We present the first results of the search for sub-MeV fermionic dark matter absorbed by electron targets of germanium using the 205.4 kg . day data collected by the CDEX-10 experiment, with the analysis threshold of 160 eVee. No significant dark matter (DM) signals over the background are observed. Results are presented as limits on the cross section of DM-electron interaction. We present new constraints of cross section in the DM range of 0.1-10 keV/c(2) for vector and axial-vector interaction. The upper limit on the cross section is set to be 6.8 x 10(-46) cm(2) for vector interaction, and 2.3 x 10(-46) cm(2) for axial-vector interaction at DM mass of 5 keV/c(2).
We search for nuclear recoil signals of dark matter(DM)models with a light mediator using data taken from a p-type point-contact germanium detector of the CDEX-10 experiment at the China Jinping Underground Laboratory.The 90%confidence level upper limits on the DM-nucleon interaction cross section from 205.4 kg-day exposure data are derived,excluding the new parameter space in 2-3 GeV DM mass when the mediator mass is comparable to or lower than the typical momentum transfer.We further interpret our results to constrain a specific self-interacting DM model with a light mediator coupling to the photon through kinetic mixing and set experimental limits on the model parameter region favored by astrophysical observations.
Momentum space entanglement of four fermion field theory is calculated from the Wilsonian effective action pertubatively using replica trick, local terms in low energy effective action are proved to be nonrelevant pertubatively, and nonlocal terms are the only source of entanglement between different momentum modes. The final result can be represented by a set of basketball Feynman diagrams with new Feynman rules proposed to interpret them.
Magnetic pulse welding (MPW) has been widely applied to join metallic tubes in the automotive and aerospace fields. However, low energy utilization of the device limits the Lorentz force and the application to high-strength alloys. A novel hollow field shaper structure is proposed to expand the range of potentially applicable materials. Topology optimization was employed to trade off the efficiency and the strength of the device. The welding of 6061-T6 aluminum-alloy tube and 1020 steel tube was realized. The joint strength has increased threefold. The results showed that under the enhanced Lorentz force, the element was diffused into each other. The numerical study found that the Lorentz force from the novel design was enhanced by 56 %. The radial deformation in the free deformation experiment increased by 243.3 %, validating the improvement of the force. By creating an analytical model, it was analyzed that the increase in force was due to the decrease in current division on the sloping surface of the hollow field shaper. Besides, the efficiency increased by 66.7 % implying lower energy costs. Thus, the proposed structure was validated to expand the materials range of MPW.
We propose a new method to calculate perturbatively the isospectral Hermitian theory for the PT-symmetric i4'3 quantum field theory in d dimensions, whose result is local. The result of the new method in 1 dimension reproduces our previous result in the ix3 quantum mechanics, and the new method can be seen as a generalization of our previous method to quantum field theory. We also find the isospectral local Hermitian theory has the same form in all dimensions and differs in coefficients only, and our previous results in quantum mechanics can be used directly to determine the form of the isospectral local Hermitian quantum field theory.
Operating room (OR) is a critical and costly asset in hospitals. Effective management is crucial for cost reduction, improved patient outcomes, and resource optimization in ORs. To bolster operational efficiency, numerous hospitals have established day surgery centers for surgeries not requiring an overnight hospital stay. However, in order to effectively manage day surgeries, detailed analysis of workflow is needed, which is lacking in current literature. To address this gap, this letter presents to study workflow in day surgery centers. Using an absorbing Markov chain model for a single OR, an iterative algorithm is applied to compute daily performance metrics for systems incorporating multiple ORs, without succumbing to the curse of dimensionality. Numerical experiments and a case study confirm the accuracy and computational efficiency of the method.
RDMA-based in-memory storage systems offer high performance but are restricted by the capacity of physical memory. In this article, we propose TeRM to extend RDMA-attached memory with SSD. TeRM achieves fast remote access on the SSD-extended memory by eliminating page faults of RDMA NIC and CPU from the critical path. We also introduce a set of techniques to reduce the consumption of CPU and network resources. Evaluation shows that TeRM performs close to the performance of the ideal upper bound where all pages are pinned in the physical memory. Compared with existing approaches, TeRM significantly improves the performance of unmodified RDMA-based storage systems, including a file system and a key-value system.
First principles calculation is employed to investigate the crystal structure, electronic band structure, sites of the doped Eu2+ and the defect state in Ba2GdB2ClO6 with multi-coordination cation sites. The formation energies of Ba2GdB2ClO6 with Eu2+ substituting have been calculated and the doped Eu2+ prefers to substitute for Gd3+ and Ba2+ sites. The deficiency of O2- ions in the crystal structures will lead to the generation of defect state in the band gap and the deficiency of O2- usually occurred near Eu2+. Through the location of the defect state in the band gap and its composition, the electrons trapped in the defect state would be transferred to Eu2+ through the ways such as low energy light excitation, thermal activation and tunnelling. The defect state in the band structure plays an important role in the charge transfer process. Investigation into the defect state is quite important in the modulation of luminescence materials.
