Article
Physics, Multidisciplinary
Rong-Gen Cai, Shao-Jiang Wang
Summary: We have proposed a refined version of the trans-Planckian censorship conjecture (TCC) based on the strong scalar weak gravity conjecture and some entropy bounds. This refined TCC does not require fine-tuning on inflation model-building and passes tests from stringy examples supporting the original TCC. Additionally, it could be compatible with hilltop eternal inflation.
SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY
(2021)
Article
Multidisciplinary Sciences
Polina Petriakova, Arkady Popov, Sergey Rubin
Summary: Studying the evolution of the Universe from sub-Planckian scale to present times reveals the requirement for exponential expansion of space and significant restrictions on parameter values of a function f(R). The initial metric of the Universe is assumed to be maximally symmetric with positive curvature.
Article
Astronomy & Astrophysics
Norma G. Sanchez
Summary: This passage discusses the process of going back in time to complete the Standard Model of the universe, involving Planckian and transPlanckian physics, quantum vacuum energy, and the relationship between the de Sitter Universe and the cosmological constant. It also describes the quantum discrete cosmological levels and phases, as well as the implementation of the Snyder-Yang algebra for a consistent group-theory realization.
Article
Astronomy & Astrophysics
Norma G. Sanchez
Summary: We provide a quantum unifying picture for black holes, covering their main properties and including both classical and quantum domains. The novel findings of this paper reveal that black hole interiors are always quantum, trans-Planckian, and of constant curvature. The paper also presents the quantum Penrose diagram of the Schwarzschild-Kruskal black hole and discusses the complete partition function, entropy, temperature, and decay rate. The importance of this research lies in its contribution to our understanding of black holes and the trans-Planckian domain in the context of quantum gravity.
Article
Astronomy & Astrophysics
Suvadip Sinha, Om Gupta, Vishal Singh, B. Lekshmi, Dibyendu Nandy, Dhrubaditya Mitra, Saikat Chatterjee, Sourangshu Bhattacharya, Saptarshi Chatterjee, Nandita Srivastava, Axel Brandenburg, Sanchita Pal
Summary: Solar flares are difficult to predict due to the lack of unique triggers or pathways. Recent advancements in machine learning have improved flare forecasting techniques. This study compares four popular machine learning techniques and finds that logistic regression and support vector machines perform well in forecasting active region flaring potential. Magnetic properties such as total current helicity and vertical current density are found to be the top-performing flare indicators.
ASTROPHYSICAL JOURNAL
(2022)
Article
Materials Science, Multidisciplinary
Philipp T. Dumitrescu, Nils Wentzell, Antoine Georges, Olivier Parcollet
Summary: We numerically investigate a model of interacting spin-1/2 electrons on a fully connected lattice with random exchange coupling. Our results reveal the existence of a quantum critical point that separates two distinct metallic phases as a function of doping. In this quantum critical point, the system exhibits non-Fermi-liquid properties, including T-linear Planckian behavior, ??/T scaling, and slow spin dynamics of the Sachdev-Ye-Kitaev type.
Article
Physics, Particles & Fields
Dipankar Laya, Roshni Bhaumik, Subenoy Chakraborty
Summary: This work investigates a complex scalar field in scalar tensor gravity theory in the background of spatially flat Friedmann-Lemaitre-Robertson-Walker (FLRW) geometry. The classical cosmological solution of a scalar field in scalar-tensor theory with the scalar field as a nonminimally coupled complex field is determined using Noether symmetry analysis. In quantum cosmology, the Wheeler-DeWitt (WD) equation is formulated in the minisuperspace and the wave function of the universe is evaluated using the operator version of the conserved (Noether) charge. The nature of the classical solution and the cosmological singularity are discussed both classically and quantum mechanically.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Chemistry, Multidisciplinary
Hanbin Gao, Ning Guo, Yue Gong, Lu Bai, Dongwei Wang, Qiang Zheng
Summary: This study directly observed and quantified the inherent local fluctuating lattice distortions in four types of high-entropy oxides using advanced scanning transmission electron microscopy techniques. The findings provide valuable examples for future investigations on local fluctuating structures and their relationships with properties in more systems of high-entropy oxides.
Article
Astronomy & Astrophysics
Kim Berghaus, Tanvi Karwal
Summary: Thermal friction can solve the Hubble and the large-scale structure tensions by converting scalar field energy into dark radiation. The addition of extra radiation to the Universe can also mitigate the LSS tension. However, the CMB data is incompatible with linear density perturbations of the dark radiation when injected at redshifts close to matter-radiation equality.
