Gauss Bonnet Interaction Research Articles

Second order higher-derivative corrections in Double Field Theory

HSZ Double Field Theory is a higher-derivative theory of gravity with exact and manifest T-duality symmetry. The first order corrections in the massless sector were shown to be governed solely by Chern-Simons deformations of the three-form field strength. We compute the full action with up to six derivatives mathcal{O}left({alpha}^{prime 2}right) for the universal sector containing the metric, two-form and dilaton fields. The Green-Schwarz transformation of the two-form field remains uncorrected to second order. In addition to the expected Chern-Simons-squared and Riemann-cubed terms the theory contains a cubic Gauss-Bonnet interaction, plus other six-derivative unambiguous terms involving the three-form field strength whose presence indicates that the theory must contain further higher-derivative corrections.

Late Time Acceleration with Gauss Bonnet Interaction

We present some solutions of late time transition to accelerating universe showing quintessence, phantom or a de-Sitter era of expansion at late time in a FLRW spacetime using Gauss-Bonnet-scalar interaction in the Einstein Hilbert action. In one solution a phantom era of late time acceleration evolves to a Big Rip singularity. The Chameleon mechanism shows that correction to the Newton law could be small.

Late Time Acceleration in Scalar-Tensor Theory with GB Interaction

We present some solutions of late time transition to an accelerating universe showing a quintessence or a de-Sitter era of expansion at late time using Gauss-Bonnet interaction in a Jordan Brans-Dicke theory in FLRW spacetime. The Gauss-Bonnet term yields an effective cosmological constant characterized by a de-Sitter era of late time expansion when the Gauss-Bonnet interaction is equivalent with an ideal fluid. The quintessence era of late time expansion have been obtained assuming the evolution of scalar field is a single valued function. The Chameleon mechanism shows that the correction to the Newton law could be small.

Transient crossing of phantom divide line w Λ = − 1 under Gauss–Bonnet interaction

Smooth double crossing of the phantom barrier w Λ = − 1 has been found possible in cosmological model with Gauss–Bonnet-scalar interaction, in the presence of background cold dark matter. Such crossing has been observed to be a sufficiently late time phenomena and independent of the sign of Gauss–Bonnet-scalar interaction. The luminosity distance versus redshift curve shows a perfect fit with the Λ CDM model up to z = 3.5.

If Gauss–Bonnet interaction plays the role of dark energy

Abstract A cosmological model has been constructed with Gauss–Bonnet-scalar interaction, where the Universe starts with exponential expansion but encounters infinite deceleration, q → ∞ and infinite equation of state parameter, w → ∞ . During evolution it subsequently passes through the stiff fluid era, q = 2 , w = 1 , the radiation dominated era, q = 1 , w = 1 / 3 and the matter dominated era, q = 1 / 2 , w = 0 . Finally, deceleration halts, q = 0 , w = − 1 / 3 , and it then encounters a transition to the accelerating phase. Asymptotically the Universe reaches yet another inflationary phase q → − 1 , w → − 1 . Such evolution is independent of the form of the potential and the sign of the kinetic energy term, i.e., even a non-canonical kinetic energy is unable to phantomize ( w − 1 ) the model.

Brane world cosmology with Gauss-Bonnet interaction

We study a Randall-Sundrum model modified by a Gauss-Bonnet interaction term. We consider, in particular, a Friedmann-Robertson-Walker metric on the brane and analyse the resulting cosmological scenario. It is shown that the usual Friedmann equations are recovered on the brane. The equation of state relating the enery density and the pressure is uniquely determined by the matching conditions. A cosmological solution with negative pressure is found.

No ghost state of Gauss–Bonnet interaction in warped backgrounds

A general solution to the Einstein field equations with the Gauss–Bonnet (GB) term in an AdS 5 bulk background implies that the GB coupling α can take either sign (+ or −), though a positive α will be more meaningful. By considering linearized gravity with the GB term in the Randall–Sundrum (RS) a singular 3-brane model, we study the gravitational interactions between matter sources localized on the brane. With correctly defined boundary conditions on the brane, we find a smooth behavior of graviton propagators and hence the zero-mode solution as a 4d massless graviton localized on the brane with correct momentum and tensor structures. The coupling α modifies the graviton propagators both on the brane and in the bulk. The issue on ghost state of the GB term is resolved, and we find that there is no real ghost (negative norm) state of the GB term in the RS single brane picture. The latter condition leads to a consistency in the coupling between the brane matter and the bulk gravity. We also elucidate about the possibilities for behavior of a test particle on the brane and in the bulk.

Gravitational potential correction with Gauss–Bonnet interaction

A treatment of linearized gravity with the Einstein-Gauss-Bonnet interaction terms in $D\geq$ 5 is given in the Randall-Sundrum brane background. This Letter has outlined some interesting features of the brane world gravity and Newtonian potential correction with the GB interaction term. We find that the GB coupling $\alpha$ renormalizes the effective four-dimensional Newton constant on the brane, and also additionally contributes to the correction term of the Newtonian potential. Indeed, the GB term does not affect the massless graviton mode and the Einstein gravity on the brane, and quite interestingly, such term in $D\geq 5$ appears to give more information about the necessary boundary condition(s) to be satisfied by the zero mode wavefunction on the brane(s). small (and preferably positive) GB coupling $\alpha$.

Gravity in the Einstein–Gauss–Bonnet theory with the Randall–Sundrum background

Abstract We obtain the full 5D graviton propagator in the Randall–Sundrum model with the Gauss–Bonnet interaction. From the decomposition of the graviton propagator on the brane, we show that localization of gravity arises in the presence of the Gauss–Bonnet term. We also obtain the metric perturbation for observers on the brane with considering the brane bending and compute the amplitude of one massless graviton exchange. For the positive definite amplitude or no ghost states, the sign of the Gauss–Bonnet term should be negative in our convention, which is compatible with string amplitude computations. In that case, the ghost-free condition is sufficient for obtaining the Newtonian gravity. For a vanishing Gauss–Bonnet coefficient, the brane bending allows us to reproduce the correct graviton polarizations for the effective 4D Einstein gravity.

Erratum to “Various modified solutions of the Randall–Sundrum model with the Gauss–Bonnet interaction” [Nucl. Phys. B 582 (2000) 296

Erratum to “Various modified solutions of the Randall–Sundrum model with the Gauss–Bonnet interaction” [Nucl. Phys. B 582 (2000) 296

Various modified solutions of the Randall–Sundrum model with the Gauss–Bonnet interaction

The Gauss-Bonnet interaction is the only consistent quadratic interaction below the Planck scale in the Randall-Sundrum compactification. We study various static and inflationary solutions including this Gauss-Bonnet interaction.

Effective Gauss-Bonnet interaction in Randall-Sundrum compactification

The effective gravitational interaction below the Planck scale in the Randall-Sundrum world is shown to be the Gauss-Bonnet term. In this theory we find that there exists another static solution with a positive bulk cosmological constant. Also, there exist solutions for positive visible sector cosmological constant, which are needed for a later Friedman-Robertson-Walker universe.