‘t Hooft, Gerard (Utrecht U)    https://www.uu.nl/en/research/prof-dr-gerard-t-hooft 

"Quantum Clones in the Interior of a Black Hole"

Ashtekar, Abhay (Penn State U)   https://science.psu.edu/physics/people/abhay-ashtekar 

"Enigma of Black Hole Horizon" 

Cai, Rong-Gen (ITP Beijing)     http://sourcedb.itp.cas.cn/yw/zjrck/cm/201804/t20180424_5001122.html 

"QCD critical Point and Induced Gravitational Wave by Black Hole Physics" 

We build a holographic model of QCD matter at finite baryon chemical potential and finite temperature. Fixing all model parameters by use of the state-of-the-art lattice QCD data at zero chemical potential, the predicted equations of state and QCD trace anomaly relation are in quantitative agreement with the latest lattice results. We then give the exact location of the critical endpoint as well as the first-order transition line, which is within the coverage of many upcoming experimental measurements. Moreover, using the data from our model at finite baryon chemical potential, we calculate the spectrum of the stochastic gravitational wave background associated with the first-order QCD transition in the early universe, which could be observable via pulsar timing array in the future.

Chen, Chiang-Mei (Natl Central U, Taiwan)    https://scholars.ncu.edu.tw/en/persons/chiang-mei-chen

           "Quantum Improved Black Holes in Asymptotically Safe Gravity"

In this talk, I will discuss the quantum improvement of black hole solutions in the context of asymptotic safety. The Newton coupling in this formulation depends on an energy scale, which must be identified with some length scale in order to study physical consequences to black holes. We propose that the consistency of the first law of thermodynamics is the principle that should determine physically sensible scale identification, at least close to the horizon. I will discuss some interesting physical consequences, such as the phase structure of the quantum improved black holes. 

Cho, Yongmin (SNU)    https://prabook.com/web/yongmin.cho/437045

"Cosmological Implication of Electroweak Monopole" 

We discuss the physical implications, in particular the cosmological im[plications, of the electroweak monopole. As the only stable heavy particle in the early universe, it could become the seed of the primordial blackholes, the large scale structure of the universe, and source of the intergalactic magnetic field. Moreover, there are enough remnant monopoles in the present universe which can be detected. Most importantly, it generates the magnetic current, and becomes the topological avatar of the new physics. 

De Laurentis, Mariafelicia (U Napoli)   https://www.docenti.unina.it/mariafelicia.delaurentis 

"Imaging Black Holes with EHT" 

The Event Horizon Telescope has presented the first images of the shadows of the black holes in the Milky Way and in the M87 galaxy. The observed radiation has originated in two of the strongest gravitational fields found in the Universe, encoding during their travel to the Earth the properties of the black-hole spacetimes. In this talk, I'll give a rundown of the scientific process, imaging analysis, and theoretical explanation that led to the release of the first EHT images of supermassive black holes. 

Freedman, Wendy (U Chicago)     https://astrophysics.uchicago.edu/people/profile/wendy-l.-freedman/

"Cosmological Implications of James Webb" 

The question of whether there is new physics beyond our current standard model, Lambda Cold Dark Matter (LCDM), is a crucial unresolved issue in cosmology today. Recent measurements of the Hubble constant (Ho) using Cepheids and Type Ia supernovae (SNe) appear to differ significantly (5-sigma) from values inferred from the cosmic microwave background (CMB) fluctuations. This discrepancy, if real, could indicate new physics beyond the standard model. In this talk, I will review results using data from the Hubble Space Telescope using Cepheids as well as the Tip of the Red Giant Branch (TRGB). A comparison of these results indicates that there remain systematic uncertainties in the local calibration of Ho. I will describe a new program using the James Webb Space Telescope (JWST) aimed at reducing uncertainties in extragalactic distances and the measurement of Ho, and present some new, preliminary results. JWST has four times the resolution and ten times the sensitivity of HST in the near infrared, and will be critical for ascertaining whether new physics is required beyond the standard model of cosmology. 

