Article
Astronomy & Astrophysics
Maxence Corman, William E. Easta, Justin L. Ripleyc
Summary: This article examines the classical dynamics of black holes in a non-singular cosmological background and finds that the black hole horizon can disappear during the contraction phase under certain conditions. However, this does not significantly affect most of the cosmic evolution. Regardless of the black hole's initial mass, its event horizon persists throughout the cosmological evolution, resulting in an expanding universe with a black hole whose mass is comparable to its initial value.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
A. Meenakshi McNamara, Sahil Saini, Parampreet Singh
Summary: In classical Bianchi I spacetimes, the singularity structure can be easily determined from the generalized Friedmann equation. However, in nonsingular bouncing anisotropic models, these insights are difficult to obtain in the quantum gravity regime. We address this problem in loop quantum cosmology and discover a surprising relationship between energy density and anisotropic shear at the bounce.
Article
Physics, Particles & Fields
Cyril Renevey, Aurelien Barrau, Killian Martineau
Summary: This study investigates the classic bounce that occurs when extrapolating the inflationary stage backward in time in a positively curved Universe. The research finds that the background dynamics of this scenario is mostly insensitive to initial conditions when considering observational consequences. Explicit calculations of the primordial scalar power spectrum and subsequent CMB temperature anisotropies are provided, with results being compatible with current measurements. However, some deviations with respect to the standard paradigm may occur at large scales, and the study carefully disentangles the contributions from the vacuum choice and the bounce itself.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Nanoscience & Nanotechnology
Yong Wu, Ronglei Fan, Minghe Chen, Kehuan Wang, Jie Zhao, Wenchao Xiao
Summary: The study focused on investigating the high-temperature anisotropy and microstructure evolution mechanisms of the rolled TA32 titanium alloy sheet. It was found that the TD sample exhibited the largest peak strength, while the DD sample displayed the highest elongation. The dominant dislocation slip modes for RD, DD, and TD samples were identified as prismatic slip, the coupling of basal and prismatic slips, and pyramidal slips, respectively. Furthermore, the DRX mechanism of TA32 titanium alloy during hot deformation was a combination of DDRX and CDRX, which could weaken the anisotropy.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Geology
Gillian B. Goldhagen, Heather A. Ford, Maureen D. Long
Summary: Using data from the SEISConn seismic experiment, this study characterizes the upper-mantle structure beneath southern New England. The researchers identify a well-defined lithosphere-asthenosphere boundary, a thin lithosphere, and a possible extension of the Northern Appalachian Anomaly. They also suggest the preservation of inherited structure in the present-day lithosphere.
Article
Materials Science, Multidisciplinary
Yan Zhao, Wenjie Guo, Hanlin Zhu, Yifeng He, Chao Jiang, Yanping Cao
Summary: This study explores the effect of curved surface features on the selection and evolution of wrinkle patterns in a soft bilayer system under compression. It is found that negative Gauss curvature promotes the sinusoidal/diamond-like mode transition, while positive Gauss curvature inhibits this pattern evolution.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2021)
Article
Chemistry, Physical
Hiroyuki Shima, Takashi Sumigawa, Yoshitaka Umeno
Summary: Dislocations are common defects in crystalline materials that greatly influence the deformation process and physical properties. However, describing the elastic field around dislocations mathematically is challenging due to theoretical difficulties such as singularities near the dislocation-core and nontrivial modulation near material interfaces. In this study, we develop an explicit formulation for the stress field generated by an edge dislocation near the zero-traction surface of an elastic medium, which does not exhibit nonphysical divergence near the dislocation-core like classical solutions. Our results allow for accurate estimation of the effect of the zero-traction surface on near-surface stress distribution and its dependence on the orientation of the Burgers vector. We evaluate the degree of surface-induced modulation in the stress field using the L-2 norm concept for function spaces and comparing it to the stress field in an infinitely large system without any surface.
