Probing New Physics with Gravitational Waves

25 Jul 2022, 09:00 → 12 Aug 2022, 16:00 Europe/Berlin

02.430 (Mainz Institute for Theoretical Physics, Johannes Gutenberg University)

The detection of gravitational waves gave us a new way to investigate our universe. All signals so far have been of astrophysical origin, and they revealed the existence of unexpected binary systems with remarkably massive black holes. Apart from astrophysical sources, in the future, we will be able to detect also gravitational waves produced in the early universe. Moreover, general relativity and modified theories of gravity can also be tested by their impact on the GW spectrum generated by astrophysical and cosmological sources. Thus, GW astronomy is a unique tool to probe fundamental physics and eventually discover new theories of Nature, with an expected bright future ahead due to the several new GW observatories that will be built in the next decades.

This workshop will gather leading experts in the field of particle physics and cosmology, interested in discussing the new opportunities offered by gravitational waves as probes of new physics. Furthermore, it will be encouraged the participation of experts from the gravitational wave astrophysics community to discuss in-depth astrophysical backgrounds and precise signal predictions. The outcome of this program will be the identification of the most promising new physics scenarios which will be testable and it will help the community in setting the stage for the future development of our field.

Participants.pdf

Monday 25 July

10:00 → 10:30 Coffee

14:15 → 14:30 Introduction

14:30 → 15:15 Gravitational wave background from non-Abelian reheating after axion-like inflation

Speaker: Philipp Klose

Klose.pdf

Tuesday 26 July

10:00 → 10:30 Coffee

10:30 → 11:15 Gravitational Waves from ALP Dark-Photon Systems

Axion-like particles (ALPs) coupled to dark gauge fields can generate a stochastic gravitational wave (GW) background that may be observable by current or future GW observatories. The GWs are sourced by the rapid production of anisotropic stress in the dark photon field due to a tachyonic instability induced by the ALP motion. I provide a brief review of this so-called audible axion mechanism and then present two variations of it. First, I discuss this mechanism within the framework of kinetic misalignment, where the amplitude of the GW spectrum is set by the axion's kinetic energy instead of its decay constant. Then, I consider the relaxion and elaborate how it’s post-inflationary evolution can generate GWs in a similar way.

Speaker: Eric Madge

Madge.pdf

11:15 → 12:00 Universal bounces and thin wall prefactors

Speaker: Miha Nemevšek

Nemevsek.pdf

Nemevsek_notes.pdf

Wednesday 27 July

10:00 → 10:30 Coffee

10:30 → 11:15 Neutron Star Mergers Chirp About Vacuum Energy

Speaker: Gabriele Rigo

Rigo.pdf

19:00 → 22:00 Social Dinner

Goldisch Restaurant: https://www.goldisch.com

Thursday 28 July

10:00 → 10:30 Coffee

10:30 → 11:15 Gauged dark sectors

Speaker: Andrea Tesi

11:15 → 12:00 Probing primordial fluctuations through stochastic gravitational wave background anisotropies

Stochastic gravitational wave backgrounds are expected to be anisotropic. While such anisotropies can be of astrophysical origin, a cosmological component of such anisotropies can carry rich information about primordial perturbations. Focusing on the case of a cosmological phase transition, I will talk about how such anisotropies can give us a powerful probe of primordial non-Gaussianities, complementary to current and future CMB and LSS searches. In the scenario where astrophysical foregrounds are also present, I will then discuss some strategies using which we can extract the cosmological signal, focusing on the case of LISA, Taiji and BBO, in particular.

Speaker: Soubhik Kumar

Kumar.pdf

Friday 29 July

10:00 → 10:30 Coffee

10:30 → 11:15 Probing high and intermediate scale leptogenesis via Gravitational Waves

Speaker: Anish Ghoshal

Monday 1 August

14:30 → 15:15 Probing SUSY-breaking scale with Gws

Speaker: Gongjun Choi

15:15 → 16:00 Model dependence of the GW spectrum of a first order phase transition

Speaker: Jorinde van de Vis

VandeVis.pdf

Tuesday 2 August

10:30 → 11:15 Detectable Gravitational Wave Signals from Inflationary Preheating

I will describe gravitational wave (GW) production during preheating in hybrid inflation models where an axion-like waterfall field couples to Abelian gauge fields. Based on a linear analysis, I will show that the GW signal from such models can be within the reach of a variety of foreseeable GW experiments such as LISA, AEDGE, ET and CE, and is close to that of LIGO A+, both in terms of frequency range and signal strength. Furthermore, the resultant GW signal is helically polarized and thus may distinguish itself from other sources of stochastic GW background. Finally, such models can produce primordial black holes that can compose dark matter and lead to merger events detectable by GW detectors.

