Jusak Sali Kosasih

How many quanta are there in a quantum spacetime

Following earlier insights by Livine and Terno, we develop a technique for describing quantum states of the gravitational field in terms of coarse grained spin networks. We show that the number of nodes and links and the values of the spin depend on the observables chosen for the description of the state. Hence the question in the title of this paper is ill posed, unless further information about what is been measured is given.

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.

Gravitoelectromagnetism in teleparallel equivalent of general relativity: A new alternative

Spaniol and Andrade introduced grvitoelectromagnetism in TEGR by considering superpotentials, times the determinant of tetrads, as the gravitoelectromagnetic fields. However, since this defined gravitoelectromagnetic field strength does not give rise to a complete set of Maxwell-like equations, we propose an alternative definition of the gravitoelectromagnetic field strength: instead of superpotentials, torsions are taken as the gravitoelectromagnetic field strengths. Based on this new proposal we are able to derive a complete set of Maxwell-like equations. We then apply them to obtain explicit expressions of the gravitoelectromagnetic fields both in Schwarzchilds spacetime and for gravitational waves.

Curvatures and discrete Gauss–Codazzi equation in (2 + 1)-dimensional loop quantum gravity

We derive the Gauss-Codazzi equation in the holonomy and plane-angle representations and we use the result to write a Gauss-Codazzi equation for a discrete (2+1)-dimensional manifold, triangulated by isosceles tetrahedra. This allows us to write operators acting on spin network states in (2+1)-dimensional loop quantum gravity, representing the 3-dimensional intrinsic, 2-dimensional intrinsic, and 2-dimensional extrinsic curvatures.

Localization of interacting fields in five-dimensional braneworld models

We study localization properties of fundamental fields which are coupled to one another through the gauge mechanism both in the original Randall-Sundrum (RS) and in the modified Randall-Sundrum (MRS) braneworld models: scalar-vector, vector-vector, and spinor-vector configuration systems. For this purpose we derive conditions of localization, namely the finiteness of integrals over the extra coordinate in the action of the system considered. We also derive field equations for each of the systems and then obtain their solutions corresponding to the extra dimension by a separation of variable method for every field involved in each system. We then insert the obtained solutions into the conditions of localization to seek whether or not the solutions are in accordance with the conditions of localization. We obtain that not all of the configuration systems considered are localizable on the brane of the original RS model while, on the contrary, they are localizable on the MRS braneworld model with some restrictions. In terms of field localizability on the brane, this result shows that the MRS model is much better than the original RS model.

Possibility of gravitational quantization under the teleparallel theory of gravitation

Teleparallel gravity (TG) or tele-equivalent general relativity (TEGR) is an alternative gauge theory for gravity. In TG tetrad fields are defined to express gravitational fields and act like gauge potentials in standard gauge theory. The lagrangians for the gravitational field in TG and for the Yang-Mills field in standard gauge theory differ due to different indices that stick on the components of the corresponding fields: two external indices for tetrad field and internal and external indices for the Yang-Mills field. Different types of indices lead to different possible contractions and thus lead to different expression of the lagrangian for the Yang Mills field and for the tetrad field. As TG is a gauge theory it is then natural to quantize gravity in TG by applying the same procedure of quantization as in the standard gauge theory. Here we will discuss on the possibility to quantize gravity, canonically and functionally, under the framework of TG theory.

Localization of a system of vector and scalar fields in a modified Randall-Sundrum model

We study the localization properties of fields in a system of vector and scalar fields in a modified Randall-Sundrum model introduced in ref [1]. The fields are mutually coupled through the gauge mechanism. The metric of the model is conformally flat, has an exponential warp factor, and is physically distinct to the original Randall-Sundrum metric model. We derive general conditions for field localization for this system of matter fields and solve the solution for field equation corresponding to extra dimension. We obtain that the warp factor should decrease with the warp factor parameter k=1. Each type of fields solely is able to localize but all fields cannot.We analyze from the equation motions of scalar fields and vector fields to find the solution of extra dimension. We obtain that this solution for scalar and vector fields differ in general. We derive the localization properties for the both cases, massless and massive scalar fields. We then compare the properties with that as shown in ref [1] for v...

Review on (little-like) baby Higgs in the breaking of 5-dimensional SU(6) GUT through Scherk-Schwarz mechanism in near-brane area

The symmetry breaking of 5-dimensional SU(6) GUT to the electroweak scale is presented. The breaking is realized through Scherk-Schwarz mechanism and orbifold, S1/Z2 for the breaking of 5-dimensional SU(6) to 4-dimensional SU(6) followed by SU(3)C×SU(3)H×U(1)C via SU(6) Baby Higgs or the will-be SimplestLittleHiggs scalar and subsequently SU(3)H to SU(2)L×U(1)B through little-like Higgs mechanism. The little-like Higgs is dynamically generated from the SU(6) breaking. The model provides a scenario of the origin for SU(6) baby Higgs and SU(3) little-like Higgs from the GUT scale.

Dynamical symmetry breaking of SU(6) GUT in 5—dimensional spacetime with orbifold S1/Z2

The symmetry breaking of 5—dimensional SU(6) GUT into 4—dimensional SU(3)⊗SU(3)⊗U(1) with orbifold S1/Z2 through Scherk‐Schwarz mechanism is investigated. It is shown that the origin of Little Higgs can be generated to further break SU(3)⊗SU(3)U(1) down to the electroweak scale through Higgs mechanism. This provides a new example of the source of Little Higgs from the physics at GUT scale.

PROTON DECAY IN 5D–SU(6) GUT WITH ORBIFOLD S1/Z2 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.