Article
Astronomy & Astrophysics
Ivan Agullo, Dimitrios Kranas, V. Sreenath
Summary: The model discussed explores a scenario in the early universe where a cosmic bounce precedes the inflationary epoch, providing a common origin for several anomalous features observed in the cosmic microwave background (CMB) at large angular scales. These features include power suppression, dipolar asymmetry, and odd-parity correlations, with amplitude and scale dependence consistent with observations. Additionally, the model alleviates tension in the lensing amplitude.
GENERAL RELATIVITY AND GRAVITATION
(2021)
Article
Geosciences, Multidisciplinary
Zongjie Li, Li-Yun Fu, Jun Liu, Zhiwei Wang, Shikai Jian
Summary: This study focuses on the deep Ordovician fractured carbonates in northwest China, utilizing an integrated scheme with azimuthal P-P amplitude/frequency attributes for prestack prediction of fractures from migrated CRP gathers. The method proves effective in detecting superdeep fracture sets from seismic data with extremely low SNR, showcasing the applicability of coupled amplitude and frequency attributes for fracture prediction.
MARINE AND PETROLEUM GEOLOGY
(2022)
Article
Astronomy & Astrophysics
Tanmoy Paul, Soumitra Sengupta
Summary: This article presents an ekpyrotic bounce scenario driven by a second rank antisymmetric Kalb-Ramond field, where the universe undergoes contraction through an ekpyrotic stage with a non-singular bouncing behavior, and smoothly transitions to an expanding phase. The article provides important insights into the early evolution of the universe.
PHYSICS OF THE DARK UNIVERSE
(2023)
Article
Engineering, Biomedical
Sebastien J. P. Callens, Duncan C. Tourolle ne Betts, Ralph Muller, Amir A. Zadpoor
Summary: This research analyzes the local and global geometry of human trabecular bone through quantifying surface curvatures and Minkowski functionals, showing that curvature density maps provide distinct shape fingerprints for bones from different sites. The Minkowski analysis illustrates that trabecular bone exhibits other types of anisotropy/ellipticity beyond interfacial orientation and that anisotropy varies substantially within the trabecular structure.
ACTA BIOMATERIALIA
(2021)
Article
Astronomy & Astrophysics
Honghong Wu, Shiyong Huang, Xin Wang, Zhigang Yuan, Jiansen He, Liping Yang
Summary: In this study, the influence of intermittent structures on the spectral index and higher-order scaling behavior in near-Sun solar wind turbulence is investigated using magnetic field data measured by Parker Solar Probe. Results show that the multifractal scaling of the magnetic field can be predicted by the log-Poisson intermittency model, and a simple Kolmogorov -5/3 monoscaling recovers after the removal of intermittency. Similar behavior is also found for the scaling of the rotational angle, suggesting the involvement of magnetic discontinuities in the energy transfer process of solar wind turbulence.
ASTROPHYSICAL JOURNAL LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Vanuildo S. de Carvalho, Hermann Freire
Summary: We study the pairing instability in a two-dimensional metallic system induced by Ising-nematic quantum fluctuations, considering the relevant coupling between the nematic order parameter and the elastic modes (acoustic phonons) of the lattice. We find that this nematoelastic coupling leads to a decrease in both the superconducting critical temperature and the gap function, regardless of the gap symmetry. Moreover, we show that this coupling allows us to investigate the emergence of the superconducting phase from either a non-Fermi liquid or a Fermi liquid normal state at low temperatures, with different critical exponents characterizing the phase transitions.
Article
Energy & Fuels
Xiaoling Wang, Shaoqing Wang, Chen Hao, Yungang Zhao, Xiaoxia Song
Summary: The structural evolution of thermally altered coal underwent a tortuous process, with the eventual trend towards consistent orientation and the lowest curvature. As the samples approached the intrusion, the lattice fringe arrangement became more orderly and the curvature fluctuated.
