124 citations · 250 across the 25 of their papers we have counts for
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Can the Universe Change Signature When Gravity is Dynamical?
Yaghoub Heydarzade
Can a universe undergo a regular Euclidean-Lorentzian signature transition when the gravitational coupling itself is dynamical? We address this question in scalar-tensor gravity wi…
Dynamical and Observational Analysis of Generalized Nash's Theory of Gravity
Amin Rezaei Akbarieh, Mohammad Amin Bolouri, Yaghoub Heydarzade
We investigate cosmic evolution in generalized Nash's theory of gravity involving the quadratic Ricci invariant . The analysis is divided into two complementary bra…
FLRW-Cosmology in Scalar-Vector-Tensor Theories of Gravity
Metin Gürses, Yaghoub Heydarzade
We generalize our previous theorem for FLRW spacetimes within the framework of generic metric gravity theories. In earlier work, we proved that, in the absence of matter fields, th…
Signature Change in Theory
Serkan Doruk Hazinedar, Yaghoub Heydarzade
We investigate a simple gravity model coupled to a scalar field and demonstrate that the theory admits classical degenerate metric solutions, analogous to those known i…
Quantum Cosmology in Theory with Schutz's Perfect Fluid
Serkan Doruk Hazinedar, Yaghoub Heydarzade, Shahram Jalalzadeh
The theory of gravity extends general relativity (GR) by allowing the gravitational Lagrangian to depend on both the Ricci scalar and the trace of the energy-momentum…