arXiv subjects

J. Zhang

Publications and source records attributed to J. Zhang.

At least 91 records · Page 5Linked to original sources

arXiv2023

The Multiview Observatory for Solar Terrestrial Science (MOST)

We report on a study of the Multiview Observatory for Solar Terrestrial Science (MOST) mission that will provide comprehensive imagery and time series data needed to understand the magnetic connection between the solar interior and the solar atmosphere/inner heliosphere. MOST will build upon the successes of SOHO and STEREO missions with new views of the Sun and enhanced instrument capabilities. This article is based on a study conducted at NASA Goddard Space Flight Center that determined the required instrument refinement, spacecraft accommodation, launch configuration, and flight dynamics for mission success. MOST is envisioned as the next generation great observatory positioned to obtain three-dimensional information of large-scale heliospheric structures such as coronal mass ejections, stream interaction regions, and the solar wind itself. The MOST mission consists of 2 pairs of spacecraft located in the vicinity of Sun-Earth Lagrange points L4 (MOST1, MOST3) and L5 (MOST2 and MOST4). The spacecraft stationed at L4 (MOST1) and L5 (MOST2) will each carry seven remote-sensing and three in-situ instrument suites, including a novel radio package known as the Faraday Effect Tracker of Coronal and Heliospheric structures (FETCH). MOST3 and MOST4 will carry only the FETCH instruments and are positioned at variable locations along the Earth orbit up to 20° ahead of L4 and 20° behind L5, respectively. FETCH will have polarized radio transmitters and receivers on all four spacecraft to measure the magnetic content of solar wind structures propagating from the Sun to Earth using the Faraday rotation technique. The MOST mission will be able to sample the magnetized plasma throughout the Sun-Earth connected space during the mission lifetime over a solar cycle.

astro-ph.SR↗

arXiv2023

NvDEx-100 Conceptual Design Report

Observing nuclear neutrinoless double beta (0vbb) decay would be a revolutionary result in particle physics. Observing such a decay would prove that the neutrinos are their own antiparticles, help to study the absolute mass of neutrinos, explore the origin of their mass, and may explain the matter-antimatter asymmetry in our universe by lepton number violation. We propose developing a time projection chamber (TPC) using high-pressure 82SeF6 gas and top-metal silicon sensors for read-out in the China Jinping Underground Laboratory (CJPL) to search for neutrinoless double beta decay of 82Se, called the NvDEx experiment. Besides being located at CJPL with the world's thickest rock shielding, NvDEx combines the advantages of the high Qbb (2.996 MeV) of 82Se and the TPC's ability to distinguish signal and background events using their different topological characteristics. This makes NvDEx unique, with great potential for low-background and high-sensitivity 0vbb searches. NvDEx-100, a NvDEx experiment phase with 100 kg of SeF6 gas, is being built, with plans to complete installation at CJPL by 2025. This report introduces 0vbb physics, the NvDEx concept and its advantages, and the schematic design of NvDEx-100, its subsystems, and background and sensitivity estimation.

physics.ins-det↗

arXiv2023

Kinetic-Scale Topological Structures Associated with Energy Dissipation in the Turbulent Reconnection Outflow

Assisted with Magnetospheric Multiscale (MMS) mission capturing unprecedented high-resolution data in the terrestrial magnetotail, we apply a local streamline-topology classification methodology to investigate the categorization of the magnetic-field topological structures at kinetic scales in the turbulent reconnection outflow. It is found that strong correlations between the straining and rotational part of the velocity gradient tensor as well as the magnetic-field gradient tensor. The strong energy dissipation prefers to occur at regions with high magnetic stress or current density, which is contributed mainly by O-type topologies. These results indicate that the kinetic structures with O-type topology play more import role in energy dissipation in turbulent reconnection outflow.

