Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. Subjects: Computer Science >> Other Disciplines of Computer Science submitted time 2024-05-14
Abstract： In his 1950 paper cite{Turing1950}, Turing proposed the notion of a thinking machine, namely a machine that can think. But a thinking machine has to follow a certain law of physics, provided it is realized physically. In this paper, we show that Turing’s thinking machine necessrily obeys ’t Hooft’s principle of superposition of states, which was presented by ’t Hooft cite{Hooft2016} in 2016 beyond the usual one as described by Dirac cite{Dirac1958} in the conventional quantum mechanics. Precisely, Turing’s thinking machine must be a quantum machine, while ’t Hooft’s principle characterizes its thinking behavior in a probabilistic way.
Peer Review Status:
Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2024-05-11
Abstract： Reliable calculations of nuclear binding energies are crucial for advancing the research of nuclear physics. Machine learning provides an innovative approach to exploring complex physical problems. In this study, the nuclear binding energies are modeled directly using a machine-learning method called the Gaussian process. First, the binding energies for 2238 nuclei with Z > 20 and N > 20 are calculated using the Gaussian process in a physically motivated feature space, yielding an average deviation of 0.046 MeV and a standard deviation of 0.066 MeV. The results show the good learning ability of the Gaussian process in the studies of binding energies. Then, the predictive power of the Gaussian process is studied by calculating the binding energies for 108 nuclei newly included in AME2020. The theoretical results are in good agreement with the experimental data, reflecting the good predictive power of the Gaussian process. Moreover, the α-decay energies for 1169 nuclei with 50 ≤ Z ≤ 110 are derived from the theoretical binding energies calculated using the Gaussian process. The average deviation and the standard deviation are, respectively, 0.047 MeV and 0.070 MeV. Noticeably, the calculated α-decay energies for the two new isotopes 204Ac M. H. Huang et al., Phys. Lett. B 834, 137484 (2022) and 207Th H. B. Yang et al., Phys. Rev. C 105, L051302 (2022) agree well with the latest experimental data. These results demonstrate that the Gaussian process is reliable for the calculations of nuclear binding energies. Finally, the α-decay properties of some unknown actinide nuclei are predicted using the Gaussian process. The predicted results can be useful guides for future research on binding energies and α-decay properties.
Subjects: Physics >> Nuclear Physics submitted time 2024-05-10
Abstract： [Background]: The China Spallation Neutron Source (CSNS) provides a white neutron beam with an energy range from 0.5 eV to 300 MeV and a total beam intensity of up to 107n/s/cm2, serving as an excellent experimental platform for the measurement of neutron capture reaction cross sections. During normal operation, the CSNS generates two proton bunches separated by 410 ns, consecutively striking the target, resulting in a mixed neutron beam composed of two bunches with a 410 ns interval. To avoid interference between the effects of the two bunches and maintain the energy precision of neutron capture cross sections, experimental data need to be analyzed and reconstructed to restore the effects of individual bunches. [Purpose]: The existing parsing method can yield very refined unfolding results, but it is relatively complex and has a certain usage threshold. Therefore, a more convenient data processing method needs to be found. [Methods]: This work utilized mathematical operations to analyze and reconstruct the data, with 410 ns as the unit time, and processed the data with a channel width of 4100 ns. Additionally, a comparison was made of the impacts of this method and existing methods on the accuracy of neutron incident energy. [Results]: This work proposes a simplified data processing method that achieves the same energy resolution as existing methods in the low-to-medium energy range, providing a new data processing approach for similar experimental work. [Conclusions]: The simplified data processing method presented in this study effectively addresses the issue of excessive computational costs in analyzing low to medium energy neutron data from the CSNS. It offers a practical solution for experimental work requiring accurate analysis of neutron capture reactions in this energy range.
