Reconstruction of power spectrum of primordial curvature perturbations on small scales from primordial black hole binaries scenario of LIGO/VIRGO detection

As a candidate bound for the Binary Black Hole(BBH) merger events detected by LIGO/Virgo, Primordial Black Holes(PBHs)provide a useful tool to investigate the primordial curvature perturbations on small scales. Using the GWTC-1 to GWTC-3 catalogs, under the scenario that PBHs originate from large primordial curvature perturbations on small scales during infiationary epoch, we for the first time reconstruct the power spectrum of primordial curvature perturbations on small scales. It is found that the value of the amplitude of the primordial power spectrum is enhanced to O(10-2)on scales O(1) pc. This may imply the validity of PBH as a possible BBH merger candidate.

Exploring cosmic origins through primordial black hole mass functions

Primordial black holes(PBHs)are objects formed from early universe density fluctuations,offering insights into the universe's infancy.The PBH mass function characterizes their mass distribution,which is crucial for understanding their role in shaping various structures[1].Typically,the focus of various studies is on the mass function of supermassive black holes(SMBHs),which originate due to unknown mechanics.However,PBHs can serve as the seeds for SMBHs owing to their extensive mass range and long lifetime.Therefore,the physics of the early universe may have left imprints on the SMBH properties via these massive PBH seeds.

Defining Local Heritages in Preserving Modern Shanghai Architecture

The notion that local heritage can be defined by the‘collective memory’of a city may be considered as being simplistic nowadays.Heritage is increasingly recognised as knowledge,a cultural product or even a political resource set within specific social circumstances.The local heritage underpins various ways of relating our past with our present and future,which are often much more complicated than we can imagine.The evolution of the conser­vation of Shanghai’s modern heritage architecture shows this complexity.By tracing more than 50 years’progress in historic preservation,this paper shows how historical buildings from Shanghai’s early modern period were selected as urban heritage in the changing socio-political contexts of different time periods.Starting with how the first mod­ern buildings were listed in a new Chinese narrative in the 1950s,this paper focuses on the great ideological changes and progress Shanghai achieved after China’s reform and opening policy since the 1980s.Emphasising the great significance of the establishment of local legislation for historic preservation as an extension of the national system,examples of the great enrichment of Shanghai’s local heritage are presented through multiple narratives and inter­pretations of Shanghai’s modern history.In a deeper observation of various practices and complicated contradic­tions,the historic preservation of Shanghai’s modern heritage architecture is shown to be a process of continuing to reconstruct the relationships between city and the State,the city and the world,as well as the city's past,present and future in a pluralist society.