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F. P. Zen

Publications and source records attributed to F. P. Zen.

At least 19 recordsLinked to original sources
arXiv2025

Analytical Study for Primordial Non-Gaussianity in the gravity 4D Einstein-scalar-Gauss-Bonnet Inflation

An inflationary model can be constrained by non-gaussian statistics as a parameter in the LSS (Large Scale Structure) distribution, and in the radiation of CMB (Cosmic Microwave Background) fluctuating temperature. Data on the CMB from Planck Collaboration provide up-to-date constraints on the parameters controlling the degree of non-Gaussianity in certain inflationary models, thus supporting or not supporting the model. Setting the non-Gaussianity parameter investigated in this study can be a reference whether or not it is a good parameter in constraining cosmological inflation models. This study attempts to examine the non-Gaussianity of the 3+1-dimensional 4DEGB gravitational cosmological inflation model starting from random field statistics. The non-Gaussian signature generated by the model is quantified, and the parameters controlling the degree of non-Gaussianity are constrained using data observation of Planck Collaboration. The method used in investigating non-Gaussianity is the in-in formalism, applied after obtaining the 3-point of $\zeta$ (curvature perturbation) terms of the perturbation expansion to the third order. The 3-point correlation function helps to create a bispectrum used to investigate the non-gaussinity of the inflation model. The results of this study show that the model tested is the slow roll pressed in the squeezed limit, because it witnesses a dominant local shape function. It has such as the non-gaussianity possessed by the single scalar field inflation as confirmation that Gauss-Bonnet term within Einstein-Hilbert action is topologically invariant in $D<5$ spacetimes.

gr-qc↗
arXiv2021

(3+1)-Formulation for Gravity with Torsion and Non-Metricity II: The Hypermomentum Equation

In this article, we consider a special case of Metric-Affine f(R)-gravity for f(R) = R, i.e. the Metric-Affine General Relativity (MAGR). As a companion to the first article in the series, we perform the (3+1) decomposition to the hypermomentum equation, obtained from the minimization of the MAGR action S [g, ω] with respect to the connection ω. Moreover, we show that the hypermomentum tensor H could be constructed completely from 10 hypersurfaces variables that arise from its dilation, shear, and rotational (spin) parts. The (3+1) hypermomentum equations consists of 1 scalar, 3 vector, 3 matrix, and 1 tensor equation of order-(2,1). Together with the (3+1) decomposition of the traceless torsion constraint, consisting of 1 scalar and 1 vector equation, we obtain 10 hypersurface equations, which are the main result in this article. Finally, we consider some special cases of MAGR, namely, the zero hypermomentum, metric, and torsionless cases. For vanishing hypermomentum, we could retrieve the metric compatibility and torsionless condition in the (3+1) framework, hence forcing the affine connection to be Levi-Civita as in the standard General Relativity.

gr-qc↗
arXiv2021

(3+1)-Formulation for Gravity with Torsion and Non-Metricity: The Stress-Energy-Momentum Equation

We derive the generalized Gauss-Codazzi-Mainardi (GCM) equation for a general affine connection with torsion and non-metricity. Moreover, we show that the metric compatibility and torsionless condition of a connection on a manifold are inherited to the connection of its hypersurface. As a physical application to these results, we derive the (3+1)-Einstein Field Equation (EFE) for a special case of Metric-Affine f(R)-gravity when f(R)=R, the Metric-Affine General Relativity (MAGR). Motivated by the concept of geometrodynamics, we introduce additional variables on the hypersurface as a consequence of non-vanishing torsion and non-metricity. With these additional variables, we show that for MAGR, the energy, momentum, and the stress-energy part of the EFE are dynamical, i.e., all of them contain the derivative of a quantity with respect to the time coordinate. For the Levi-Civita connection, one could recover the Hamiltonian and the momentum (diffeomorphism) constraint, and obtain the standard dynamics of GR.

gr-qc↗
arXiv2020

Hidden conformal symmetry for Kerr-Newman-NUT-AdS black holes

We show the generic non-extremal Kerr-Newman-NUT-AdS black holes are holographically dual to the hidden conformal field theories in two different pictures. The two pictures can be merged together to the dual CFTs in general picture, that are generated by the $SL(2,\mathbb{Z})$ modular group. We also extend the calculation to the extremal limit and find the corresponding quantities. Using the extended central charges from the Kerr/CFT correspondence, we also find agreement between the macroscopic and microscopic entropies. We also find the absorption cross-section of the scalar probes for the generic and extremal Kerr-Newman-NUT-AdS black holes, to further support the different dual CFTs to the black holes.