Article
Physics, Applied
Cheng-Chao Hu, Zhao Zhang, Ting-Tao Cai, Yu-Xin Xu, Ji-Gong Hao, Yang-Guang Shi, Tian-Nan Yang, Long-Qing Chen
Summary: This study demonstrates the construction of a magnetic-ordering tricritical type MPB near room temperature in the TbxHo1-x(Fe0.9Co0.1)2 magnetostrictive system, achieving an ultrahigh magnetostrictive sensitivity and providing fundamental insights for designing ultrasensitive magnetostrictive materials.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Physics, Particles & Fields
Gabriele Montefalcone, Paul J. Steinhardt, Daniel H. Wesley
JOURNAL OF HIGH ENERGY PHYSICS
(2020)
Article
Chemistry, Multidisciplinary
Simone Tommasini, Luca Bindi, Maurizio Petrelli, Paul D. Asimow, Paul J. Steinhardt
Summary: This study conducted laser ablation inductively coupled plasma mass spectrometry measurements of trace element contents in two naturally occurring quasicrystalline minerals from the Khatyrka meteorite. The results revealed a unique pattern in the elemental composition, indicating significant differences compared to primitive solar system materials. Additionally, it was found that the natural quasicrystals contain 3-5% silicate and oxide nanopartide inclusions.
ACS EARTH AND SPACE CHEMISTRY
(2021)
Article
Multidisciplinary Sciences
Luca Bindi, William Kolb, G. Nelson Eby, Paul D. Asimow, Terry C. Wallace, Paul J. Steinhardt
Summary: This paper reports the discovery of a previously unknown anthropogenic quasicrystal composition in a sample of red trinitite, which is now known as one of the oldest existing quasicrystals with its creation time indelibly etched in history.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Physics, Multidisciplinary
Michael A. Klatt, Paul J. Steinhardt, Salvatore Torquato
Summary: Through numerical computations, we discovered universal behaviors in the gap sensitivity of photonic band gap structures, both in crystal and disordered networks, with a universal formula approximating the behavior in 1D quarter-wave stack structures. This universal behavior could provide insights into PBG formation and guidance for designing novel photonic heterostructures.
PHYSICAL REVIEW LETTERS
(2021)
Article
Astronomy & Astrophysics
Anna Ijjas, Frans Pretorius, Paul J. Steinhardt, Andrew P. Sullivan
Summary: It is demonstrated that the rapidity and robustness of slow contraction in homogenizing and flattening the universe are generally enhanced when initial variations are along two spatial directions, include multiple modes, and have reduced symmetry. Particularly significant are shear effects that only become possible when variations are allowed along two or more spatial dimensions. Based on numerical results, it is conjectured that this counterintuitive enhancement occurs because more degrees of freedom are activated, driving spacetime away from an unstable Kasner fixed point towards the stable Friedmann-Robertson-Walker fixed point.
Article
Astronomy & Astrophysics
Anna Ijjas, Paul J. Steinhardt
Summary: This paper tracks the evolution of entropy and black holes in a cyclic universe that undergoes repeated intervals of expansion and contraction. The study discovers that after each contraction, entropy naturally reaches near-maximal levels in the matter-radiation sector and near-minimal levels in the gravitational sector.
