhas Ranjan , Das Santabrata
Published: January 2024

In this paper, we study the properties of accretion flow including its spectral features in Johannsen and Psaltis (JP) non-Kerr spacetime. In doing so, we numerically solve the governing equations that describe the flow motion around the compact objects in a general relativistic framework, where spin (ak
) and deformation parameters (ε) demonstrate the nature of the central source, namely black hole (BH) or naked singularity (NS). With this, we obtain all possible classes of global accretion solutions (i.e., O, A, W and I-type) by varying the energy (E) and angular momentum (λ) of the relativistic accretion flow, and examine the role of thermal bremsstrahlung emission in studying the spectral energy distributions (SEDs) of the accretion disc. We divide the parameter space in λ-E plane in terms of the different classes of accretion solutions for BH and NS models. We further calculate the disc luminosity (L) corresponding to these accretion solutions, and observe that I-type solutions yield higher L and SEDs than the remaining types of solutions for both BH and NS models. For BH model, SEDs for W and I-type solutions differ significantly from the results for O and A-type solutions for low E values. On the contrary, for NS model, SEDs for different accretion solutions are identical in the whole parameter space of λ and E. We also examine the effect of ε on the SEDs and observe that a non-Kerr BH yields higher SEDs than the usual Kerr BH. Finally, for accretion solutions of identical E and λ, we compare the SEDs obtained from BH and NS models, and find that naked singularity objects produce more luminous power spectra than the black holes.
Building and characterizing a stylus ion-trap system
Authors: Cui 崔 Tai-Hao 太豪 , Wei 魏 Ya-Qi 雅琪 , Li 李 Ji 冀 , Yuan 袁 Quan 泉 , Dai 戴 Shuang-Qing 双晴 , Li 李 Pei-Dong 沛东 , Zhou 周 Fei 飞 , Zhang 张 Jian-Qi 建奇 , Zheng 郑 Zhu-Jun 驻军 , Chen 陈 Liang 亮 , Feng 冯 Mang 芒
Published: January 2024

Cold trapped ions can be excellent sensors for ultra-precision detection of physical quantities, which strongly depends on the measurement situation at hand. The stylus ion trap, formed by two concentric cylinders over a ground plane, holds the promise of relatively simple structure and larger solid angle for optical access and fluorescence collection in comparison with the conventional ion traps. Here we report our fabrication and characterization of the first stylus ion trap constructed in China, aiming for studying quantum optics and sensing weak electric fields in the future. We have observed the stable confinement of the ion in the trapping potential for more than two hours and measured the heating rate of the trap to be dε/dt = 7.10 ± 0.13 meV/s by the Doppler recooling method. Our work starts a way to building practical quantum sensors with high efficiency of optical collection and with ultimate goal for contributing to future quantum information technology.
Electron beam analysis and sensitivity studies for the EuPRAXIA@SPARC_LAB RF injector
Authors: Giribono A , Alesini D , Bacci A , Bellaveglia M , Cardelli F , Chiadroni E , Del Dotto A , Faillace L , Ferrario M , Gallo A , Ghigo A , Giannetti G , Mostacci A , Opromolla M , Petrillo V , Piersanti L , Pompili R , Romeo S , Rossetti Conti M , Rossi A R , Shpakov V , Silvi G J , Vaccarezza C
Published: January 2024

The interest in plasma-based accelerators as drivers of user facilities is growing worldwide thanks to their compactness and reduced costs. The EuPRAXIA@SPARC_LAB collaboration is preparing a technical design report for a multi-GeV plasma-based accelerator with outstanding electron beam quality to pilot an X-ray FEL, the most demanding in terms of beam brightness. The beam dynamics has been studied aiming to a reliable operation of the RF injector to generate a so-called comb-beam with 500 MeV energy suitable as driver of the Beam-driven Plasma Wakefield Accelerator. A case of interest is the generation of a trailing bunch with 1 GeV energy, less than 1 mm-mrad transverse emittance and up to 2 kA peak current at the undulator entrance. The comb-beam is generated through the velocity bunching technique, an RF compression tool that enables high brightness beams within relatively compact machine. Since it is based on a rotation of the beam phase space inside the external RF fields, it could be particularly sensitive to amplitude and phase jitters in the RF injector. The electron beam dynamics and the machine sensitivity to the possible jitters are presented in terms of effect on the beam quality so to provide the basis for the jitter tolerances.
Hydrodynamic Model for Particle Beam-Driven Wakefield in Carbon Nanotubes
Authors: Martín-Luna P , Apsimon O , Barberá-Ramos M , Bonatto A , Bontoiu C , Xia G , Resta-López J
Published: January 2024

