分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： In pre-recombination early dark energy (EDE) resolutions of the Hubble tension, the rise of Hubble constant value $H_0$ is usually accompanied with the exacerbation of so-called $S_8$ tension. Inspired by the swampland conjecture, we investigate what if a fraction $f_*$ of dark matter is coupled to EDE, $m_{cdm}\sim \exp{(-c{|\Delta\phi_{ede}|\over M_{pl}})}$ with $c\sim {\cal O}(1)$. We perform the MCMC analysis for the relevant EDE models with PlanckCMB, BAO, Pantheon and SH0ES dataset, as well as DES-Y1 data, and find that such a fraction helps to alleviate the $S_8$ tension. However, though $c\gtrsim 0.1$ is allowed for a very small $f_*$, which suggests that a small fraction of dark matter has ever faded with EDE, $c\sim0$ is also consistent.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： In the studies on pre-recombination early dark energy (EDE), the evolution of Universe after recombination is usually regarded as ${\Lambda}CDM$-like, which corresponds that the equation of state of dark energy responsible for current accelerated expansion is $w=-1$. However, in realistic models, $w$ might be evolving. We consider the parametrizations of $w$ with respect to the redshift $z$ in Axion-like EDE and AdS-EDE models, respectively. We performed the Monte Carlo Markov chain analysis with recent cosmological data, and found that the bestfit $w(z)$ is compatible with $w_0=-1,w_a=0$ (the cosmological constant) and the evolution of $w$ is only marginally favored, which so has little effect on lifting the bestfit value of ${H_0}$.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： In pre-recombination early dark energy (EDE) resolutions of the Hubble tension, the rise of Hubble constant value $H_0$ is usually accompanied with the exacerbation of so-called $S_8$ tension. Inspired by the swampland conjecture, we investigate what if a fraction $f_*$ of dark matter is coupled to EDE, $m_{cdm}\sim \exp{(-c{|\Delta\phi_{ede}|\over M_{pl}})}$ with $c\sim {\cal O}(1)$. We perform the MCMC analysis for the relevant EDE models with PlanckCMB, BAO, Pantheon and SH0ES dataset, as well as DES-Y1 data, and find that such a fraction helps to alleviate the $S_8$ tension. However, though $c\gtrsim 0.1$ is allowed for a very small $f_*$, which suggests that a small fraction of dark matter has ever faded with EDE, $c\sim0$ is also consistent.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
Qifeng Ruan
Wang Zhang
Hao Wang
John You En Chan
Hongtao Wang
Hailong Liu
Dianyuan Fan
Ying Li
Cheng-Wei Qiu
Joel K. W. Yang
摘要： Colour changes can be achieved by straining photonic crystals or gratings embedded in stretchable materials. However, the multiple repeat units and the need for a volumetric assembly of nanostructures limit the density of information content. Inspired by surface reliefs on oracle bones and music records as means of information archival, here we endow surface-relief elastomers with multiple sets of information that are accessible by mechanical straining along in-plane axes. Distinct from Bragg diffraction effects from periodic structures, we report trenches that generate colour due to variations in trench depth, enabling individual trench segments to support a single colour. Using 3D printed cuboids, we replicated trenches of varying geometric parameters in elastomers. These parameters determine the initial colour (or lack thereof), the response to capillary forces, and the appearance when strained along or across the trenches. Strain induces modulation in trench depth or the opening and closure of a trench, resulting in surface reliefs with up to six distinct states, and an initially featureless surface that reveals two distinct images when stretched along different axes. The highly reversible structural colours are promising in optical data archival, anti-counterfeiting, and strain-sensing applications.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： We propose a novel intensity diffraction tomography (IDT) reconstruction algorithm based on the split-step non-paraxial (SSNP) model for recovering the 3D refractive index (RI) distribution of multiple-scattering biological samples. High-quality IDT reconstruction requires high-angle illumination to encode both low- and high- spatial frequency information of the 3D biological sample. We show that our SSNP model can more accurately compute multiple scattering from high-angle illumination compared to paraxial approximation-based multiple-scattering models. We apply this SSNP model to both sequential and multiplexed IDT techniques. We develop a unified reconstruction algorithm for both IDT modalities that is highly computationally efficient and is implemented by a modular automatic differentiation framework. We demonstrate the capability of our reconstruction algorithm on both weakly scattering buccal epithelial cells and strongly scattering live $\textit{C. elegans}$ worms and live $\textit{C. elegans}$ embryos.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： Benefiting from their low-loss light manipulation at subwavelength scales, optically resonant dielectric nanostructures have emerged as one of the most promising nanophotonic building blocks. Here, we theoretically conceive a dielectric nanocavity made of moderate-refractive-index gallium nitride and investigate the strong electromagnetic field confinement inside the nanocavity. We demonstrate that gallium nitride nanodisks can support anapole states, which result from interference between electric dipole and toroidal dipole modes and are tunable by changing sizes of the nanodisks. The highly confined electromagnetic field of the anapole states can promote the emission efficiency of a single quantum emitter inside the nanocavity. Moreover, the emission polarization can be tuned by placing the quantum emitter off the nanodisk center. Our findings provide a promising candidate for the construction of ultra-compact, super-radiative integrated quantum light sources.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： We propose and generate a new class of structured light fulfilling quantum-like coherent states based on a set of circular Airy vortex modes. Such coherent-state wave packets possess strong focus with both radial and angular self-accelerations, which exploit more general 3D inhomogeneous velocity control with global spatial symmetry of multilayer rotation akin to galactic kinematics, as termed galaxy waves. Galaxy waves are endowed with new degrees of freedom to control strong focusing and acceleration of 3D structured light, promising numerous applications in optical trapping, manufacturing, and nonlinear optics.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
Hongtao Wang
Hao Wang
Qifeng Ruan
John You En Chan
Wang Zhang
Hailong Liu
Soroosh Daqiqeh Rezaei
Jonathan Trisno
Cheng-Wei Qiu
Min Gu
Joel K. W. Yang
摘要： The orbital angular momentum (OAM) of light holds great promise for applications in optical communication, super-resolution imaging, and high-dimensional quantum computing. However, the spatio-temporal coherence of the light source has been essential for generating OAM beams, as incoherent ambient light would result in polychromatic and obscured OAM beams in the visible spectrum. Here, we extend the applications of OAM to ambient lighting conditions. By miniaturizing spiral phase plates and integrating them with structural color filters, we achieve spatio-temporal coherence using only an incoherent white light source. These optical elements act as building blocks that encode both color and OAM information in the form of colorful optical vortices. Thus, pairs of transparent substrates that contain matching positions of these vortices constitute a reciprocal optical lock and key system. Due to the multiple helical eigenstates of OAM, the pairwise coupling can be further extended to form a one-to-many matching and validation scheme. Generating and decoding colorful optical vortices with broadband white light could find potential applications in anti-counterfeiting, optical metrology, high-capacity optical encryption, and on-chip 3D photonic devices.
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