Article
Biochemical Research Methods
Yanyan Diao, Feng Hu, Zihao Shen, Honglin Li
Summary: This article presents a new method, MacFrag, for efficient molecule fragmentation by utilizing a modified version of BRICS rules and an efficient subgraphs extraction algorithm. Evaluation results with ChEMBL dataset showed that MacFrag was faster overall than BRICS implemented in RDKit and modified molBLOCKS, and the fragments obtained through MacFrag were more compliant with the 'Rule of Three'.
Article
Physics, Particles & Fields
Ilia Komissarov, Alberto Nicolis, John Staunton
Summary: At high momenta above the Hubble scale, cosmological expansion can be viewed as a weak gravitational field. By using convenient coordinates, we can apply perturbation theory in Minkowski space to deal with the effects of expansion at those high momenta. This allows us to derive standard results of quantum field theory, such as mode-stretching and gravitational particle production, in a cosmological background. We discuss the implications of these results for the trans-Planckian problem.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Multidisciplinary Sciences
Harry Oslislo, Brett Altschul
Summary: This paper investigates the requirement for smoothness in the physical expansion of space, and examines the form of interpolating functions in the process of expansion using a geometric model. The study finds a cusp in the direct transition from inflation to subsequent eras, resulting in an order-of-magnitude increase in the size of the universe.
Article
Chemistry, Multidisciplinary
Jinwen Wang, Zheng Ren, Jing Pan, Xiaofeng Wu, Jiansheng Jie, Xiaohong Zhang, Xiujuan Zhang
Summary: For the first time, a method of anchored crystal-seed epitaxial growth is developed for wafer-scale growth of 2D organic semiconductor single crystals. The crystal seed is firmly anchored on the liquid surface, ensuring steady epitaxial growth. This approach effectively eliminates substrate defects and enhances the 2D growth of organic crystals, providing a new avenue for high-performance organic electronics.
ADVANCED MATERIALS
(2023)
Article
Geosciences, Multidisciplinary
Ping Lu, Clement Narteau, Zhibao Dong, Philippe Claudin, Sebastien Rodriguez, Zhishan An, Cyril Gadal, Sylvain Courrech du Pont
Summary: In this study, landscape-scale experiments conducted at the edge of the Gobi desert demonstrate the simultaneous development of various dune types under natural wind conditions. The researchers also found that the same wind regime can lead to two different dune orientations depending on sand availability, suggesting two independent dune growth mechanisms. The experimental field observations support existing theoretical models of dune dynamics, boosting confidence in their ability to predict dune evolution under different wind regimes and bed conditions.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Multidisciplinary Sciences
Richard P. Woodard
Summary: In this article, some reminiscences of the late Steven Weinberg are shared. Then, a topic in quantum field theory is discussed, which is the role of state wave functionals in deriving the ie term of the Feynman propagator when using functional formalism. While it may be a curiosity for in-out scattering amplitudes on flat-space backgrounds, it holds much greater significance for the in-in amplitudes of the Schwinger-Keldysh formalism in cosmology. It also addresses Weinberg's wonder about the fate of large logarithms sometimes found in quantum corrections from inflationary particle production.
Article
Astronomy & Astrophysics
Tanguy Grall, Sadra Jazayeri, Enrico Pajer
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2020)
Article
Astronomy & Astrophysics
Daniel Green, Enrico Pajer
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2020)
Article
Astronomy & Astrophysics
Enrico Pajer
Summary: The study focuses on the three-point correlators of gravitons and scalar curvature perturbations around a quasi de Sitter space-time and establishes Bootstrap Rules that fully fix the form of these correlators in the asymptotic future at the boundary. The Boostless Bootstrap approach is shown to account for the breaking of de Sitter boosts caused by inflationary backgrounds. Derivations of bispectra involving gravitons in single-clock, canonical inflation are easily derived in this approach, as well as the scalar bispectrum in the Effective Field Theory of inflation to any order in derivatives. In many cases, the derivations are computationally simpler than the corresponding explicit calculations, emphasizing the implications of locality, vacuum choice, and underlying symmetries.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Physics, Particles & Fields
Enrico Pajer, David Stefanyszyn, Jakub Supel
JOURNAL OF HIGH ENERGY PHYSICS
(2020)
Article
Astronomy & Astrophysics
Harry Goodhew, Sadra Jazayeri, Enrico Pajer
Summary: The study shows that in curved spacetime, unitarity has a significant impact on the relationships between coefficients of the wavefunction of the universe, known as the Cosmological Optical Theorem. This theorem strongly constrains the analytic structure and form of correlators, especially in contact diagrams and four-point exchange diagrams. These results provide a new and powerful tool for bootstrapping cosmological correlators.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Harry Goodhew, Sadra Jazayeri, Mang Hei Gordon Lee, Enrico Pajer