physics.plasm-ph↗

arXiv2023

Modeling and characterization of TES-based detectors for the Ricochet experiment

Coherent elastic neutrino-nucleus scattering (CE$ν$NS) offers a valuable approach in searching for physics beyond the Standard Model. The Ricochet experiment aims to perform a precision measurement of the CE$ν$NS spectrum at the Institut Laue-Langevin nuclear reactor with cryogenic solid-state detectors. The experiment plans to employ an array of cryogenic thermal detectors, each with a mass around 30 g and an energy threshold of sub-100 eV. The array includes nine detectors read out by Transition-Edge Sensors (TES). These TES based detectors will also serve as demonstrators for future neutrino experiments with thousands of detectors. In this article we present an update in the characterization and modeling of a prototype TES detector.

hep-ex↗

arXiv2023

Wind-wave growth over a viscous liquid

Experimental and theoretical studies on wind-wave generation have focused primarily on the air-water interface, where viscous effects are small. Here we characterize the influence of the liquid viscosity on the growth of mechanically generated waves. In our experiment, wind is blowing over a layer of silicon oil, of viscosity 20 and 50 times that of water, and waves of small amplitude are excited by an immersed wave-maker. We measure the spatial evolution of the wave slope envelope using Free-Surface Synthetic Schlieren, a refraction-based optical method. Through spatiotemporal band-pass filtering of the surface slope, we selectively determine the spatial growth rate for each forcing frequency, even when the forced wave is damped and coexists with naturally amplified waves at other frequencies. Systematic measurements of the growth rate for various wind velocities and wave frequencies are obtained, enabling precise determination of the marginal stability curve and the onset of wave growth. We show that Miles' model, which is commonly applied to water waves, offers a reasonable description of the growth rate for more viscous liquids. We finally discuss the scaling of the growth rate of the most amplified wave and the critical friction velocity with the liquid viscosity.

physics.flu-dyn↗

arXiv2023

Constraints on the onset of color transparency from quasi-elastic $^{12}$C$(e,e'p)$ up to $Q^2=\,14.2\,$(GeV$/c)^2$

Quasi-elastic scattering on $^{12}$C$(e,e'p)$ was measured in Hall C at Jefferson Lab for space-like 4-momentum transfer squared $Q^2$ in the range of 8--14.2\,(GeV/$c$)$^2$ with proton momenta up to 8.3\,GeV/$c$. The experiment was carried out in the upgraded Hall C at Jefferson Lab. It used the existing high momentum spectrometer and the new super high momentum spectrometer to detect the scattered electrons and protons in coincidence. The nuclear transparency was extracted as the ratio of the measured yield to the yield calculated in the plane wave impulse approximation. Additionally, the transparency of the $1s_{1/2}$ and $1p_{3/2}$ shell protons in $^{12}$C was extracted, and the asymmetry of the missing momentum distribution was examined for hints of the quantum chromodynamics prediction of Color Transparency. All of these results were found to be consistent with traditional nuclear physics and inconsistent with the onset of Color Transparency.

nucl-ex↗

arXiv2023

Colliding of two high Mach-number quantum degenerate plasma jets

Colliding of two high Mach-number quantum degenerate plasmas is one of the most essential components in the double-cone ignition (DCI) inertial confinement fusion scheme, in which two highly compressed plasma jets from the cone-tips collide along with rapid conversion from the colliding kinetic energies to the internal energy of a stagnated isochoric plasma. Due to the effects of high densities and high Mach-numbers of the colliding plasma jets, quantum degeneracy and kinetic physics might play important roles and challenge the predictions of traditional hydrodynamic models. In this work, the colliding process of two high Mach number quantum degenerate Deuterium-plasma jets with sizable scale ($\sim 1000\ \si{μm}$, $\sim 300\ \si{ps}$, $\sim 100\ \si{g/cc}$, $\sim 300\ \si{km/s}$) were investigated with first-principle kinetic simulations and theoretical analyses. In order to achieve high-density compression, the colliding kinetic pressure should be significantly higher than the pressure raised by the quantum degeneracy. This means high colliding Mach numbers are required. However, when the Mach number is further increased, we surprisingly found a decreasing trend of density compression, due to kinetic effects. It is therefore suggested that there is theoretically optimal colliding velocity to achieve the highest density compression. Our results would provide valuable suggestions for the base-line design of the DCI experiments and also might be of relevance in some violent astrophysical processes, such as the merger of two white dwarfs.