Giani, Leonardo (U Queensland)     https://smp.uq.edu.au/profile/10412/leonardo-giani 

"Concordance model and cosmic tensions: The gravity of the situation"

Whilst these tensions might be individually attributed to unaccounted experimental systematics, it is unavoidable (and tempting) to consider the possibility that they collectively hint towards new physics beyond LCDM. In this talk, I will briefly review the evidence for a physical interpretation of these tensions and explore their possible interplay. I will also provide a bird-eye view of the most studied strategies to solve or alleviate (some of) these tensions. Finally, I will speculate on these tensions' impact on our current understanding of the Universe and the gravitational interaction. 

Im, Myungshin (SNU Seoul)    http://astro.snu.ac.kr/~mim/ 

"7-dimensional Telescope for Multi-messenger Astronomy" 

The 2017 detection of the binary neutron star (BNS) merger event in both gravitational wave (GW) and electromagnetic wave (EM), GW170817, has shown the great potential for multi-messenger astronomy, allowing us to understand the link between neutron star mergers and gamma-ray bursts, physical mechanisms and environments of the EM counterpart, kilonova (KN), and cosmology with GW sources. Yet, GW170817 is still the only GW event for which MMA was possible. With the start of the LVK O4 run in May 2023, the situation is now changing. The forecast is about 10 BNS merger event detections during O4, with many of them having a GW localization accuracy on par with GW170817. To capitalize on the anticipated GW source discoveries, we have prepared an optical EM follow-up network of telescopes named the Gravitational-wave EM Counterpart Korean Observatory (GECKO). In particular, we are now constructing a new facility, the 7-Dimensional Telescope (7DT) in Chile for multi-messenger astronomy. 7DT is a multiple-telescope system that can perform spectral mapping over a wide field of view (> 1 deg2) and will be efficient in catching KNe associated with future GW events. A partial system of 7DT started operation. In this talk, we will outline the current challenges of optical/NIR counterpart observations for the KNe discovery and outline our past GW optical follow-up activities. Then we will introduce 7DT and our observing strategy as well as early results using the telescope. 

Kanno, Sugumi  (Kyushu U)    https://hyoka.ofc.kyushu-u.ac.jp/search/details/K007644/english.html

"Towards the Detection of Nonclassical Primordial Gravitational Waves"

One of the cornerstones of inflationary cosmology is that the large scale structure of the Universe has a quantum mechanical origin. This invites the question of whether compelling observational evidence for the quantum nature of the origin can be found. Primordial gravitational waves are generated directly from quantum fluctuations during inflation. Since they interact with matter very weakly, travel through the Universe virtually unimpeded, it is expected that they keep their nonclassicality until today. In this talk, I will present some methods to clarify whether the universe has a quantum mechanical origin by detecting the nonclassical primordial gravitational waves. 

Kim, Chunglee  (Ewha W U)    https://pure.ewha.ac.kr/en/persons/chunglee-kim

"The black hole astrophysics in the era of multi-messenger astronomy"

The 21C has been a golden era of black hole astrophysics. Existence of stellar-mass black hole binaries were confirmed by gravitational-wave observations. The images of supermassive black holes at the center of galaxies were taken by the frontier technique of radio interferometry. Recent observations play a crucial role to improve our understanding of black holes. With upgrades of existing facilities and R&D to establish better, powerful instruments, more discoveries and surprises are expected. In this plenary talk, I will give an overview on the recent progress in black hole astrophysics mainly based on observations. I will also discuss some of the big questions to be answered in the context of black hole astrophysics. 

Kiuchi, Kenta  (AEI Potsdam)     https://www.aei.mpg.de/person/97837

"Numerical Relativity in Multi-messenger Era"  

Since the first observation of GW170817, AT2017gfo, and GRB170817A, there is no doubt that the binary neutron stars will continue playing a leading role in the multimessenger astronomy era. A precise numerical relativity simulation implementing the effects of all the fundamental interactions is the chosen way to theoretically predict and interpret binary neutron star mergers. In this talk, I will discuss the current status of our understanding of binary neutron star mergers and introduce a cutting-edge simulation result.

