125 citations · 300 across the 20 of their papers we have counts for
20 papers
Islands in Bianchi type-I Universe
Ido Ben-Dayan, Merav Hadad, Ayushi Srivastava
We study the conditions for finding an island in an anisotropic universe - Bianchi Type-I filled with radiation. We verify that the existence of islands does not depend on their sh…
Islands in the Fluid: Islands are Common in Cosmology
Ido Ben-Dayan, Merav Hadad, Elizabeth Wildenhain
We discuss the possibility of entanglement islands in cosmological spacetimes with a general perfect fluid with an equation of state . We find that flat universes with time-symm…
Proposed evolution in Marolf-Maxfield toy model obtained through correspondence to spontaneous collapse theory
Merav Hadad
The Marolf-Maxfield topological toy model for 2D gravity gives the full spectrum of boundary theories, but can not describe any evolution. In order to obtain the expected evolution…
The Grand Canonical Multiverse and the Small Cosmological Constant
Ido Ben-Dayan, Merav Hadad, Amir Michaelis
We consider the Multiverse as an ensemble of universes. Using standard statistical physics analysis we get that the Cosmological Constant (CC) is exponentially small. The small and…
Thermodynamical Interpretation of the Second Law for Cosmology
Ido Ben-Dayan, Merav Hadad
The area of a future holographic screen increases monotonically. Associating this area with entropy results in a generalized second law for Cosmology (GSLC). Unlike black hole hori…
Truncation of Einstein equations through Gravitational Foliation
Merav Hadad
In previous works, we suggested considering a (3+1)D quantum gravitational field as an evolution of a (2+1)D renormalized quantum gravitational field along the direction of the gra…
Derivation of Hamilton-like equations on a non-Cauchy hypersurface and their expected connection to quantum gravity theories
Merav Hadad, Levy Rosenblum
Recently it was found that quantum gravity theories may involve constructing a quantum theory on non-Cauchy hypersurfaces. However this is problematic since the ordinary Poisson br…
Non-Cauchy surface foliations and their expected connection to quantum gravity theories
Merav Hadad
We argue that quantum gravity theories should involve constructing a quantum theory on non-Cauchy hypersurfaces and suggest that the hypersurface direction should be the same as th…
The space time DoF surface density as a phase-space of accelerating reference frames
Merav Hadad
Padmanabhan found a definition for the surface density of space time degrees of freedom. We prove that this density can be constructed from a phase space which is derived with resp…
The two canonical conjugate pairs at the horizon of a D1D5 black hole
Merav Hadad, Levy Rosenblum
The Euclidian opening angle at the surface, at the horizon of a black hole is canonically conjugate to the black hole entropy. We prove that for a black…
Wave function of the quantum black hole
Ram Brustein, Merav Hadad
We show that the Wald Noether charge entropy is canonically conjugate to the opening angle at the horizon. Using this canonical relation we extend the Wheeler-DeWitt equation to a…
Evaluating the Wald Entropy from two-derivative terms in quadratic actions
Ram Brustein, Dan Gorbonos, Merav Hadad +1
We evaluate the Wald Noether charge entropy for a black hole in generalized theories of gravity. Expanding the Lagrangian to second order in gravitational perturbations, we show th…
Comparison of Variations of Statistical and Wald's Entropies
Merav Hadad, Judy Kupferman
We write the variation of the statistical entropy of matter fields outside a black hole along a Killing vector. This is done for generalized theories of gravity, using a Lie deriva…
The Einstein equations for generalized theories of gravity and the thermodynamic relation are equivalent
Ram Brustein, Merav Hadad
We show that the equations of motion of generalized theories of gravity are equivalent to the thermodynamic relation . Our proof relies on extending previous arguments b…
Wald's entropy is equal to a quarter of the horizon area in units of the effective gravitational coupling
Ram Brustein, Dan Gorbonos, Merav Hadad
The Bekenstein-Hawking entropy of black holes in Einstein's theory of gravity is equal to a quarter of the horizon area in units of Newton's constant. Wald has proposed that in gen…
Production of fermions in models of string cosmology
Ram Brustein, Merav Hadad
Production of spin 1/2 fermions and gravitinos by the standard mechanism of amplification of quantum fluctuations during the dilaton-driven inflation phase in models of string cosm…
Dark Matter in Models of String Cosmology
Ram Brustein, Merav Hadad
The origin of dark matter in the universe may be weakly interacting scalar particles produced by amplification of quantum fluctuations during a period of dilaton-driven inflation.…
Cold and Hot Dark Matter from a Single Nonthermal Relic
Ram Brustein, Merav Hadad
The origin of dark matter in the universe may be scalar particles produced by amplification of quantum fluctuations during a period of dilaton-driven inflation. We show, for the fi…
Dark Matter Axions in Models of String Cosmology
Ram Brustein, Merav Hadad
Axions are produced during a period of dilaton-driven inflation by amplification of quantum fluctuations. We show that for some range of string cosmology parameters and some range…
Particle production in string cosmology models
Ram Brustein, Merav Hadad
We compute spectra of particles produced during a dilaton-driven kinetic inflation phase within string cosmology models. The resulting spectra depend on the parameters of the model…