From the ancient Einstein-Podolsky-Rosen paradox to the recent Sorkin-type impossible measurements problem, the contradictions between relativistic causality, quantum non-locality, and quantum measurement have persisted. Our work provides a framework based on quantum field theory to harmoniously integrate these three aspects. This framework consists of causality expressed by reduced density matrices and an interpretation of quantum mechanics that considers quantum mechanics to be complete. Specifically, we utilize reduced density matrices to characterize the local information of the quantum state and demonstrate that they cannot evolve superluminally. Unlike recent approaches focusing on causality, we do not introduce new operators or fields specifically to describe detectors; instead, everything (including detectors, environments, and humans) is composed of the same fundamental fields, leading to complex renormalization. It is precisely these renormalization that prompts us to question the validity of the derivation of quantum paradoxes and lead us to propose a very natural and relativistically compatible interpretation of quantum mechanics.
While neutrino oscillations have led to attention and research on field mixing arising from quadratic interactions, the field mixing inherent in clothed particles is more fundamental, serving as a significant source of complexity and nonperturbative challenges in quantum field theory. We present an example of an analytical solution for field mixing involving a three-point interaction between a bosonic field and a fermionic field. Specifically, we study the Rothe-Stamatescu (RS) model and utilize lattice regularization to provide a well-defined Hamiltonian that is absent in the original continuous RS model. Because of the complexity introduced by three-point interactions compared to quadratic interactions, the Fock representation commonly used in discussions of field mixing does not work well; instead, we define a representation based on real space to investigate the physical vacuum and clothed particles. These eigenstates not only reveal the field mixing between the bosonic and fermionic fields but also allow us to directly observe the spatial entanglement structure.
We calculate the coefficients in the effective chiral Lagrangian from QCD, which includes pseudo-scalar mesons and vector mesons (with hidden symmetry), up to O(p4). This encompasses both the normal and anomalous parts. Our work builds on a previous study that derived the chiral Lagrangian from first principles of QCD, where the low-energy coefficients are defined in terms of specific Green's functions in QCD. This research extends our earlier efforts that focused on calculating the low-energy coefficients of the chiral Lagrangian for pure pseudo-scalar mesons. This marks the first calculation of chiral Lagrangian coefficients for vector mesons from QCD, particularly for the important parameters a and g, which are typically considered inputs in existing literature. Notably, the regularization method used previously is inadequate for this broader scope. We find that cut-off regularization yields reasonable results for both pseudo-scalar mesons and vector mesons, though it has certain limitations. Finally, we demonstrate that our method aligns with the Weinberg sum rules.
We operated a p-type point contact high purity germanium (PPCGe) detector (CDEX-1B, 1.008 kg) in the China Jinping Underground Laboratory (CJPL) for 500.3 days to search for neutrinoless double beta ($\bb$) decay of $^{76}$Ge. A total of 504.3 kg$\cdot$day effective exposure data was accumulated. The anti-coincidence and the multi/single-site event (MSE/SSE) discrimination methods were used to suppress the background in the energy region of interest (ROI, 1989--2089 keV for this work) with a factor of 23. A background level of 0.33 counts/(keV$\cdot$kg$\cdot$yr) was achieved. The lower limit on the half life of $^{76}$Ge $\bb$ decay was constrained as $T_{1/2}^{0\nu}\ > \ {1.0}\times 10^{23}\ \rm yr\ (90\% \ C.L.)$, corresponding to the upper limits on the effective Majorana neutrino mass: $\langle m_{\beta\beta}\rangle < $ 3.2--7.5$\ \mathrm{eV}$.
Constructing a superhydrophobic coating on cement-based materials' surface can effectively inhibit the invasion of external water and corrosive ions. However, current strategies of fabricating superhydrophobic coatings often require complex processes and some harmful solvents. Herein, an eco-friendly method is proposed for constructing superhydrophobic coatings on mortar surfaces to inhibit water penetration and chloride ion corrosion. The superhydrophobic coating was fabricated using superhydrophobic zeolite powders modified with nontoxic stearic acid. The mortar with superhydrophobic coating (SHC-mortar) possesses a water contact angle of 156 degrees and water slide angle of less than 10 degrees. In addition, the self-cleaning, waterproof and anticorrosion properties of SHC-mortar were explored. The results show that the fabricated superhydrophobic coating endows the mortar with a self-cleaning property, significantly reduces the capillary water absorption of the mortar, and improves the anticorrosion property of the mortar.
We present the first limit on g_Aγ coupling constant using the Bragg-Primakoff conversion based on an exposure of 1107.5 kg days of data from the CDEX-1B experiment at the China Jinping Underground Laboratory. The data are consistent with the null signal hypothesis, and no excess signals are observed. Limits of the coupling g_Aγ<2.08×10^-9 GeV^-1 (95% C.L.) are derived for axions with mass up to 100 eV/c^2. Within the hadronic model of KSVZ, our results exclude axion mass >5.3 eV/c^2 at 95% C.L.
