Research Fields 2010
Theoretical Cosmology | Dark Energy and Modified Gravities
Faculty: Dr. Burin Gumjudpai
Research Sudents: [Ph.D./S.TP.] Rachan Rangdee
Research Sudents: [M.S./L.TP. ] Chakkrit Kaeonikhom, Phatchaya Maneekhum
- Present acceleration of the universe is not capable for GR to explain. This motivated idea of dark energy in form of scalar field. Dark energy could be scalar field because the field can render negative pressure and repulsive gravity. The scalar field is predicted in symmetrical breaking of fundamental force at beyond 1 TeV. This energy scale is the target that experiments at the LHC is trying to reach. A few types of scalar field is also motivated from string theories such as phantom canonical, Dirac-Born-Infeld, tachyonic and etc. Scalar-tensor theory of gravity is an example of alternative to GR gravity. Chameleon gravity is one derived-type of the scalar-tensor theory. Chameleon scalar field's mass of the scalar field depends on the matter density of its environment. It can be heavy enough in the lab to avoid the tight constraints, and it can still remain relatively light on cosmological scales. The other model that we consider is the Eddington-Born-Infeld model. We can calculate related physical quantities of the models to be checked by results from observations and from experiments. We aim to be able to constraint and rule out some model of alternative gravity. Testing and investigating these models would more or less help constructing the realistic model of quantum gravity.
Quantum Field Theory | Schwinger’s Formalism
Faculty: Dr. Nattapong Yongram
- Quantum Field Theory "QFT", a unification of quantum mechanics and special relativity nowaday becomes an accurate physics espectially for proceses in quantum electrodynamics "QED". At TPTP, Schwinger's formalism for the QED and Electroeweak Theory "EW". We consider behavior of pair particles produced in fundamental process of QED and EW. Our study reveals that probability of measuring spin-polarization correlation of pair particles depends on velocity of the initial particles or initial strings. This result is different from what obtains in ordinary quantum mechanics which considers only kinematic effects and also violates Bell's inequality. We found that the pair particles have also entanglement behavior.
Non-Equilibrium Thermodynamics
Faculty: Dr. Burin Gumjudpai
- As known, absolute temperature "T" has played a role of fundamental abstarct physical quantity which can not be measured directly. The 0th law of thermodynamics laid foundation stone for the existence of T as a basic state function. Then the whole body of equilibrium thermodynamics can be developed from it. As equivalent to the 0th law and T, the 2nd law of thermodynamics gives the light for the existence of entropy "S". From here, the new branch of "dissipative" structure of thermodynamics arises. I am curious about this new structure and wonder how we can apply them to the other subjects like (1) signal systems (2) ecological physics (3) economical physics and (4) traffic flows.