The charged particles moving through a carbon nanotube (CNT) may be used to excite electromagnetic modes in the electron gas produced in the cylindrical graphene shell that makes up a nanotube wall. This effect has recently been proposed as a potential novel method of short-wavelength-high-gradient particle acceleration. In this contribution, the existing theory based on a linearized hydrodynamic model for a localized point-charge propagating in a single wall nanotube (SWNT) is reviewed. In this model, the electron gas is treated as a plasma with additional contributions to the fluid momentum equation from specific solid-state properties of the gas. The governing set of differential equations is formed by the continuity and momentum equations for the involved species. These equations are then coupled by Maxwell’s equations. The differential equation system is solved applying a modified Fourier-Bessel transform. An analysis has been realized to determine the plasma modes able to excite a longitudinal electrical wakefield component in the SWNT to accelerate test charges. Numerical results are obtained showing the influence of the damping factor, the velocity of the driver, the nanotube radius, and the particle position on the excited wakefields. A discussion is presented on the suitability and possible limitations of using this method for modelling CNT-based particle acceleration.
High Intensity Beam Operation of J-PARC RCS With Minimum Beam Loss
Authors: Saha P.K. , Harada H. , Shobuda Y. , Tamura F. , Okita H. , Okabe K. , Nakanoya T. , Hatakeyama S. , Moriya K. , Takayanagi T. , Hotchi H.
Published: January 2024

The 3-GeV RCS (Rapid Cycling Synchrotron) of J-PARC (Japan Proton Accelerator Research Complex) at present operates at a high intensity beam near to 1 MW beam power. The beam loss and the corresponding residual radiation are key issues for beam intensity ramp up. Based on detail numerical simulations and systematic beam studies the beam loss has been well mitigated to a minimum level. The residual beam loss at 1 MW beam power is mostly due to unavoidable foil scattering of the circulating beam during injection. We have identified almost all major beam loss sources and optimized to minimize the beam loss for achieving a stable operation at 800 kW beam power since April 2022.
Determination of the Invariant Spin Axis in a COSY model using Bmad
Authors: Vitz M , Lehrach A , Pretz J
Published: January 2024

The matter-antimatter asymmetry might be understood by investigating the EDM (Electric Dipole Moment) of elementary particles. A permanent EDM of a subatomic particle violates time reversal and parity symmetry at the same time and would be, with the currently achievable experimental accuracy, an indication for further CP violation than established in the SM (Standard Model of Particle Physics). The JEDI-Collaboration (Jülich Electric Dipole moment Investigations) in Jülich has performed a direct EDM measurement for deuterons with the so-called precursor experiments at the storage ring COSY (COoler SYnchrotron) by measuring the orientation of the ISA (Invariant Spin Axis). In order to interpret the measured data and to disentangle a potential EDM signal from systematic effects, spin tracking simulations in an accurate simulation model of COSY are needed. Therefore a model of COSY was implemented using the software library Bmad. Systematic effects were considered by including element misalignments, effective dipole shortening, longitudinal fields and steerer kicks. These effects rotate the ISA in addition to the EDM and have to be analyzed and understood. The most recent spin tracking results as well as the methods to find the ISA are presented in this paper.
Metallic Neutral Vapours Diffusion in Electron Cyclotron Resonance Ion Sources: Fluid Dynamics and Particle Tracing Simulations
Authors: Pidatella A , Galatà A , Maimone F , Mishra B , Naselli E , Celona L , Lang R , Mauro G S , Santonocito D , Torrisi G , Mascali D
Published: January 2024

Resistive oven technique is used to inject vapours of metallic species in electron cyclotron resonance (ECR) plasma traps, where plasma provides step-wise ionization of neutral metals, producing charged ion beams for accelerators. We present a numerical survey of metallic species suitable for oven injection in ECR ion sources, studying neutrals diffusion and deposition under molecular flow regime. These aspects depend on geometry of the evaporation inlet, thermodynamics, and plasma parameters, which strongly impact on ionization and charge-exchange rate, thus on the fraction of reacting neutrals. We considered diffusion of metals with and without plasma. The plasma and its parameters have been modelled considering an established self-consistent particle-in-cell model. Numerical predictions might be relevant to reduce the metal consumption, to increase the overall efficiency, and to improve the plasma ion source performances. As test case, we studied the 134Cs isotope, as one of the alkali metals of interest for the modern nuclear physics.
Suppression of Microbunching Instability based on optimized velocity bunching in linac-driven FELs
Authors: Cheng Wencai , Zhu Zihan , Zhao Minghua , Zhang Meng , Gu Duan
Published: January 2024