Phosphogypsum (PG) is a solid waste generated by phosphate fertilizer industries that is currently used in concrete materials. However, adding PG to concrete usually results in reducing its water resistance and corrosion resistance. This paper presents a new method of applying PG to concrete to improve its water resistance. In this paper, a green superhydrophobic PG (SPG) coating was prepared using modified PG as a hydrophobic medium and cement as the bonding material. The contact angle between the superhydrophobic phosphogypsum coating (SPG coating) and water was 156 degrees, and the coating reached a superhydrophobic state with good self-cleaning ability. Even when sandpaper was used to polish the coating, the water contact angle of the coating was still greater than 150 degrees, indicating that the coating had good wear resistance. In addition, the results of water absorption and electrochemical experiments indicated that mortar coated with SPG had better water resistance and corrosion resistance than ordinary mortar. The SPG coatings with water resistance, wear resistance, and self-cleaning properties have potential applications in building exterior walls.
Physical systems which can be described by classical fields in classical theory, can also be described by quantum states in quantum field theory. We study the correspondence between the classical field and the quantum state which both describe the same physical systems. We derive the quantum states corresponding to the classical field in the representation expanded by the eigenstates of quantum field operators. This allows us to directly observe the spatial entanglement structure of quantum states and explore the differences and relationships between quantum superposition and classical superposition. According to the correspondence between classical observables and quantum states, we derive the equation of motion in classical theory from the evolution of quantum states in Yukawa theory. This leads to the relativistic classical Yukawa theory, and we further obtain relativistic corrections to the Yukawa potential.
CDEX-50 is a next-generation project of the China Dark Matter Experiment (CDEX) that aims to search for dark matter using a 50-kg germanium detector array. This paper comprises a thorough summary of the CDEX-50 dark matter experiment, including an investigation of potential background sources and the development of a background model. Based on the baseline model, the projected sensitivity of weakly interacting massive particle (WIMP) is also presented. The expected background level within the energy region of interest, set to 2–2.5 keVee, is ∼0.01 counts keVee^-1 kg^-1 day^-1. At 90% confidence level, the expected sensitivity to spin-independent WIMP-nucleon couplings is estimated to reach a cross-section of 5.1 × 10^-45 cm^2 for a WIMP mass of 5 GeV/c^2 with an exposure objective of 150 kg·year and an analysis threshold of 160 eVee. This science goal will correspond to the most sensitive results for WIMPs with a mass of 2.2–8 GeV/c^2.
Recently a dark matter-electron (DM-electron) paradigm has drawn much attention. Models beyond the standard halo model describing DM accelerated by high energy celestial bodies are under intense examination as well. In this Letter, a velocity components analysis (VCA) method dedicated to swift analysis of accelerated DM-electron interactions via semiconductor detectors is proposed and the first HPGe detector-based accelerated DM-electron analysis is realized. Utilizing the method, the first germanium based constraint on sub-GeV solar reflected DM-electron interaction is presented with the 205.4 kg·day dataset from the CDEX-10 experiment. In the heavy mediator scenario, our result excels in the mass range of 5-15 keV/c^{2}, achieving a 3 orders of magnitude improvement comparing with previous semiconductor experiments. In the light mediator scenario, the strongest laboratory constraint for DM lighter than 0.1 MeV/c^{2} is presented. The result proves the feasibility and demonstrates the vast potential of the VCA technique in future accelerated DM-electron analyses with semiconductor detectors.
We propose a new method to calculate perturbatively the isospectral Hermitian theory for the 𝒫𝒯-symmetric iϕ^3 quantum field theory in d dimensions, whose result is local. The result of the new method in 1 dimension reproduces our previous result in the ix^3 quantum mechanics, and the new method can be seen as a generalization of our previous method to quantum field theory. We also find the isospectral local Hermitian theory has the same form in all dimensions and differs in coefficients only, and our previous results in quantum mechanics can be used directly to determine the form of the isospectral local Hermitian quantum field theory.
We report new constraints on light dark matter (DM) boosted by blazars using the 205.4 kg day data from the CDEX-10 experiment located at the China Jinping Underground Laboratory. Two representative blazars, TXS 0506+56 and BL Lacertae are studied. The results derived from TXS 0506+56 exclude DM-nucleon elastic scattering cross sections from 4.6× 10^-33 cm^2 to 1×10^-26 cm^2 for DM masses between 10 keV and 1 GeV, and the results derived from BL Lacertae exclude DM-nucleon elastic scattering cross sections from 2.4× 10^-34 cm^2 to 1×10^-26 cm^2 for the same range of DM masses. The constraints correspond to the best sensitivities among solid-state detector experiments in the sub-MeV mass range.