gr-qc↗
arXiv2020

Driving-assisted open quantum transport in qubit networks

We determine the characteristic of dissipative quantum transport in a coupled qubit network in the presence of on-site and off-diagonal external driving. The work is motivated by the dephasing-assisted quantum transport where noise is beneficial to the transport efficiency. Using Floquet-Magnus expansion extended to Markovian open systems, we analytically derive transport efficiency and compare it to exact numerical results. We find that driving may increase the efficiency at frequencies near the coupling rate. On the contrary, at some other frequencies the transport may be suppressed. We then propose the enhancement mechanism as the ramification of interplay between driving frequency, dissipative, and trapping rates.

quant-ph↗
arXiv2019

Kerr-Newman-NUT-Kiselev black holes in Rastall theory of gravity and Kerr/CFT Correspondence

We present a new twisted rotating black hole solution by performing Demia{ń}ski-Newman-Janis algorithm to the electrically and dyonically charged black hole with quintessence in Rastall theory of gravity. Using our black hole solution, we argue that Rastall gravity is not equivalent with Einstein gravity. For further explanation, the black hole properties such as the horizon and ergosphere are studied for which there are some different properties for those theories. Some thermodynamic properties of the black hole solution are also discussed. At the end, considering the Kerr/CFT correspondence is valid for our black hole solution, the central charge from the CFT of this extremal solution is derived.

gr-qc↗
arXiv2019

Deformed conformal symmetry of Kerr-Newman-NUT-AdS black holes

We find generators of the conformal symmetry for the class of Kerr-Newman-NUT-AdS black holes from the deformed scalar probe equation. We find two classes of solutions for the generators (also known as conformal J and Q pictures). The two classes of deformed generators are the extension of similar generators for the regular conformal symmetry. Moreover, we find that the two pictures can be generalized and extended into a general picture. In each picture, the generators produce an extended local family of SL(2,R)_L \times SL(2,R)_R hidden conformal symmetries for the Kerr-Newman-NUT-AdS black holes which are parameterized by one deformation parameter. We find the absorption cross-section of the scalar probes for the Kerr-Newman-NUT-AdS black holes, which in turn, supports the existence of Kerr/CFT correspondence. Moreover, our deformed conformal generators for the Kerr-Newman-NUT-AdS black holes provide the deformed conformal generators for the non-rotating Reissner-Nordstrom-NUT-AdS black holes.

gr-qc↗
arXiv2018

Hermiticity of the Volume Operators in Loop Quantum Gravity

The aim of this article is to provide a rigorous-but-simple steps to prove the hermiticity of the volume operator of Rovelli-Smolin and Ashtekar-Lewandowski using the angular momentum approach, as well as pointing out some subleties which have not been given a lot of attention previously. Besides of being hermitian, we also prove that both volume operators are real, symmetric, and positive semi-definite, with respect to the inner product defined on the Hilbert space over SU(2). Other special properties follows from this fact, such as the possibility to obtain real orthonormal eigenvectors. Moreover, the matrix representation of the volume operators are degenerate, such that the real positive eigenvalues always come in pairs for even dimension, with an additional zero if the dimension is odd. As a consequence, one has a freedom in choosing the orthonormal eigenvectors for each 2-dimensional eigensubspaces. Furthermore, we provide a formal procedure to obtain the spectrum and matrix representation of the volume operators. In order to compare our procedure with the earlier ones existing in the literature, we give explicit computational examples for the case of monochromatic quantum tetrahedron, where the eigenvalues agrees with the standard earlier procedure.

gr-qc↗
arXiv2012

Dynamics of DNA Bubble in Viscous Medium

The damping effect to the DNA bubble is investigated within the Peyrard-Bishop model. In the continuum limit, the dynamics of the bubble of DNA is described by the damped nonlinear Schrodinger equation and studied by means of variational method. It is shown that the propagation of solitary wave pattern is not vanishing in a non-viscous system. Inversely, the solitary wave vanishes soon as the viscous force is introduced.

q-bio.BM↗
arXiv2012

The thermal denaturation of Peyrard-Bishop model with an external potential

The impact of various types of external potentials to the Peyrard-Bishop DNA denaturation is investigated through statistical mechanics approach. The partition function is obtained using transfer integral method, and further the stretching of hydrogen bond is calculated using time independent perturbation method. It is shown that all types of external potentials accelerate the denaturation processes at lower temperature. In particular, it is argued that the Gaussian potential with infinitesimal width reproduces a constant force at one end of DNA sequence as already done in some previous works.

