Article
Astronomy & Astrophysics
John F. Donoghue, Gabriel Menezes
Summary: In theories with higher time derivatives, the Hamiltonian analysis predicts an instability, but this instability can be avoided in some cases. The Hamiltonian treatment does not correspond to the way these theories are treated in quantum field theory.
Article
Physics, Particles & Fields
Nicolo Burzilla, Breno L. Giacchini, Tiberio de Paula Netto, Leonardo Modesto
Summary: The paper investigates the Newtonian limit of higher-derivative gravity theories, including the effects of one-loop quantum corrections. It shows that curvature-derivative invariants may diverge in local theories, but can be regularized in nonlocal theories. Additionally, it demonstrates that quantum corrections do not affect the regularity of the Newtonian limit, and confirms the universality of the leading quantum correction in all theories studied.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Astronomy & Astrophysics
Leslaw Rachwal, Leonardo Modesto, Aleksandr Pinzul, Ilya L. Shapiro
Summary: The study derives the one-loop beta functions for the four-derivative terms in a minimal six-derivative quantum gravity theory in four spacetime dimensions. It shows that the theory is asymptotically free under certain conditions, describing free gravitons but may encounter ghostlike states at different energy scales. The possibility of extending the theory with operators cubic in Riemann tensor to address this issue is proposed.
Article
Astronomy & Astrophysics
Nicolo Burzilla, Breno L. Giacchini, Tiberio de Paula Netto, Leonardo Modesto
Summary: The Newtonian metric potentials for fourth-derivative gravity with one-loop logarithm quantum corrections were derived. The modified Newtonian potential near the origin was shown to be improved compared to the classical one, but the curvature singularity at r = 0 remains. The results are based on a rigorous proof involving numerical and analytic computations.
Article
Physics, Multidisciplinary
Xian Gao
Summary: The authors made a comprehensive classification of scalar monomials and covariant derivatives up to the third order, emphasizing their importance in effective field theory and exploring their complementarity; through systematic classification and derivation, a complete basis of monomials was derived with the potential for novel ghostfree Lagrangians; in addition, diagrammatic representations were developed to simplify the analysis process.
SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY
(2021)
Article
Astronomy & Astrophysics
Andreas G. A. Pithis, Johannes Thuerigen
Summary: The study reveals that tensor field theories exhibit different characteristics from scalar field theories at different length scales under certain conditions, with the phenomenon of symmetry restoration.
Article
Astronomy & Astrophysics
Mahdi Godazgar, George Long
Summary: In this article, the study of asymptotic gravitational charges is discussed, with a focus on higher derivative charges. The authors find a connection between higher derivative Bondi-Metzner-Sachs (BMS) charges and two-derivative BMS charges. It is noted that internal Lorentz transformations are relevant in the higher derivative case unlike the two-derivative case. The article provides a prescription for the precise definition of these charges and derives the associated charges, once again establishing a relationship with two-derivative BMS charges.
Article
Physics, Particles & Fields
Dalia Saha, Mohosin Alam, Ranajit Mandal, Abhik Kumar Sanyal
Summary: A viable quantum theory prohibits the inclusion of curvature invariant terms of different higher orders in the gravitational action. The study demonstrates a conflict between curvature squared and Gauss-Bonnet squared terms in terms of hermiticity, suggesting that one should choose either of them, but not both, in addition to the Einstein-Hilbert term. The early cosmic evolution is explored with the Gauss-Bonnet squared term included.
Article
Physics, Particles & Fields
M. Asorey, F. Falceto, L. Rachwal
Summary: Completing gauge theories with higher derivative terms in the ultraviolet can greatly alter their behavior at high energies. The presence of a large number of derivatives leads to strong interactions, while a low number maintains asymptotic freedom. Consistency issues associated with extra ghosts in higher derivative theories may not affect asymptotically free theories.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Astronomy & Astrophysics
Yuri Makeenko
Summary: This article investigates the two-dimensional four-derivative conformal theory derived from the Nambu-Goto string by path-integration. By using the method of singular products, the author demonstrates that the one-loop approximation provides an exact solution. The solution can be conveniently described using minimal models, where the central charge c in the Kac spectrum depends on the parameters of the four-derivative action. This relation is nonlinear, allowing the mapping of the domain of physical parameters to c < 1, bypassing the KPZ barrier of the Liouville action.
