Related papers: What no one has seen before: gravitational wavefor…
The expansion history and content of the Universe between the end of inflation and the onset of Big Bang Nucleosynthesis is mostly unknown. In this paper, we study gravitational waves (GWs) induced by matter isocurvature fluctuations in a…
Gravitational waves are a potential direct probe for the multi-dimensional flow during the first second of core-collapse supernova explosions. Here we outline the structure of the predicted gravitational wave signal from neutrino-driven…
Using adiabatic point-particle black hole perturbation theory, we simulate plausible gravitational wave~(GW) signatures in two exotic scenarios (i) where a small black hole is emitted by a larger one ('black hole emission') and (ii) where a…
Gravitational-wave detectors on earth have detected gravitational waves from merging compact objects in the local Universe. In future we will detect gravitational waves from higher-redshift sources, which trace the high-redshift structure…
Coule's primary objection to the Alcubierre "warpdrive" is that the material producing the warp field needs to be superluminal. This difficulty is solved by placing the drive material inside its own warp field (making the drive system part…
We investigate the gravitational wave background from a first order phase transition in a matter-dominated universe, and show that it has a unique feature from which important information about the properties of the phase transition and…
The direct detection of gravitational waves offers an exciting new window onto our Universe. At the same time, multiple observational evidence and theoretical considerations motivate the presence of physics beyond the Standard Model. In…
Following on after three previous papers discussing the formation of primordial black holes in the early universe during the radiation dominated era, we present here related results considering the theoretical possibility of having a fluid…
The gravitational wave memory effect is characterized by the permanent relative displacement of a pair of initially comoving test particles that is caused by the passage of a burst of gravitational waves. Recent research on this effect has…
Gravitational waves, detected a century after they were first theorized, are spacetime distortions caused by some of the most cataclysmic events in the universe, including black hole mergers and supernovae. The successful detection of these…
We investigate the potential of gravitational-wave background searches to constrain cosmic histories characterised by a stiff equation of state, preceded by a period of matter domination. Such a scenario leads to a characteristic peak in…
The stability of the spin of pulsars and the precision with which these spins can be determined, allows many unique tests of interest to physics and astrophysics. Perhaps the most challenging and revolutionary of these, is the detection of…
The nascent field of gravitational-wave astronomy offers many opportunities for effective and inspirational astronomy outreach. Gravitational waves, the "ripples in space-time" predicted by Einstein's theory of General Relativity, are…
Negative masses have long been explored, but their observational viability remains unclear. In this work, we develop a unified, observationally testable framework to constrain negative masses using both coupling level and dynamical probes.…
Noncommutative gravity is a natural method of quantizing spacetime by promoting the spacetime coordinates themselves to operators which do not commute. This approach is motivated, for example, from a quantum gravity perspective, among…
We propose a novel semiclassical mechanism to unify quantum mechanics and general relativity, where wave function collapse in a superposition state induces a rapid change in the energy-momentum tensor, triggering spacetime dynamics that…
Alcubierre warp drive metric is coupled to quantum mechanical scalar matter field. The requirement of the exotic matter for the warp drive is mapped into a conformal wave equation. This result into a fourth order partial differential…
The general properties of a perfect relativistic fluid resulting from the quantum gravitational anomaly are investigated. It is found that, in the limit of a weak gravitational field, this fluid possesses a polytropic equation of state…
We investigate the cosmological production of gravitational waves in a nonsingular flat cosmology powered by a "running vacuum" energy density described by $\rho_{\Lambda}\equiv\rho_{\Lambda}(H)$, a phenomenological expression potentially…
We numerically investigate the propagation of plane gravitational waves in the form of an initial boundary value problem with de Sitter initial data. The full non-linear Einstein equations with positive cosmological constant $\lambda$ are…