Laemmerzahl, Claus (U Bremen)    https://www.zarm.uni-bremen.de/en/research/space-science/claus-laemmerzahl.html

"Gravitomagnetism and Experiments" 

Lobo, Francisco S. N.  (U Lisbon, Portugal)   https://ciencias.ulisboa.pt/perfil/fslobo 

"Beyond Einstein’s General Relativity: Hybrid metric-Palatini gravity and curvature-matter couplings" 

Einstein's General Relativity (GR) is possibly one of the greatest intellectual achievements ever conceived by the human mind. In fact, over the last century, GR has proven to be an extremely successful theory, with a well established experimental footing. However, the discovery of the late-time cosmic acceleration, which represents a new imbalance in the governing gravitational field equations, has forced theorists and experimentalists to question whether GR is the correct relativistic theory of gravitation, and has spurred much research in modified gravity, where extensions of the Hilbert-Einstein action describe the gravitational field. In this talk, we perform a detailed theoretical and phenomenological analysis of two largely explored extensions of f(R) gravity, namely: (i) the hybrid metric-Palatini theory; (ii) and modified gravity with curvature-matter couplings. Relative to the former, it has been established that both metric and Palatini versions of f(R) gravity possess interesting features but also manifest severe drawbacks. A hybrid combination, containing elements from both of these formalisms, turns out to be very successful in accounting for the observed phenomenology and avoids some drawbacks of the original approaches. Relative to the curvature-matter coupling theories, these offer interesting extensions of f(R) gravity, where the explicit nonminimal couplings between an arbitrary function of the scalar curvature R and the Lagrangian density of matter, induces a non-vanishing covariant derivative of the energy-momentum tensor. We explore both theories in a plethora of applications, namely, the weak-field limit, cosmology, and the irreversible matter creation processes of a specific curvature-matter coupling theory. 

Luo, Jun (SYS U Zhuhai)   https://www.sysu.edu.cn/sysuen/info/1911/25512.htm

"TianQin: the Chinese mission to detect gravitational waves in space" 

TianQin is a space-based gravitational wave (GW) detector expected to launch around 2035. It will detect GWs in the frequency band 0.1 mHz~1 Hz, offering the chance to detect GWs from a large variety of sources, such as massive black holes, stellar mass black holes, Galactic compact binaries, and so on. The mission was officially proposed in 2014 and has passed a couple of its main milestones. In this talk, I will introduce the mission and the main progress that has been made. 

Pinfold, James (U Alberta)    https://apps.ualberta.ca/directory/person/jpinfold

"Blue Sky Physics with Dedicated Detectors at the LHC" 

The MoEDAL experiment, the first dedicated search experiment at the LHC, took data at LHC's Run-1/2. It was focussed on the quest for highly ionizing avatars of new physics. At LHC's' Run-3. the upgraded MoEDAL-MAPP experiment has an enhanced reach for physics beyond the Standard Model that includes sensitvity to highly ionizing, feebly ionizing, and, very long-lived particle messengers of new physics. MoEDAL-MAPP has now been joined at Run-3 by the FASER and MILLIQAN. experiments. Concentrating on MoEDAL-MAPP we will discuss all of these new dedicated search experiments and their physics horizons, in arenas that have cosmological implications., such as the search for dark matter. 

Rossi, Elena (Leiden U)   https://home.strw.leidenuniv.nl/~emr/

"Pioneering science with the Laser Interferometer Space Antenna" 

Ruffini, Remo (ICRA)     http://www.icra.it/People/Ruffini.htm

"GRB220101A the most powerful GRB with seven BdHN Episodes observed" 