Subjects: Physics >> Nuclear Physics submitted time 2024-05-08
Abstract： Complementary Metal Oxide Semiconductor (CMOS) image sensor is gradually replacing CCD image sensor with small size, light weight, low power consumption, high integration and other characteristics. In the space radiation environment, it has protons, heavy particles, gamma rays, A large number of high-energy particles such as electrons, CMOS image sensors will be subject to the radiation effect of heavy ions and have permanent damage to them.This paper focuses on the mechanism of permanent damage of CMV4000 under heavy ion irradiation. CMV4000 images after heavy ion irradiation have obvious hot pixels (the dark current peak is several times higher than the dark current peak of other pixels usually shows that the gray value of the pixel is several times higher than that of other normal pixels), and the hot pixels will not disappear in the next frame image and subsequent images, so the hot pixels are not temporary.This paper also considers the comparison of image parameters of CMOS image sensor before and after irradiation and reveals the degradation mechanism of each parameter.
Subjects: Engineering and technical science >> Physics Related Engineering and Technology Subjects: Engineering and technical science >> Technology of Instrument and Meter Subjects: Electronics and Communication Technology >> Electron Technology Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology submitted time 2024-05-06
Abstract： In this work, a design of transimpedance amplifier (TIA) for cryogenic scanning tunneling microscope (CryoSTM) is proposed. The TIA with the tip-sample component in CryoSTM is called as CryoSTM-TIA. With transimpedance gain of 1 Gohm, the bandwidth of the CryoSTM-TIA is larger than 200 kHz. The distinctive feature of the proposed CryoSTM-TIA is that its pre-amplifier is made of a single cryogenic high electron mobility transistor (HEMT), so the apparatus equivalent input noise current power spectral density at 100 kHz is lower than 6 (fA)2/Hz. In addition, bias-cooling method can be used to in-situ control the density of the frozen DX- centers in the HEMT doping area, changing its structure to reduce the device noises. With this apparatus, fast scanning tunneling spectra measurements with high-energy-resolution are capable to be performed. And, it is capable to measure scanning tunneling shot noise spectra (STSNS) at the atomic scale for various quantum systems, even if the shot noise is very low. It provides a powerful tool to investigate novel quantum states by measuring STSNS, such as detecting the existence of Majorana bound states in the topological quantum systems.
Peer Review Status:Awaiting Review
Subjects: Electronics and Communication Technology >> Electron Technology Subjects: Engineering and technical science >> Technology of Instrument and Meter Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology Subjects: Physics >> Condensed Matter: Electronic Structure, Electrical, Magnetic, and Optical Properties submitted time 2024-05-06
Abstract： In this work, we design and fabricate the transimpedance Amplifier (TIA) following the design mentioned in Ref. 1 . In the TIA, the preamplifier (Pre-Amp) is made of a junction field effect transistor (JFET) that can work at 77 K. The post-amplifier (Post-Amp) is made of an operational amplifier. Cascade Pre-Amp and Post-Amp to form the inverting-amplifier. With a 1.13 Gohm feedback network, the gain of TIA is 1.13 Gohm and its bandwidth is about 97 kHz. The equivalent input noise voltage power spectral density of TIA is not more than 9 (nV)2/Hz at 10 kHz and 4 (nV)2/Hz at 50kHz, and its equivalent input noise current power spectral density is about 26 (fA)2/Hz at 10 kHz and 240 (fA)2/Hz at 50 kHz. The measured transport performances and noise performances of TIA are consistent with the simulations and calculations. As an example, the realization of TIA in this work verifies the design method and analytical calculations for the low-noise large-bandwidth high-gain TIA proposed in Ref. 1,2 . And, the TIA in this work is perfect for the cryogenic STM working at liquid nitrogen temperature.