physics.plasm-ph↗

arXiv2023

First Measurement of the EMC Effect in $^{10}$B and $^{11}$B

The nuclear dependence of the inclusive inelastic electron scattering cross section (the EMC effect) has been measured for the first time in $^{10}$B and $^{11}$B. Previous measurements of the EMC effect in $A \leq 12$ nuclei showed an unexpected nuclear dependence; $^{10}$B and $^{11}$B were measured to explore the EMC effect in this region in more detail. Results are presented for $^9$Be, $^{10}$B, $^{11}$B, and $^{12}$C at an incident beam energy of 10.6~GeV. The EMC effect in the boron isotopes was found to be similar to that for $^9$Be and $^{12}$C, yielding almost no nuclear dependence in the EMC effect in the range $A=4-12$. This represents important, new data supporting the hypothesis that the EMC effect depends primarily on the local nuclear environment due to the cluster structure of these nuclei.

nucl-ex↗

arXiv2023

Detector R&D needs for the next generation $e^+e^-$ collider

The 2021 Snowmass Energy Frontier panel wrote in its final report "The realization of a Higgs factory will require an immediate, vigorous and targeted detector R&D program". Both linear and circular $e^+e^-$ collider efforts have developed a conceptual design for their detectors and are aggressively pursuing a path to formalize these detector concepts. The U.S. has world-class expertise in particle detectors, and is eager to play a leading role in the next generation $e^+e^-$ collider, currently slated to become operational in the 2040s. It is urgent that the U.S. organize its efforts to provide leadership and make significant contributions in detector R&D. These investments are necessary to build and retain the U.S. expertise in detector R&D and future projects, enable significant contributions during the construction phase and maintain its leadership in the Energy Frontier regardless of the choice of the collider project. In this document, we discuss areas where the U.S. can and must play a leading role in the conceptual design and R&D for detectors for $e^+e^-$ colliders.

hep-ex↗

arXiv2023

Superconductivity Observed in Tantalum Polyhydride at High Pressure

We report experimental discovery of tantalum polyhydride superconductor. It was synthesized at high pressure and high temperature conditions using diamond anvil cell combined with in-situ high pressure laser heating techniques. The superconductivity was investigated via resistance measurements at pressures. The highest superconducting transition temperature Tc was found to be ~30 K at 197 GPa in the sample that was synthesized at the same pressure with ~2000 K heating. The transitions are shifted to low temperature upon applying magnetic fields that supports the superconductivity nature. The upper critical field at zero temperature μ0Hc2(0) of the superconducting phase is estimated to be ~20 T that corresponds to GL coherent length ~40 angstroms. Our results suggest that the superconductivity may arise from I-43d phase of TaH3. It is, for the first time to our best knowledge, experimental realization of superconducting hydrides for the VB group of transitional metals.

cond-mat.supr-con↗

arXiv2023

Parity-time-symmetric two-qubit system: entanglement and sensing

In this paper we study exceptional-point (EP) effects and quantum sensing in a parity-time (PT)-symmetric two-qubit system with the Ising-type interaction. We explore EP properties of the system by analyzing degeneracy of energy eigenvalues or entanglement of eigenstates. We investigate entanglement dynamics of the two qubits in detail. In particular, we demonstrate that the system can create the steady-state entanglement in the PT-broken phase and collapse-revival phenomenon of entanglement in the PT-symmetric phase during the long-time evolution. We show that entanglement can be generated more quickly than the corresponding Hermitian system. Finally, we prove that the sensitivity of eigenstate quantum sensing for the parameters exhibits the remarkable enharncement at EPs, and propose a quantum-coherence measurement to witness the existence of EPs.

quant-ph↗

arXiv2023

Secrecy Capacity Analysis of 4-WFRFT Based Physical Layer Security in MIMO System

