Conveners
Gravitational Waves: parallel session 3
- KeJia Lee (Peking univerisity)
Gravitational Waves: parallel session 4
- Jun Zhang (University of Chinese Academy of Sciences)
Gravitational Waves: parallel session 5
- Alba Romero-Rodriguez (Laboratoire D'Annecy de Physique de Particules (LAPP))
Gravitational Waves: parallel session 6
- Huaike Guo (ไธญๅฝ็งๅญฆ้ขๅคงๅญฆ๏ผICTP-AP๏ผ)
Gravitational Waves: parallel session 7
- Yiqiu Ma
Gravitational Waves: parallel session 8
- Bram Slagmolen
Gravitational wave (GW) observations offer a powerful tool for testing the fundamental Lorentz and parity symmetries of gravity. Any violation of these symmetries could manifest as deviations in GW propagation. In this talk, I will explore how current and future GW detections can constrain Lorentz- and parity-violating effects in gravity. I will introduce a systematic parameterization...
Wave effects are a crucial aspect of gravitational waves. When the wavelength of GWs is comparable to or greater than the Schwarzschild radius of an object, the propagation of gravitational waves no longer follows geometrical optics, and coherence and interference can occur. Despite their significance, studying these wave effects can be challenging due to their complexity.
In this talk, I...
Gravitational wave (GW) birefringence is a remarkable phenomenon which provides a window to test partiy violation in gravity. In this talk, I would discuss our recent studies on the GW birefringence in the FDM and symmetron models. In particular, inspired by the complicated distributions of the Fuzzy dark matter (FDM) and the symmetron field in our Galaxy, we are led to considering the GW...
Since the first direct detection to the gravitational wave (GW), i.e., the event GW150914, it has emerged as a blockbuster during the past decade within the realm of theoretical physics. Specially, it provides us with an unprecedented opportunity in testing theories of gravity that beyond the scope of general relativity (GR), especially in the strong-field regime. One common way for extracting...
Advances in gravitational wave detection offer a new approach to probing the very early history of the Universe and the corresponding fundamental physics models. They can provide crucial insights into topics such as symmetry breaking, gravitational theories, and the origin of dark matter. This presentation will briefly introduce and summarize the primary sources of gravitational waves,...
Dark matter makes up most of the matter in the universe, yet its true nature remains unknown. Gravitational wave observations open up new opportunities to search for dark matter in ways not possible before. In this talk, I will present two efforts to explore dark matter using both ground- and space-based gravitational wave detectors. First, I will introduce searches for planetary-mass compact...
If particle dark matter (DM) and primordial black holes (PBHs) coexist, PBHs will be surrounded by particle DM, forming celestial objects known as dressed PBHs (dPBHs). These structures suggest a scenario in which PBHs and DM can exist simultaneously. However, in the high-frequency regime, the gravitational lensing effect of bare PBHs is similar to that of dPBHs. Ground-based gravitational...
Strange-quark matter (SQM) may be the true ground state of hadronic matter, indicating that the observed pulsars may actually be strange stars (SSs), but not neutron stars. According to the SQM hypothesis, the existence of a hydrostatically stable sequence of SQM stars has been predicted, ranging from 1 to 2 solar mass SSs, to smaller strange dwarfs and even strange planets. While...
The upcoming era of gravitational wave (GW) astronomy heralds unprecedented opportunities to study compact binaries, in particular double neutron stars (DNS), double white dwarfs (DWD), and binary black holes, through their gravitational waves, providing important insights into binary evolution, NS physics, and the overarching architecture of the universe. In this talk, I will give an overview...
Supernovae are very promising multi-messenger astronomical targets. They emit electron-magnetic waves, neutrinos, gravitatinal waves and maybe beyond-standard model particles like axions.
Neutrinos are deeply involved in the mechanism of supernova explosions, which have been investigated along with the development of neutrino radiation transport. Gravitational waves are emitted from...
Gravitational waves can exhibit complex features in various scenarios, such as orbital eccentricity, gravitational lensing, and the presence of higher-order modes. These effects are especially relevant for next-generation gravitational wave detectors, which will have the sensitivity to capture such rich signal structures. In this talk, I will present our recent work on leveraging these complex...
The first detection of a gravitational-wave (GW) signal in 2015 have opened a new observational window to probe the universe. This probe can not only reveal previously inaccessible binaries, black holes, and other compact objects, but also can detect exoplanets through their imprint on GW signals, thereby significantly extend current exoplanet surveys. To date, nearly 6 000 exoplanets have...
Preheating stage after inflation can cause a significant effect of graviton production. These gravitons at high frequencies can contribute to the dark radiation component which is constrained from CMB data. Gravitons at lower frequencies would produce an inevitable stochastic gravitational wave background which may be probed in future ground-based and space-based detectors. We show that out of...