Peer Review Status:Awaiting Review
Subjects: Physics >> Nuclear Physics Subjects: Biology >> Radiobiology submitted time 2024-05-06
Abstract： Manned spaceflight and nuclear technology applications are running on a highway in China today. The radiation and nuclear safety will continue to be a major national demand in a long term. Thus, the continuous observation of new radiation protection molecular targets and related drugs is of great value to us. Our previous study has found that the circulating Insulin-like Growth Factor Binding Protein 3 (IGFBP-3) showed a significant increase after total body exposure of mice to ionizing radiation. However, the function of IGFBP-3 and the effects of it level change on radiation induced damages are still unclear. In this study, we set up the Igfbp3 gene overexpression and knock-down cell models in mouse Kupffer (MKC) cells. The CCK-8 assay, EdU assay, clone formation assay and microsphere phagocytosis experiment were performed for investing the proliferation activity, DNA replication activity and phagocytic ability of different cell models after carbon-ion irradiation. Moreover，mice were tail vein injected with recombinant IGFBP-3 protein at 2 hours before 5 Gy carbon-ion irradiation, and the survival curves of mice were drawn. The results showed that overexpression of IGFBP-3 protein significantly alleviated the radiation-induced decrease of the DNA replication activity, cell viability, clone formation rate, and phagocytic ability of MKC cells. On the contrary, the knock-down of IGFBP-3 protein expression reduced the above results. Injection of IGFBP-3 protein before carbon-ion exposure significantly delayed the time of death in mice. Our results indicate at the cellular and animal levels that IGFBP-3 protein has the potential to reduce radiation-induced damages and serve as a target for radiation protection. Through enhancing the radiation resistance and phagocytic ability of Kupffer cells in mice to reduce the risk of infection after radiation exposure might be the underlying mechanism of the effects of IGFBP-3 on radiation protection.
Subjects: Physics >> Nuclear Physics submitted time 2024-04-28
Abstract： The high-intensity heavy-ion accelerator facility (HIAF) is a scientific research facility complex composed of
multiple cascade accelerators of different types, which pose a scheduling problem for devices distributed over
a certain range of 2 km, involving over a hundred devices. The White Rabbit (WR), a technology-enhancing
Gigabit Ethernet, has shown the capability of scheduling distributed timing devices but still faces the challenge
of obtaining real-time synchronization calibration parameters with high precision. This study presents a calibra#2;
tion system based on a time-to-digital converter implemented on an ARM-based System-on-Chip (SoC). The
system consists of four multi-sample delay lines, a bubble-proof encoder, an edge controller for managing data
from different channels, and a highly effective calibration module that benefits from the SoC architecture. The
performance was evaluated with an average RMS precision of 5.51 ps by measuring the time intervals from 0
to 24000 ps with 120000 data for every test. The design presented in this study refines the calibration precision
of the HIAF timing system. This eliminates the errors caused by manual calibration without efficiency loss and
provides data support for fault diagnosis. It can also be easily tailored or ported to other devices for specific
applications and provides more space for developing timing systems for particle accelerators, such as white
rabbits on HIAF.
Subjects: Physics >> Nuclear Physics submitted time 2024-04-28
Abstract： The Shanghai Laser Electron Gamma Source (SLEGS, located in BL03SSID) beamline at the Shanghai Synchrotron Radiation Facility (SSRF) is a laser Compton scattering (LCS) gamma source used for the investigation of nuclear structure, which is in extensive demand in fields such as nuclear astrophysics, nuclear cluster structure, polarization physics, and nuclear energy. The beamline is based on the inverse Compton scattering of 10640 nm photons on 3.5 GeV electrons and a gamma source with variable energy by changing the scattering angle from 20° to 160°. γ-rays of 0.25–21.1 MeV can be extracted by the scheme consisting of the interaction chamber, coarse collimator, fine collimator, and attenuator. The maximum photon flux for 180° is approximately 10^7 photons/s at the target at 21.7 MeV, with a 3-mm diameter beam. The beamline was equipped with four types of spectrometers for experiments in (γ,γ’), (γ,n), and (γ,p α). At present, nuclear resonance fluorescence (NRF) spectrometry, flat efficiency neutron detector (FED) spectrometry, neutron time-of-flight (TOF) spectrometry, and light-charged particle (LCP) spectrometry methods have been developed.