Article
Astronomy & Astrophysics
Ahmad Ghodsi, Malihe Siahvoshan
Summary: The study examines the holographic renormalization group flow with higher-order curvature corrections, identifying critical points near local extrema of the potential and the existence of bounce solutions. Unlike EH gravity, the superpotential in the bulk theory may have upper and lower bounds for couplings, with the behavior of the RG flow being controlled by singular curves. This research sheds light on the existence of a c-function in the presence of such corrections.
Article
Astronomy & Astrophysics
Pawan Joshi, Sukanta Panda
Summary: This paper discusses the Ostrogradsky instability issue in nondegenerate higher-order derivative theories, which can be resolved by removing degeneracy in such theories. By decomposing and checking the degeneracy hidden in the Lagrangian, conditions under which the Ostrogradsky instability does not appear can be found.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Physics, Particles & Fields
Wagno Cesar e Silva, Ilya L. Shapiro
Summary: This article explores the decoupling issue of the massive ghost mode in the 4D theory of the conformal factor of the metric. It analyzes the asymptotic behavior of the derived one-loop nonlocal form factors in the UV and IR limits. The results reproduce the Minimal Subtraction scheme-based beta functions in the UV domain and show that the structures contributing to the running of parameters in the IR are correlated with the divergent part from the effective low-energy theory of the conformal factor.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Physics, Particles & Fields
Nephtali Eliceo Martinez-Perez, Cupatitzio Ramirez
Summary: We study the quantum cosmology of supersymmetric, homogeneous and isotropic, higher derivative models. We recall the superfield actions and derive classically equivalent actions leading to second order equations for bosons and first order equations for fermions. Upon quantization, the algebra of fermions leads to a multi-component state that is annihilated by the Hamiltonian and supersymmetric constraint operators. We obtain asymptotic wave functions of the oscillatory type and exact exponential wave functions, which provide probability distributions of the initial curvature compatible with those obtained using the non-supersymmetric model.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Astronomy & Astrophysics
Cao H Nam
Summary: The study presents a novel holographic model and incorporates higher derivative corrections to investigate the color superconductivity (CSC) phase, demonstrating the unique properties of CSC in the context of EGB gravity.
Article
Astronomy & Astrophysics
Nelson R. F. Braga, Octavio C. Junqueira
Summary: This study investigates the influence of rotation on the transition temperature of strongly interacting matter produced in non-central heavy ion collisions. By using a holographic description of an AdS black hole, the authors extend the analysis to the more realistic case where the matter spreads over a region around the rotational axis. The results show the coexistence of confined and deconfined phases and are consistent with the concept of local temperature in rotating frames developed by Tolman and Ehrenfest.
Article
Astronomy & Astrophysics
Bing Sun, Jiachen An, Zhoujian Cao
Summary: This paper investigates the effect of gravitational constant variation on the propagation of gravitational waves. By employing two analytical methods, the study finds that variations in the gravitational constant result in amplitude and phase corrections for gravitational waves, and the time variation of the gravitational constant can be constrained through the propagation of gravitational waves.
Article
Astronomy & Astrophysics
Abdellah Touati, Zaim Slimane
Summary: This letter presents the first study of Hawking radiation as a tunneling process within the framework of non-commutative gauge theory of gravity. The non-commutative Schwarzschild black hole is reconstructed using the Seiberg-Witten map and the star product. The emission spectrum of outgoing massless particles is computed using the quantum tunneling mechanism. The results reveal pure thermal radiation in the low-frequency scenario, but a deviation from pure thermal radiation in the high-frequency scenario due to energy conservation. It is also found that noncommutativity enhances the correlations between successively emitted particles.
Article
Astronomy & Astrophysics
Shahar Hod
Summary: The travel times of light signals between two antipodal points on a compact star's surface are calculated for two different trajectories. It is shown that, for highly dense stars, the longer trajectory along the surface may have a shorter travel time as measured by asymptotic observers. A critical value of the dimensionless density-area parameter is determined for constant density stars to distinguish cases where crossing through the star's center or following a semi-circular trajectory on the surface has a shorter travel time as measured by asymptotic observers.