physics.bio-ph↗
arXiv2012

Near-brane SU(6) origin Higgs in Scherk-Schwarz breaking of five-dimensional SU(6) GUT

The symmetry breaking of five-dimensional SU(6) GUT is realized by Scherk-Schwarz mechanisms through trivial and pseudo nontrivial orbifold S1/Z2 breakings to produce dimensional deconstruction 5D SU(6) \rightarrow4D SU(6). The latter also induces near-brane weakly-coupled SU(6) Baby Higgs to further break the symmetry into SU(3)C \otimes SU(3)H \otimes U(1)C. The model successfully provides a scenario of the origin of (Little) Higgs from GUT scale, produces the (intermediate and light) Higgs boson with the most preferred range and establishes coupling unification and compactification scale correctly.

hep-ph↗
arXiv2011

Dynamics of DNA breathing in the Peyrard-Bishop model with damping and external force

The impact of damping effect and external forces to the DNA breathing is investigated within the Peyrard-Bishop model. In in the continuum limit, the dynamics of the breathing of DNA is described by the forced-damped nonlinear Schrodinger equation and studied by means of variational method. The analytical solutions are obtained for special cases. It is shown that the breather propagation is decelerated in the presence of damping factor without the external force, while the envelope velocity and the amplitude increase significantly with the presence of external force. It is particularly found that the higher harmonic terms are enhanced when the periodic force is applied. It is finally argued that the external force accelerates the DNA breathing.

physics.bio-ph↗
arXiv2011

Proton decay in 5D SU(6) GUT with orbifold S^1/Z_2 breaking in Scherk-Schwarz mechanism

Proton decay within 5-dimensional SU(6) GUT with orbifold S^1/Z_2 breaking is investigated using Scherk-Schwarz mechanism. It is shown that in the model neither leptoquark like heavy gauge bosons nor violation of baryon number conservation are allowed due to the orbifold breaking parity splitting. These results prevent too short proton lifetime within the model.

hep-ph↗
arXiv2011

Kaluza-Klein brane cosmology with a bulk scalar field

The brane-world cosmological model in higher-dimensional spacetime with a bulk scalar field is investigated. We derive the $(4+n)$-dimensional gravitational field equations for the scalar field on the $(3+n)$-brane in a $(5+n)$-dimensional bulk with Einstein gravity plus a self-interacting scalar field. The $(4+n)$-dimensional gravitational field equations can be formulated to standard form with the extra component. Using this formalism we study the Kaluza-Klein brane cosmology. We derive the Friedmann equation and a possible energy leak out of the brane into the bulk. We present some exact solutions corresponding to vacuum brane and matter on the brane.

gr-qc↗
arXiv2010

Anharmonic oscillation effect on the Davydov-Scott monomer in thermal bath

The dynamics of Davydov-Scott monomer in a thermal bath with higher order amide-site's displacement leads to anharmonic oscillation effect is investigated using full-quantum approach and the Lindblad formulation of master equation. The specific heat is calculated based on the thermodynamic partition function using the path integral method. The temperature dependence of the specific heat is studied. In the model the specific heat anomaly as pointed out in recent works by Ingold et.al is also observed. However it is found that the anomaly occurs at high temperature region, and the anharmonic oscillation restores the positivity of specific heat.

cond-mat.stat-mech↗
arXiv2005

The Low Energy Effective Equations of Motion for Multibrane World Gravity

The three 3-brane system with both positive or negative tension is studied in a low energy regime by using gradient expansion method. The effective equations of motion on the brane is derived and in particular we examine, in the first order, the radion effective lagrangian for this system. In this case, we show the solution of the modified Friedmann equation with dark radiation on the middle brane and the other 3-branes by direct elimination of the radion fields and Weyl scaling of the metric on the branes. We also derived the scalar-tensor gravity on the branes.

hep-th↗
arXiv2005

On Orbifold Compactification of N=2 Supergravity in Five Dimensions

We study compactification of five dimensional ungauged N=2 supergravity coupled to vector- and hypermultiplets on orbifold $S^1/Z_2$. In the model the vector multiplets scalar manifold is arbitrary while the hypermultiplet scalars span a generalized self dual Einstein manifold constructed by Calderbank and Pedersen. The bosonic and the fermionic sector of the low energy effective N=1 supergravity in four dimensions are derived.

hep-th↗