Subjects: Physics >> Nuclear Physics Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-04-28
Abstract： A charged particle array, named MATE-PA, which serves as an auxiliary detec#2;tor system to the Multi-purpose Active-target Time projection chamber for nuclear astrophysical and exotic beam Experiments (MATE) has been con#2;structed. The array is composed of twenty single-sided strip-silicon detectors, covering around 10% of the solid angle. It is dedicated for the detection of reaction-induced charged particles which penetrate the MATE active volume. The performance of MATE-PA has been experimentally studied using an alpha source, and a 36-MeV 14N beam injected into the chamber of MATE, filled with a mixture gas of 95% 4He and 5% CO2 under the pressure of 500 mbar, at the Radioactive Ion Beam Line in Lanzhou (RIBLL). The results demonstrate good separation of light charged particles with the forward double-layer silicon detectors of MATE-PA. The energy resolution of the Si detectors was deduced to be about 1% (σ) for an energy loss of about 10 MeV by the α particles. The inclusion of MATE-PA helps improve particle identification, and increases the dynamic range for the kinetic energy of charged particles, in particular that of α particles up to about 15 MeV.
Subjects: Physics >> Nuclear Physics submitted time 2024-04-28
Abstract： Capacitors are widely used in pulsed magnet power supplies to reduce ripple voltage, store energy, and decrease power variation. In this study, DC-link capacitors in pulsed power supplies were investigated. By deriving an analytical method for the capacitor current on the H-bridge topology side, the root-mean-square value of the capacitor current was calculated, which helps in selecting the DC-link capacitors. The proposed method solves this problem quickly and with high accuracy. The current reconstruction of the DC-link capacitor is proposed to avoid structural damage in the capacitor’s current measurement, and the capacitor’s hot spot temperature and temperature rise are calculated using the FFT transform. The test results showed that the error between the calculated and measured temperature increases was within 1.5 ◦C. Finally, the lifetime of DC-link capacitors was predicted based on Monte Carlo analysis. The proposed method can evaluate the reliability of DC-link capacitors in a non-isolated switching pulsed power supply for accelerators and is also applicable to film capacitors.
Subjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties submitted time 2024-04-22
Abstract： Electron-diffraction patterns with 5-fold rotational symmetry of experimental alloy phases are assumed to be produced by periodic structures. A three-dimensional periodic structures is presented based on two kind polyhedrons. These structures can be used as an atomic model to describe the alloy phases. The Fourier-transform patterns of the models are found to be similar to the corresponding electron-diffraction patterns of these alloy phases along three “symmetry directions”. Details of the motivations and approaches that lead to these models are discussed.
Peer Review Status:Awaiting Review
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. submitted time 2024-04-22
Abstract： The possibility of Lorentz symmetry breaking has been discussed in many models of quantum gravity. In this paper we followed the Lorentz violation model in Ref. 14 to discuss the Doppler frequency shift of photons and the Compton scattering process between photons and electrons, pointing out that following the idea in Ref. 14 we have to modify the usual quantum relation of photons involved in the Doppler effect. But due to the current limited information and knowledge, we couldn’t yet determine the specific expression for the correction coefficient of the quantum relation of photons. However, the phenomenon of spontaneous radiation in a cyclotron maser give us an opportunity to see what the expression for this correction coefficient might look like, as the phenomenon of spontaneous radiation in a cyclotron maser can be explained by the Doppler effect of virtual photons and the Compton scattering process between virtual photons and electrons (or other particles). Therefore, under some restrictive conditions, we construct a very concise expression for this correction coefficient by discussing different cases. And then we used this expression to analyze the wavelength of radiation in the cyclotron maser, which tends to be a limited value at v→c, rather than to be 0 as predicted by the Lorentz model.And we also discussed the inverse Compton scattering phenomenon and found that there is a limit to the maximum
energy that can be obtained by photons in the collision between ultra-high energy particles and low-energy photons, which conclusion is also very different from that obtained from the Lorentz model, in which the energy that can be obtained by the photon tends to be infinite as the velocity of particle is close to c. This paper still inherits the idea in Ref. 14 that the energy and momentum of particles (i.e., any particles, including photons) cannot be infinite, otherwise it will
make some physical scenarios meaningless, and this view is also from the idea in some quantum gravity models. When the parameter Q characterizing the degree of deviation from the Lorentz model is equal to 0, all the results and conclusions in this paper will return to the case as in the Lorentz model, so this paper also provides us with a possible experimental scheme to determine the value of Q in Ref. 14 , although it still requires extremely high experimental energy.