Summary: This paper discusses the initial conditions of the universe and the impact of quantum mechanics on late-time observables, deriving a set of single-cut rules, discussing the analytical structure of the wave function, and verifying the applicability of these rules in some specific examples.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Physics, Particles & Fields
James Bonifacio, Enrico Pajer, Dong-Gang Wang
Summary: Our understanding of quantum correlators in cosmological spacetimes, including those observed in cosmological surveys, has significantly improved in recent years, leading to the derivation of the most general scalar four-point correlator and the extension of the cosmological bootstrap. By applying techniques from commutative algebra, we have been able to derive these results without assuming Lorentz boosts invariance, further building a new connection between flat and curved spacetime physics.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
Sadra Jazayeri, Enrico Pajer, David Stefanyszyn
Summary: In this study, we investigate how final observables can be derived directly from locality, unitarity, and symmetries, without assuming de Sitter boosts. Two new boostless bootstrap tools are introduced to efficiently compute tree-level cosmological correlators/wavefunctions. These tools provide a calculation pipeline without the need for specific assumptions about de Sitter boosts, offering a novel approach to deriving predictions in inflationary cosmology.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Correction
Physics, Particles & Fields
Enrico Pajer, David Stefanyszyn, Jakub Supel
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Particles & Fields
Giovanni Cabass, Enrico Pajer, David Stefanyszyn, Jakub Supel
Summary: By using gravitational interferometers and cosmological observations, we can investigate the laws of gravity in the early universe. To study and interpret the data, it is important to understand the possible non-Gaussianities of gravitons. In this study, the authors derive the most general tree-level expressions for the three-point functions of massless gravitons, assuming scale invariance.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Particles & Fields
Aaron Hillman, Enrico Pajer
Summary: This article presents a new differential representation of the perturbative cosmological wavefunction in de Sitter spacetime. It provides a computational advantage by trading nested bulk time integrals for derivatives on boundary kinematical data. This method is applicable to a wide range of phenomenologically relevant theories.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Particles & Fields
Giovanni Cabass, Sadra Jazayeri, Enrico Pajer, David Stefanyszyn
Summary: We present a set of no-go theorems and yes-go examples for the parity-odd primordial trispectrum of curvature perturbations. Our results show that the presence of scalar fields with arbitrary mass or spinning fields with massless de Sitter mode functions leads to the vanishing of the parity-odd scalar trispectrum and parity-odd scalar correlator. By relaxing certain assumptions, we also provide explicit results for violations of scale invariance, modified dispersion relation, and interactions with massive spinning fields. Our findings demonstrate the sensitivity of the parity-odd trispectrum as a probe for new physics beyond standard inflation.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Physics, Particles & Fields
Santiago Aguei Salcedo, Mang Hei Gordon Lee, Scott Melville, Enrico Pajer
Summary: The wavefunction in quantum field theory is a powerful tool for understanding various aspects of spacetime and boundary observables in different spacetimes. We have investigated the analytic properties of wavefunction coefficients in Minkowski spacetime and found that they are analytic except for singularities on the negative real axis. These singularities are determined by an energy-conservation condition. Our findings have been verified through calculations in scalar field theories, and we have derived new UV/IR sum rules for the wavefunction, which relate the coefficients to integrals of discontinuities in the UV-completion and can constrain total-derivative interactions.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Physics, Particles & Fields
James Bonifacio, Harry Goodhew, Austin Joyce, Enrico Pajer, David Stefanyszyn
Summary: In this study, we compute the tree-level late-time graviton four-point correlation function and quartic wavefunction coefficient for Einstein gravity in de Sitter spacetime. We derive this result using multiple methods, including direct calculation, the in-in formalism, and the wavefunction of the universe. We also find agreement among these different approaches.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Physics, Particles & Fields
Scott Melville, Enrico Pajer
Summary: Research indicates that primordial perturbations in the universe have a quantum origin and can be described by the wavefunction, with unitarity leading to a systematic set of cosmological cutting rules that constrain wavefunction coefficients for different fields and loop orders. These rules have remarkable generality and can be applied to arbitrary interactions of fields with any mass and spin, around a general class of FLRW spacetimes with a Bunch-Davies vacuum. This discovery extends the potential of utilizing unitarity to bootstrap cosmological observables and restrict consistent effective field theories on curved spacetimes.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)