Conveners
Gravity & Gravitational Waves: GW and Particle Cosmology
- Navin McGinnis (Arizona university)
Gravity & Gravitational Waves: Gravity and GW Phenomenology
- Tinatin Kakhniashvili
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Tina Kahniashvili (CMU (USA) and IliaUni (Georgia))15/05/2024, 14:00Gravity & Gravitational Waves
Recently, NANOGrav collaboration (based on 12.5 years of observation) reported strong evidence [Arzoumanian et al. (2020)] and later, the analysis of 15 years of data resulted in confirming the detection of a stochastic gravitational wave background [Agazie et al. (2023)] that can be understood, along with the possibility of the astrophysical sources (such as supermassive black holes) induced...
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Fazlollah Hajkarim (University of Oklahoma)15/05/2024, 14:15Gravity & Gravitational Waves
We analyse sound waves arising from a cosmic phase transition where the full velocity profile is taken into account as an explanation for the gravitational wave spectrum observed by multiple pulsar timing array groups. Unlike the broken power law used in the literature, in this scenario the power law after the peak depends on the macroscopic properties of the phase transition, allowing for a...
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Zafri Ahmed Borboruah (IIT Bombay)15/05/2024, 14:30Gravity & Gravitational Waves
We show that observations of primordial gravitational waves of inflationary origin can shed light into the scale of flavor violation in a flavon model. The mass hierarchy of fermions can be explained by a flavon field. If it exists, the energy density stored in oscillations of the flavon field around the minimum of its potential redshifts as matter and is expected to dominate over radiation in...
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Wenqi Ke (University of Minnesota)15/05/2024, 14:45Gravity & Gravitational Waves
Different inflation models make testable predictions that are often close to each other, and breaking this degeneracy (i.e. distinguishing different models) may then require additional observables. In this talk, we explore the minimal production of gravitational waves during reheating after inflation, arising from the minimal coupling of the inflaton to gravity. The subsequent signal shows a...
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Yunjia Bao (University of Chicago)15/05/2024, 15:00Gravity & Gravitational Waves
Gravitational-wave (GW) signals offer unique probes into the early universe dynamics, particularly those from topological defects. We investigate a scenario involving a two-step phase transition resulting in a network of domain walls bound by cosmic strings. By introducing a period of inflation between the two phase transitions, we show that the stochastic GW signal can be greatly enhanced....
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Ms Lekhika Malhotra (Indian Institute of Technology Bombay)15/05/2024, 15:15Gravity & Gravitational Waves
The dynamical generation of right-handed-neutrino (RHN) masses $M_N$ in the early Universe naturally entails the heavy scalar $\phi$, responsible for B-L symmetry breaking, whose decay in early universe leads to novel Gravitational Waves (GW) spectral shapes arising from the propagation of primordial tensor modes generated during inflation and that re-enter the horizon before or during an...
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Amit Tiwari15/05/2024, 16:00Gravity & Gravitational Waves
We explore a variety of composite topological structures that arise from the spontaneous breaking of SO(10) to SU(3)c × U(1)em via one of its maximal subgroups SU(5) × U(1)χ, SU(4)c × SU(2)L × SU(2)R, and SU(5) × U(1)X (also known as flipped SU(5)). They include i) a network of ℤ strings which develop monopoles and turn into necklaces with the structure of ℤ2 strings, ii) dumbbells connecting...
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Källan Berglund (Penn State IGC)15/05/2024, 16:15Gravity & Gravitational Waves
In my recent publication, Quasiclassical solutions for static quantum black holes, we derive novel nonlocal effects near the horizon of a quantum-corrected black hole. In this talk, I will outline two follow-up papers nearing submission. The first reinterprets this model as a quantum superposition of classical black hole spacetimes with a gaussian distribution of varying mass, broadening the...
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Marcell Howard15/05/2024, 16:30Gravity & Gravitational Waves
Primordial black holes (PBHs) are plausible dark matter candidates that formed from the gravitational collapse of primordial density fluctuations. Current observational constraints allow asteroid-mass PBHs to account for all of the cosmological dark matter. We show that elastic scattering of a cosmological gravitational wave background, these black holes generate spectral distortions on the...
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Manuel Diaz15/05/2024, 16:45Gravity & Gravitational Waves
A new form of quasiclassical space-time dynamics for constrained systems reveals how quantum effects can be derived systematically from canonical quantization of gravitational systems. These quasiclassical methods lead to additional fields, representing quantum fluctuations and higher moments, that are coupled to the classical metric components. The new fields describe nonadiabatic quantum...
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Mudit Rai (Texas AM University)15/05/2024, 17:00Gravity & Gravitational Waves
We investigate the effects of change in temperature of thermal bath via non-adiabatic conditions on the phase transition and it's gravitational wave signature. Our preliminary results show that it is possible to get gravitational waves with shifted frequency due to the thermal kick to the bath in the early universe. This is a novel result and is ubiquitous in scenarios with non-instantaneos...
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Arthur Wu15/05/2024, 17:15Gravity & Gravitational Waves
In this talk we will be exploring a new paradigm where we establish a complementarity of Stochastic gravitational waves with the discovery of Neutral Heavy Lepton in the colliders.
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Yannis GeorisGravity & Gravitational Waves
Hot viscous plasmas unavoidably emit a gravitational wave background, similar to the electromagnetic black body radiation. We study the contribution from hidden particles to the diffuse background emitted by the primordial plasma in the early universe. While this contribution can easily dominate over that from Standard Model particles, we find that both are capped by a generic upper bound that...
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