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Celestial Mechanics Subjects: Physics >> Geophysics, Astronomy, and Astrophysics submitted time 2024-04-20
Abstract： This article presents a brief introduction to a systematic improvement in celestial dynamics theory through the introduction of a new symmetrical form of particle dynamics equation. For open multi-body systems where it is challenging to find a highly accurate inertial reference frame, approximations of inertial frames need to be introduced. However, the new symmetric equation can be applied to any translational reference frame, thus avoiding the need for inertial reference frame approximations and enhancing the accuracy of theoretical predictions. In the case of bound multi-body systems, the traditional approach involves introducing a center of mass reference frame, applying Newton’s second law in this frame, and then transforming it back to the actual reference frame, such as the perturbation equation of the solar system’s planets. Conversely, applying the new symmetric equation allows for the direct derivation of planetary perturbation equations. Furthermore, by considering temporary thrust or impact forces acting on planets, or to further enhance computational precision, even considering any external forces acting on the bound system, then a new correction equation has been established for the planetary perturbation equation that can be further imposed with non-perturbative interactions.
Peer Review Status:Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2024-04-18
Abstract： Based on the dinuclear system model, the calculated evaporation residue cross sections matched well with the current experimental results. The synthesis of superheavy elements Z = 121 was systematically studied through combinations of stable projectiles with Z = 21–30 and targets with half-lives exceeding 50 d. The influence of mass asymmetry and isotopic dependence on the projectile and target nuclei was investigated in detail. The reactions 254Es (46Ti, 3n) 297121 and 252Es (46Ti, 3n) 295121 were found to be experimentally feasible for synthesizing superheavy element Z = 121, with maximal evaporation residue cross sections of 6.619 and 4.123 fb at 219.9 and 223.9 MeV, respectively.
Subjects: Physics >> Condensed Matter: Electronic Structure, Electrical, Magnetic, and Optical Properties submitted time 2024-04-17
Shuqiang He
Yi-Feng Zheng
Guosheng Shi
Yi-Jie Xiang
Meihui Xiao
Qituan Zhang
Yue-Yu Zhang
Haiping Fang
Abstract： The identification of new materials with superconducting properties is the pursuit in the realm of superconductivity research. Here, excitedly, we show that the simplest salt daily used can be made a superconductor at normal pressure only by adjusting its stoichiometry of Na and Cl as Na3Cl at normal pressure based on first-principles calculations. This bulk stable abnormal Na-Cl stoichiometric crystal of 3:1, the first ‘magic’ ratio, includes metallic (Na) atoms in the core as well as hybridization of ionic and metallic bonding, facilitating the electron-phonon-coupling for superconductivity with a critical temperature Tc of 0.13 K. The flat bands and van Hove singularities near the Fermi level produce large densities of states, similar to H3S and LaH10, which is beneficial for the emergence of superconductivity. The crystal composed of with abnormal Na-Cl magic stoichiometry is a precisely tunable, purely sodium and chloride-based, three-dimensional bulk superconductor, which is therefore an ideal material for designing and understanding abnormal stoichiometric crystals. The methodology of constructing this bulk abnormal crystal may be general to almost all elements, which could lead to insights into the physics of other conventional superconductors and even high-critical-temperature superconductors.