A long GRB that occurred at 2022-01-01 05:11:13 (UT), was triggered by multiple satellites, including Swift (Tohuvavohu et al. 2022), Fermi (Arimoto et al. 2022), AGILE (Ursi et al. 2022), and Konus-Wind (Tsvetkova et al. 2022). The optical observation by Xinglong-2. 16m telescope (Fu et al. 2022) revealed a broad absorption feature in the spectrum indicating the presence of Lyman alpha absorption, as well as from the absorption lines, the redshift was determined to be z=4.61, which was confirmed by the Liverpool tlescope (Perley 2022) and NOT (Fynbo et al. 2022). The burst exhibited a bright, complex multi-peaked time profile within the first ~ 150s.  An estimated isotropic equivalent energy is of E_iso ~ 4x10^54 erg, and a peak luminosity is of L_p ~ 9x10^53 erg s^(-1), making GRB 220101A as one of the most luminous GRBs ever observed. The fact that it occurs at z=4.6 gives a great opportunity to exploit new perspectives of observations as presented in Bianco et al. 2023. The discovery of a radio source with a mean frequency of 6.0 GHz was reported in Laskar (2022a). This finding aligns with the X-ray position noted in Osborne et al. (2022), as well as the optical positions reported by Tohuvavohu et al. (2022) and Hentunen et al. (2022), along with the mm-band position mentioned in Laskar (2022b). All seven episodes characterizing a BdHN I, as predicted in Ruffini et al. (2022a,b), have been identified, details are presented in Ruffini et al., (submitted). Our attention in this article is to identify the earliest XRT observations meade possible by the use of the cosmological redshift of z = 4.61 and to obtain an unprecedented accurate description of the rising part and the power-law decay part of the X-ray emission evidencing the transition from a Jacobi ellipsoid into a Mac Laurin spheroid in  the description of the newNS originating the afterglow.  

Sabbi, Elena (STScI)   https://www.stsci.edu/~sabbi/

"From the solar system to the first galaxies: how JWST is revolutionizing our view of the Universe" 

Since the beginning of science operation just one year ago, the James Webb Space Telescope (JWST) has ushered in a new era in astronomy. In this talk, I will provide an overview of the remarkable journey that has brought us to this point, highlighting the telescope's design, instrument capabilities, launch, and commissioning process. I will then delve into the astonishing results already achieved by JWST and explore their implications for our understanding of the Universe in the years to come. With its unparalleled capabilities, JWST promises to revolutionize our view of the cosmos, shaping the course of astronomy in the decades to come. JWST’s advanced technologies and innovative design allow it to capture stunningly sharp images and gather exquisite spectra from solar system planets to embedded star-forming regions to the first galaxies across a wide range of wavelengths. I will discuss how JWST’s preliminary results are revolutionizing our understanding of the formation and evolution of stars and planets and challenging our view of the Universe’s evolution. 

Sasaki, Misao (IPMU Tokyo)     https://db.ipmu.jp/member/personal/566en.html 

"Cosmology of Primordial Black Holes and Gravitational Waves"  

After briefly reviewing what primordial black holes are and how they may have formed in the early universe, some recent topics will be discussed in particular in the context of gravitational wave cosmology. 

Shoemaker, David (MIT)   https://space.mit.edu/people/shoemaker-david-h/ 

"Present and Future Terrestrial GW Detectors-LIGO, ET, and CE" 

The present network of terrestrial laser interferometric gravitational-wave detectors have demonstrated the initial possibilities for GW observational science, both stand-alone and multi-messenger. The network of LIGO, Virgo, and KAGRA has recently started its O4 observing run with higher sensitivity. Activities are underway for refinements of the current detectors to reach design sensitivity in an O5 run in the late 2020's. More aggressive rework is in planning for a final upgrade of the instruments to be operational in the early 2030's.. Then, on the longer timescale, Cosmic Explorer and Einstein Telescope are US and European proposals to build new infrastructures with longer baselines, offering a factor of 10 improvement over the current instruments. These new observatories could be on line by mid-2030. 