Speaker: Evangelos Sfakianakis

11:15 → 12:00 Cosmology Prior to the BBN and its Impact on Gravitational Waves

Speaker: Fazlollah Hajkarim (Goethe University Frankfurt)

fazlollah-hajkarim-talk-august-2-2022-mainz.pdf

Wednesday 3 August

10:30 → 11:15 Prospects of detecting gravitational waves from primordial black holes in axion haloscopes.

Ideas originally developed for axion dark matter can be adopted to search for high-frequency gravitational waves. To illustrate this, I will discuss the Gertsenshtein effect, or the inter-conversion of gravitational waves into electromagnetic waves in the presence of external magnetic (or electric) fields. Exploiting the analogy with axions I will show that axion haloscopes based on lumped-element detectors can probe gravitational waves in the 100 kHz-100 MHz range. Finally, I will discuss the corresponding detection prospects of primordial-black-hole binaries. Based on 2202.00695 (accepted for publication in PRL) and Phys.Rev.Lett. 126 (2021) 2, 021104

Speaker: Camilo Garcia Cely

MTIP_Mainz _GarciaCely.pdf

11:15 → 12:00 Sources and Detection Prospects for GHz Gravitational Waves

The talk will be based on our recent publication https://journals.aps.org/prd/abstract/10.1103/PhysRevD.105.116011 and might also include material of another upcoming publication. I will talk about possible sources in the high frequency regime as well as detection prospects with cavities.

Speaker: Jan Scütte-Engel

HFGWs.pdf

19:00 → 21:00 Dinner

Heiliggeist, Rentengasse 2, 55116 Mainz

Thursday 4 August

10:30 → 11:15 Gravitational Waves from Noninteracting Particles from a First Order Phase Transition

Speaker: Bibhushan Shakya

11:15 → 12:00 Detect the Stochastic Gravitational Wave Background with Pulsar Timing Arrays

Speaker: Xiao Xue

Friday 5 August

10:30 → 11:15 Deformation of the gravitational wave spectrum by density perturbations

In recent years, the possibility of having large density perturbations at high wavenumbers has been actively studied, especially in the study of primordial black holes (PBHs). In this presentation, we point out that such density perturbations affect any pre-existing gravitational wave (GW) spectrum through CMB-like effects. Since GWs produced in the early universe propagate through the density perturbations before reaching the observer, GWs coming from each direction experience different evolution depending on the density perturbations. As a result, the observed (directionally averaged) GWs generally have a deformed spectrum compared to the original one. Therefore, by carefully comparing the observed spectrum with the theoretical GW spectrum at the time of production, we may be able to indirectly observe density perturbations at short scales. In this presentation, we explain how this effect shows up and estimate the maximum expected impact on the GW spectrum, taking into account the latest bound on density perturbations from PBH searches. This talk is based on 2002.11083.

Speaker: Ryusuke Jinno

Jinno.pdf

11:15 → 12:00 GW from Inflation triggered first order phase transition

Speaker: Lian-Tao Wang (University of Chicago)

GW_MITP.pdf

Monday 8 August

14:30 → 15:15 Gravitational mergers of the dark sector neutron stars as the origin of antinuclei hunted by AMS-2

Speaker: Zurab Berezhiani

15:15 → 16:00 TBA

Speaker: Alberto Roper Pol

Tuesday 9 August

10:30 → 11:15 Correlating gravitational wave and gamma-ray signals from primordial black holes

Speaker: Yuhsin Tsai

11:15 → 12:00 TBA

Speaker: Marek Lewiki

Wednesday 10 August

10:30 → 11:15 The gravitational wave echo of dark holograms

Speaker: Nicklas Ramberg

11:15 → 12:00 Gravitational Waves from the Dark Side of the Universe

Speaker: Laura Sagunski

Sagunski.pdf

14:30 → 15:15 A Quantum-Mechanical Mechanism for Reducing the Cosmological Constant

https://arxiv.org/abs/2204.13124

Speaker: Nemanja Kaloper

Kaloper.pdf

19:00 → 21:00 Dinner

Cafe Portugal, Heidelbergerfaßgasse 7, 55116 Mainz

Thursday 11 August

10:30 → 11:15 Primordial gravitational waves boosted by the axion

Speaker: Peera Simakachorn

Simakachorn.pdf

11:15 → 12:00 PTA Searches for Gravitational Waves from Cosmic Strings

Speaker: Kai Schmitz

2022_08_mitp_mainz.pdf

Schmitz.pdf