Peer Review Status:Awaiting Review
Subjects: Physics >> Nuclear Physics Subjects: Physics >> The Physics of Elementary Particles and Fields submitted time 2024-04-15
Abstract： The search for chiral magnetic effects (CME) in relativistic heavy-ion collisions helps us to understand CP symmetry breaking in strong interactions and the topological nature of the quantum chromodynamic (QCD) vacuum. A two-plane method was proposed based on the fact that the background and signal of CME have different correlations relative to the spectator plane and the participant plane. Using a multiphase transport model with different input strengths of CME, we revisit the two-plane method in isobar collisions at √sNN = 200 GeV. The relative correlations of the CME signal and background to two different planes were found to be different, which is inconsistent with the assumptions made in the current experimental measurements. The difference arises from the decorrelation of the CME relative to the spectator and participant planes, which originates from the final state interactions. Our finding suggests that the current experimental measurements may overestimate the fraction of the CME signal in the final state in relativistic heavy-ion collisions.
Subjects: Physics >> Nuclear Physics submitted time 2024-04-12
Abstract： A systematic comparison of the odd-$A$ cobalt isotopes $^{53-65}$Co’s negative parity halo states energy level structures indicates a level inversion between $9/2^-$ and $11/2^-$ in $^{55}$Co, and suggests that $^{53,57}$Co might exhibit strong collective effects. Shell model calculations based on the GXPF1A effective interaction reproduce well these nuclei’s halo state energy levels, along with the corresponding experimental values for magnetic moments and electric quadrupole moments. The shell model results show that the dominant proton configuration component in the ground state $7/2^-$ wave functions of $^{53-65}$Co is $ pi left(1f_{7/2} right)^7$. The excited states $9/2^-$ and $11/2^-$ in $^{55}$Co involve a competition between $1f_{7/2}$ proton excitation and $1f_{7/2}$ neutron excitation, leading to a possible level inversion between the $9/2^-$ and $11/2^-$ states. Moreover, using the Constrained Hartree-Fock (CHF) method to study the quadrupole deformation characteristics of $^{53,55,57}$Co, and combining the average occupancy numbers and configurations obtained from shell model calculations, the reasons why the excited state energies of $^{55}$Co are higher compared to other Co isotopes were analyzed.
Subjects: Information Science and Systems Science >> Basic Disciplines of Information Science and Systems Science Subjects: Physics >> Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics, and Fluid Dynamics Subjects: Astronomy >> Astrophysical processes submitted time 2024-04-11
Abstract： The electromagnetic fields of point sources with time varying charges moving in the vacuum are derived using the Liénard-Wiechert potentials. The properties of the propagation velocities and the Doppler effect are discussed based on their far fields. The results show that the velocity of the electromagnetic waves and the velocity of the sources cannot be added like vectors; the velocity of electromagnetic waves of moving sources are anisotropic in the vacuum; the transverse Doppler shift is intrinsically included in the fields of the moving sources and is not a pure relativity effect caused by time dilation. Since the fields are rigorous solutions of the Maxwell’s equations, the findings can help us to abort the long-standing misinterpretations concerning about the classic mechanics and the classic electromagnetic theory. Although it may violate the theory of the special relativity, we show mathematically that, when the sources move faster than the light in the vacuum, the electromagnetic barriers and the electromagnetic shock waves can be clearly predicted using the exact solutions. Since they cannot be detected by observers in the region outside their shock wave zones, an intuitive and reasonable hypothesis can be made that the superluminal sources may be considered as a kind of electromagnetic blackholes.
Peer Review Status:Awaiting Review
Subjects: Physics >> The Physics of Elementary Particles and Fields submitted time 2024-04-10
Abstract： A theory of quantum reference frame is considered in the paper, the induced Ricci flow of quantum spacetime and gravity theory are discussed by considering the second order moment of the quantum fluctuation of the reference frame. We also discuss the cosmic acceleration (cosmological constant problem), radial acceleration discrepancy of galaxies, inflation in the early universe, and the origin of spacetime entropy. Finally, we propose some possible predictions of the theory.
Peer Review Status:Awaiting Review
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