The microbunching instability (MBI) driven by beam collective effects can cause significant electron beam quality degradation in advanced x-ray free electron lasers. Typically, multiple stage magnetic bunch compressors used to generate high peak current electron beam will dramatically amplify the microbunching instability. In this paper, by redesigning the solenoid elaborately and adopting a dual-mode buncher cavity with the third harmonic mode used to correct the RF curvature, it is potential for the electron beam to be further compressed in velocity bunching (VB) process. Therefore, a VB plus one bunch compressor could be a promising alternative scheme to achieve moderate peak current beam for high-repetition-rate X-ray FELs to suppress the additional MBI gain due to multi-stage magnetic bunch compressors.
Study of beam-beam interaction in FCC-ee including updated transverse and longitudinal Impedances
Authors: Zhang Y. , Migliorati M. , Zobov M.
Published: January 2024

Beam-beam interaction in FCC-ee can be seriously affected by the vacuum chamber coupling impedance resulting in a safe tune areas reduction, tune shifts and spread, bunch length and energy spread variation. The interplay of the two effects has a drastic impact on the stability of colliding bunches and respectively on the achievable luminosity. In this paper, beam-beam collisions in FCC-ee with 4 interaction points are studied including the updated transverse and longitudinal impedances.
PLACET3: 6D tracking through PETS and accelerating structures wakefields
Authors: Costa Raul , Latina Andrea , Olvegård Maja
Published: January 2024

We present the latest updates to the PLACET3 tracking package, which focus on the impact of both transverse and longitudinal wakefields on a beam travelling through accelerating and decelerating structures. The main focus of this update was the first implementation of 6D tracking through Power Extraction and Transfer Structures (PETS) for the Compact Linear Collider (CLIC), which is described through short and long-range longitudinal wakefields. Additionally, we present the impact of different numerical schemes on the computation of wakefields in accelerating structures.
Macroparticle Collisionality in PIC solver
Authors: Engeda A , Franchetti G
Published: January 2024

This paper presents a new numerical technique for the calculation of the Coulomb interaction between nearby charged particles. The efficiency of this method is demonstrated by distributing charged particles in a three dimensional sphere for an amount of particles, Npar
, ranging from 1 × 105 to 1.6 × 106. Using the presented method, the computation of the mean field and Coulomb near field interaction can be performed separately.
Machine learning-based optimization of storage ring injection efficiency
Authors: Schirmer D , Althaus A , Hüser S , Khan S , Schüngel T
Published: January 2024

Since the DELTA accelerator facility does not use a White circuit-driven fast topping-up mode, each software-driven injection ramp cycle takes about 7 seconds. Depending on the injection efficiency, 150 to 200 ramp cycles are required to reach the maximum beam current of 130 mA in the storage ring. Thus, for fast post-injection, a high electron transfer rate is crucial. During the injection process, a large number of parameters (e. g., magnet settings, timings of pulsed elements) have to be adjusted manually. The injection efficiency depends mainly on the settings of the booster extraction elements, the T2 transfer line magnets, and the storage ring injection components. In order to automate the injection procedure and to improve the electron transfer efficiency, the application of innovative machine learning concepts was studied.
Commissioning of X-LAB: a very high-capacity X-band RF test stand facility at the University of Melbourne
Authors: Volpi Matteo , Giansiracusa P. J. , Sheehy S. L. , Williams S. D. , Rassool R. P. , Taylor G. , Pushkarna P. , Dowd R. T. , Zingre K. , Boronat M. , Catalan-Lasheras N. , McMonagle G.
Published: January 2024

The Compact Linear Collider (CLIC) beam-based acceleration baseline uses high-gradient travelling wave accelerating structures at a frequency of 12 GHz. In order to prove the performance of these structures at high peak power and short pulse width RF, two klystron-based test facilities will be put in operation this year. The first Southern Hemisphere X-band Laboratory for Accelerators and Beams (X-LAB) is currently being commissioned at the University of Melbourne, it will house half of the CERN X-band test stand XBOX3, which has been renamed Mel-BOX. Like XBOX3, Mel-BOX employs a novel means of combining high average power but relatively low peak power (6 MW) klystron units to direct power to two testing slots with a repetition rate of up to 400 Hz. As well as the repetition rate, peak power, pulse length and pulse shape can be customised to fit the testing requirements. This novel means of producing high power and high repetition RF pulses can eventually be used for many other applications where multiple test slots are required. This proceedings focuses on the integration and 1st commissioning of Mel-BOX with short pulses. There are also plans for it to form the basis for developing a compact accelerator for medical or university applications, such as radiotherapy and compact light sources [1].