The traditional information security based on cryptosystem is seriously threatened due to the exponential growth of computing capacity. In order to improve for the upper cryptosystem security, the secure transmission at the physical layer is introduced into the wireless communication system. However, considering the openness of wireless channel, the performance analysis of security wireless communication systems has become a hot issue in recent years. Due to the existence of the upper layer cryptosystem being cracked and the openness of wireless channel security problems, the Multiple-Input Multiple-Output (MIMO) technology increases the difference between channels, the development of its rich spatial degrees of freedom can greatly improve the channel capacity and achieve the purpose of enhancing the Physical layer security (PLS); On this basis, Weighted Type Fractional Fourier Transform (WFrFT) technology rotates and splits the constellation points of signals, it is equivalent to increasing the artificial noise to enhance the PLS. The Average security capacity is an important index to measure the PLS, Therefore, this paper deduces the Average security capacity in MIMO scenario and gives a specific closed expression when considering the channel correlation. By analyzing the expression, the increase of the number of MIMO antennas will improve the Average security capacity. When the estimated bias is 1 in 4-WFRFT, the Average security capacity will be significantly improved; the Average security capacity will reach the maximum value, thus enhancing the PLS.

eess.SP↗

arXiv2023

Diffusion of muonic hydrogen in hydrogen gas and the measurement of the 1$s$ hyperfine splitting of muonic hydrogen

The CREMA collaboration is pursuing a measurement of the ground-state hyperfine splitting (HFS) in muonic hydrogen ($μ$p) with 1 ppm accuracy by means of pulsed laser spectroscopy. In the proposed experiment, the $μ$p atom is excited by a laser pulse from the singlet to the triplet hyperfine sub-levels, and is quenched back to the singlet state by an inelastic collision with a H$_2$ molecule. The resulting increase of kinetic energy after this cycle modifies the $μ$p atom diffusion in the hydrogen gas and the arrival time of the $μ$p atoms at the target walls. This laser-induced modification of the arrival times is used to expose the atomic transition. In this paper we present the simulation of the $μ$p diffusion in the H$_2$ gas which is at the core of the experimental scheme. These simulations have been implemented with the Geant4 framework by introducing various low-energy processes including the motion of the H$_2$ molecules, i.e. the effects related with the hydrogen target temperature. The simulations have been used to optimize the hydrogen target parameters (pressure, temperatures and thickness) and to estimate signal and background rates. These rates allow to estimate the maximum time needed to find the resonance and the statistical accuracy of the spectroscopy experiment.

physics.atom-ph↗

arXiv2023

Hybrid Optimization of Laser-Driven Fusion Targets and Laser Profiles

Quasi-isentropic compression is an effective method to achieve high-density and high-temperature implosion in laser-driven inertial confinement fusion (ICF). However, it requires precise matching between the laser profile and the target structure. Designing the optimal laser profile and the corresponding target for ICF is a challenge due to the large number of parameters involved. In this paper, we present a novel method that combines random walk and Bayesian optimization. The basic sampling data for Bayesian optimization are a series of laser pulse profiles and target structures that can produce relatively high areal densities obtained by the random walk method. This approach reduces the number of samples required for Bayesian optimization and mitigates low efficiency in the latter stages of the random walk method. The method also reduces the randomness in the optimization process and enhances the optimization efficiency. It should have important applications in ICF research.

physics.plasm-ph↗

arXiv2023

What can a GNOME do? Search targets for the Global Network of Optical Magnetometers for Exotic physics searches

Numerous observations suggest that there exist undiscovered beyond-the-Standard-Model particles and fields. Because of their unknown nature, these exotic particles and fields could interact with Standard Model particles in many different ways and assume a variety of possible configurations. Here we present an overview of the Global Network of Optical Magnetometers for Exotic physics searches (GNOME), our ongoing experimental program designed to test a wide range of exotic physics scenarios. The GNOME experiment utilizes a worldwide network of shielded atomic magnetometers (and, more recently, comagnetometers) to search for spatially and temporally correlated signals due to torques on atomic spins from exotic fields of astrophysical origin. We survey the temporal characteristics of a variety of possible signals currently under investigation such as those from topological defect dark matter (axion-like particle domain walls), axion-like particle stars, solitons of complex-valued scalar fields (Q-balls), stochastic fluctuations of bosonic dark matter fields, a solar axion-like particle halo, and bursts of ultralight bosonic fields produced by cataclysmic astrophysical events such as binary black hole mergers.