The gravitational wave background (GWB) is a superposition of weak, independent and unresolved gravitational wave (GW) sources. It can be sourced by both astrophysical and cosmological sources, among which we find unresolved compact binary coalescences, supernovae, first order cosmological phase transitions and cosmic strings. Since the beginning of its observational runs, the LIGO-Virgo-KAGRA...
The data analysis of future space-based gravitational wave detectors like LISA and Taiji face significant challenges due to non-stationarities in their data, originating from time-varying astrophysical confusion foregrounds and instrumental noise drifts, which compromise traditional Fourier-domain analysis methods. In this work, we address this challenge by proposing a unified formalism based...
Gravitational wave data analysis (GWDA) faces significant challenges due to high-dimensional parameter spaces and non-Gaussian, non-stationary artifacts in the interferometer background, which traditional methods have made significant progress in addressing but continue to face limitations. Artificial intelligence (AI), particularly deep learning (DL) algorithms, offers potential advantages,...
title:Accelerating Stochastic Gravitational Wave Backgrounds
Parameter Estimation in Pulsar Timing Arrays with Flow Matching
abstract:Pulsar timing arrays (PTAs) are essential tools for detecting the stochastic gravitational wave background (SGWB), but their analysis faces significant computational challenges. Traditional methods like Markov-chain Monte Carlo (MCMC) struggle with...
We systematically investigate the impact of source confusion on parameter estimation for massive black hole binaries (MBHBs) in the context of the Taiji space-based gravitational wave mission. Source confusion, arises from simultaneous overlap of signals in both time and frequency domains, can degrade the accuracy of parameter recovery. To assess this effect, we simulate MBHB populations using...
KAGRA gravitational wave telescope in Japan started the 4th international gravitational wave observation(O4) with Advanced-LIGO and Advanced Virgo in May 2023, after repairs, upgrades, and commissioning for 3 years from May 2020. Under the LIGO-Virgo-KAGRA(LVK) O4 scenario, KAGRA restarted its commissioning from July 2023 to upgrade and improve its sensitivity and to rejoin O4 around Spring...
We present a number of new techniques to utilize a phase-sensitive amplifier to effectively reduce an optical loss in the output readout chain.
Quantum entanglement has recently begun to play an increasingly important role in astrophysical observations. Innovative techniques such as quantum steering, entanglement swapping, and quantum teleportation are opening new possibilities for precision measurements that surpass classical limits.
In this presentation, we provide a theoretical overview of how quantum entanglement can be applied...
We investigate the sensitivity and performance of space-based Optical Lattice Clocks (OLCs) in detecting gravitational waves, in particular the Stochastic Gravitational Wave Background (SGWB) at low frequencies $(10^{-4}, 1) \rm Hz$, which are inaccessible to ground-based detectors. We first analyze the response characteristics of a single OLC detector for SGWB detection and compare its...
The ultrahigh-frequency (above 10 kHz) gravitational waves (GW) window provides a unique opportunity to detect primordial GWs, free from astrophysical foregrounds that dominate lower frequencies. A stochastic GW background in this range is generically predicted from cosmological phase transitions and topological defects associated with grand unification and other ultra-high energy theories. We...
Since the WIMP dark matter from the freeze-out mechanism is not favored by current dark matter direct search, we explore new dark matter production mechanism and the possible gravitational wave signals.
Recent observations by pulsar timing arrays (PTAs) such as NANOGrav, EPTA, PPTA, and CPTA suggest the presence of nanohertz stochastic gravitational wave background (GWB), which may be a hint for new physics. Among several possible sources, those from metastable cosmic string would be attractive since the spectral tilt of the GWB can be easily consistent with those suggested in PTAs. However,...
The properties of the stochastic gravitational wave background are crucial for our understanding of cosmic evolution. With the release of data from major pulsar timing arrays, the existence of an extremely low-frequency stochastic gravitational wave background has been widely acknowledged. In this work, based on the theory of general relativity and stochastic dynamics, we have established the...
This presentation explores the detection and analysis of stochastic gravitational wave backgrounds (SGWB) originating from first-order cosmological phase transitions, with a focus on the sound wave contributions. It begins by introducing the relevant detector configurations, including space-based interferometers like LISA and Taiji, and the construction of AET channels to extract clean...
Seismic noise in both translational and angular degree-of-freedom poses significant challenges to high-precision measurements. To mitigate low-frequency seismic noise coupling, active vibration isolation platforms have been developed, with the combination of low-noise and single or multiple degree-of-freedom seismometers play a critical role. This paper presents the design and performance...
Pulsar timing arrays (PTAs) have emerged as powerful tools for constraining modified theories of gravity through the detection and characterization of nanohertz gravitational waves, with recent observations from major collaborations (NANOGrav, PPTA, EPTA, InPTA, CPTA, and MPTA) revealing evidence for a stochastic gravitational wave background. This talk presents comprehensive constraints on...