Starobinsky, Alexei (Landau Inst Moscow)    https://www.itp.ac.ru/en/persons/starobinsky-aleksei-aleksandrovich/

"Generating Peaks and Troughs in Primordial Perturbation Spectra" 

At the present state-of-the-art, the simplest inflationary models, based either on scalar fields in General Relativity or on modified f(R) gravity, which produce the best fit to all existing observational data, require only one dimensionless parameter to be taken from observations. These models include the pioneer R+R² (Starobinsky) one, the Higgs model, and the mixed R²-Higgs model which has been shown to be effectively one-parameter, too. They predict scale-free and close to scale-invariant power spectra of primordial scalar perturbations and gravitational waves generated during inflation. Their target prediction for the tensor-to-scalar ratio is r=3(1-n_s)^2 = 0.004, that is still about one order of magnitude less than the present upper bound. Still future observations, in particular the discovery of primordial black holes, may prove that the primordial scalar power spectrum has additional local peaks and troughs what requires at least two new phenomenological parameters. I discuss mechanisms to produce such features including the recently proposed one which arise in many-field inflation with a large non-minimal kinetic term of an inflaton field leaving inflation before its end. In this case, in addition to PBHs, large peaks in the primordial tensor perturbation spectrum at small scales are generated in the second order of scalar perturbations. As for local non-scale-free features at cosmological scales suggested by features in the CMB temperature anisotropy for l = 2 and in the range l = 20-30, the existing CMB data including CMB polarization do not favor them, but are not able to exclude them completely.

Sushkov, Sergey (Kazan FU)   https://kpfu.ru/Sergey.Sushkov?p_lang=2

"Anisotropic Horndeski Cosmology" 

In this talk we will discuss the most general scalar-tensor theories of gravity which contain the only single scalar degree of freedom. These theories, known as Degenerate Higher-Order ScalarTensor (DHOST) theories, include Horndeski and Beyond Horndeski theories. More details, we will focus on the particular subclass of models, known as the theory of gravity with non-minimal derivative coupling, and consider isotropic and anisotropic cosmological models in such the theory. As well, we will shortly discuss compact astrophysical objects (black holes, wormholes, neutron stars) in the theory of gravity with non-minimal derivative coupling. 

Wiltshire, David (U Canterbury)    https://www.canterbury.ac.nz/science/contact-us/people/david-wiltshire.html 

"Cosmic expansion versus motion: Probing the difference" 

Winstanley, Elizabeth (U Sheffield)     https://www.sheffield.ac.uk/maths/people/academic/elizabeth-winstanley 

"Quantum Effects outside and inside Black Holes"  

We review some recent developments in quantum field theory on black hole space-times, both outside and inside the event horizon. The renormalized expectation value of the stress energy tensor (RSET) is an object of central importance as it governs the backreaction of the quantum field on the space-time geometry, but calculating the RSET on black hole space-times is far from trivial. The original methodology was developed in the 1980s and 1990s and successfully applied to a range of quantum fields on four-dimensional Schwarzschild black holes. The subject has enjoyed a renaissance in recent years with the development of novel approaches to computing the RSET and renormalized vacuum polarization (VP). These advances have enabled calculations on a wider range of black hole space-times to be performed and new physics questions to be addressed. In this talk we will discuss some recent results for the RSET and VP on a range of black hole backgrounds to give a flavour of the insights to be gained into the quantum properties of black holes both outside and inside the event horizon. 

Yoon, Jonghyuk  (Konkuk U) 

"Hamiltonian Reduction of Einstein’s Theory without Isometry"

A mathematical prescription of a complete Hamiltonian reduction using (2+2) Hamiltonian formalism of Einstein's gravity without isometry is presented. The area of a cross-section of an out-going null hypersurface is chosen as the privileged time coordinate, and the privileged spatial coordinates are chosen as the coordinates of (and on) equipotential surfaces of a certain function on the gravational phase space. In the privileged coordinates, all the constraints are solved completely, and gravitational Hamiltonian and momentum densities are expressed as local functions of physical degrees of freedom. The logarithm of the 4 volume element of spacetime metric in the privileged coordinates turns out to be a superpotential, whose gradient is the energy-momentum 4 vector of physical Hamiltonian and momentum densities. The Hamilton's equations of motion obtained through Hamiltonian reduction agree with Einstein's equations in the privileged coordinates. This work is a generalization of Hamitonian reduction of Einstein's theory with two Killing vector fields by K. Kuchar to spacetimes without isometry.