hep-ph↗

arXiv2023

Experimental examination of the alleged influence of cultural differences on single-file pedestrian fundamentals

Multiple studies have addressed what influences the fundamental diagram in single-file experiments. Several studies indicate that there are differences by gender when group composition is taken into account. Even for the simplest systems, such as pedestrian flows in corridors, there are still some deficiencies in the detailed understanding of this fundamental relationship. The effect of cultural differences can only be seen in a different density and velocity interval if a comparison is conducted between the two different cultural groups. Our results indicate that the velocities of male and female pedestrians are different. For instance, when N = 20, the velocity is 0.65 to 0.69m/s for Chinese, while for Ghanaians, the velocity is 0.51 to 0.62m/s. Similarly, when the densities change N = 40 in Chinese, they are 0.26 to 0.32m/s, while the Ghanaians are 0.21 to 0.28m/s. In addition, we investigated whether pedestrian behavior, corridor length, body weight, and height between Chinese and Ghanaian pedestrians influence cultural differences in a single-file fundamental diagram. Regression analysis makes it possible to determine whether there is a difference between the two groups.

physics.soc-ph↗

arXiv2023

Effect of non-local transport of hot electrons on the laser-target ablation

The non-local heat transport of hot electrons during high-intensity lasers interaction with plasmas can preheat the fuel and limit the heat flow in inertial confinement fusion. It increases the entropy of the fuel and decreases the final compression. In this paper, the non-local electron transport model that is based on the improved SNB algorithm has been embedded into the radiation hydrodynamic code and is benchmarked with two classical non-local transport cases. Then we studied a 2$ω$ laser ablating a CH target by using the non-local module. It is found that the non-local effect becomes significant when the laser intensity is above $1\times 10^{14} \mathrm{W/cm^{2}} $. The mass ablation rate from the SNB model is increased compared to that of the flux-limited model due to the lower coronal plasma temperature. This non-local model has a better agreement with the experimental results compared to that of the flux-limited model. The non-local transport is strongly dependent on the laser frequency, and the thresholds that the non-local transport should be considered are obtained for lasers of different frequencies. The appropriate flux-limiters that should be employed in the flux-limited model for different lasers are also presented. The results here should have a good reference for the laser-target ablation applications.

physics.plasm-ph↗

arXiv2023

Stopping power of high-density alpha-particle clusters in warm dense deuterium-tritium fuels

The state of burning plasma had been achieved in inertial confinement fusion (ICF), which was regarded as a great milestone for high-gain laser fusion energy. In the burning plasma, alpha particles incident on the cryogenic (warm dense) fuels cannot be simply regarded as single particles, and the new physics brought about by the density effects of alpha particles should be considered. In this work, the collective interaction between them has been considered, namely the effect of the superposition of wake waves. The stopping power of alpha-particle clusters, i.e. the rate of energy loss per unit distance traveled has been calculated using both analytical and simulation approaches. In theory, we obtain the stopping power of alpha clusters in cryogenic (warm dense) fuel by the dielectric function method, which illustrates the importance of the effective interaction between particles. Simulation results using the LAPINS code show that the collective stopping power of the alpha cluster is indeed increased via coherent superposition of excitation fields (the excitation of high-amplitude wake waves). However, the comparison between simulation and theoretical results also illustrates a coherent-decoherent transition of the stopping power of the cluster. The initial conditions with various sizes and densities of the alpha clusters have been considered to verify the condition of decoherence transition. Our work provides a theoretical description of the transport properties of high-density alpha particles in warm dense cryogenic fuel and might give some theoretical guidance for the design of actual fusion processes.

physics.plasm-ph↗