Article
Multidisciplinary Sciences
Cosmin Andrei, Anna Ijjas, Paul J. Steinhardt
Summary: In this paper, we investigate how short the remaining period of expansion can be given current observational constraints on dark energy, and discuss how this scenario fits naturally with cyclic cosmologies and recent conjectures about quantum gravity.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Multidisciplinary Sciences
Luca Bindi, Matthew A. Pasek, Chi Ma, Jinping Hu, Guangming Cheng, Nan Yao, Paul D. Asimow, Paul J. Steinhardt
Summary: We report the discovery of a dodecagonal quasicrystal Mn72.3Si15.6Cr9.7Al1.8Ni0.6, composed of a periodic stacking of atomic planes with quasiperiodic translational order and 12-fold symmetry along the two directions perpendicular to the planes, accidentally formed by an electrical discharge event in an eolian dune in Nebraska. The quasicrystal coexists with a cubic crystalline phase and was found in a fulgurite consisting predominantly of fused and melted sand along with traces of melted conductor metal from a downed power line. This discovery suggests the possibility of finding quasicrystals in other places and synthesizing them in the laboratory.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Multidisciplinary Sciences
Michael A. Klatt, Paul J. Steinhardt, Salvatore Torquato
Summary: This study investigates the formation of band gaps in different levels of ordered two-dimensional photonic network solids. The results show that the band gaps rapidly close as the system size increases, except for sufficiently stealthy hyperuniform cases.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Multidisciplinary Sciences
Qingxia Ma, Hongfei Jiang, Leina Ma, Gaoxiang Zhao, Qianqian Xu, Dong Guo, Ningning He, Hao Liu, Zhaoyuan Meng, Juanjuan Liu, Lei Zhu, Qian Lin, Xiaolin Wu, Min Li, Shudi Luo, Jing Fang, Zhimin Lu
Summary: It has been discovered that the expression levels of the glycolytic enzyme ENO1 are positively correlated with CHKa expression levels in human glioblastoma specimens. ENO1 regulates CHKa expression through post-translational modification. Mechanistically, highly expressed ENO1 in tumor cells binds to I199/F200 of CHKa, leading to the inhibition of TRIM25-mediated poly-ubiquitylation of CHKa at K195 and increased stability of CHKa. These findings provide insight into the integrated regulation of cancer metabolism by the crosstalk between glycolytic and lipidic enzymes.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Geochemistry & Geophysics
Chi Ma, Jinping Hu, Martin D. Suttle, Yunbin Guan, Thomas G. Sharp, Paul D. Asimow, Paul J. Steinhardt, Luca Bindi
Summary: A newly discovered micrometeorite from Sudan exhibits an exotic Al-Cu-Fe assemblage similar to that found in the Khatyrka chondrite. By analyzing oxygen isotope ratios and conducting transmission electron microscopy, researchers found evidence suggesting that the micrometeorite is most likely related to CR chondrites. The study also provides additional evidence for the occurrence of naturally-occurring Al-Cu alloys and suggests the existence of multiple pathways for the association of these two elements.
METEORITICS & PLANETARY SCIENCE
(2023)
Article
Physics, Multidisciplinary
Giorgi Tukhashvili, Paul J. Steinhardt
Summary: We demonstrate that fermion condensation of the Nambu-Jona-Lasinio type can lead to a nonsingular bounce that smoothly connects a phase of slow contraction to a phase of expansion. This approach avoids the problem of generating a large anisotropy and chaotic behavior.
PHYSICAL REVIEW LETTERS
(2023)
Article
Astronomy & Astrophysics
David Garfinkle, Anna Ijjas, Paul J. Steinhardt
Summary: We present the initial findings from a new numerical relativity code that uses a tetrad formulation of the Einstein-scalar field equations and recently introduced gauge/frame invariant diagnostics. The results provide evidence that inflation does not address the issue of homogeneity and isotropy starting from generic initial conditions after the big bang.
Article
Materials Science, Multidisciplinary
Latham Boyle, Paul J. Steinhardt
Summary: This study focuses on 1D quasilattices, particularly self-similar ones, which can be used to generate quasicrystalline tessellations with matching and invertible self-similar substitution rules. The study describes the geometric constructions and equivalence classes of these quasilattices and provides explicit transformation laws between quasilattices in the same class. The study also presents ten special self-similar 1D quasilattices relevant for constructing patterns in higher dimensions and explicitly constructs the corresponding self-same quasilattices.
Article
Materials Science, Multidisciplinary
Latham Boyle, Paul J. Steinhardt
Summary: This study presents a precise geometric relationship between various geometric patterns and expands the number of known examples. By identifying this relationship, the authors are able to systematically obtain these patterns and their properties, and complete the enumeration of quasicrystallographic space groups.
