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Paulus C. Tjiang

Publications and source records attributed to Paulus C. Tjiang.

5 recordsLinked to original sources
arXiv2021

Destroying Kaluza-Klein and Kerr-Newman black holes

We investigate the destroying of charged and rotating black holes in Einstein-Maxwell-(dilaton) theory. We show that a test particle with some appropriate properties in the black hole background can turn the black hole into a naked singularity. In this work, we neglect the self-force, self-energy, and radiative effects as considered by some others in literature. As the result, we are able to show that the Kerr-Newman and Kaluza-Klein black holes can be destroyed by the test particle. Furthermore, for Kaluza-Klein black hole, we consider the overspinning of the black hole by a neutral test scalar field.

gr-qc↗
arXiv2011

The Gaussian formula and spherical aberration of the static and moving curved mirrors from Fermat's principle

The Gaussian formula and spherical aberrations of the static and relativistic curved mirrors are analyzed using the optical path length (OPL) and Fermat's principle. The geometrical figures generated by the rotation of conic sections about their symmetry axes are considered for the shapes of the mirrors. By comparing the results in static and relativistic cases, it is shown that the focal lengths and the spherical aberration relations of the relativistic mirrors obey the Lorentz contraction. Further analysis of the spherical aberrations for both static and relativistic cases have resulted in the information about the limits for the paraxial approximation, as well as for the minimum speed of the systems to reduce the spherical aberrations.

physics.class-ph↗
arXiv2006

Efficiency of Carnot Cycle with Arbitrary Gas Equation of State

The derivation of the efficiency of Carnot cycle is usually done by calculating the heats involved in two isothermal processes and making use of the associated adiabatic relation for a given working substance's equation of state, usually the ideal gas. We present a derivation of Carnot efficiency using the same procedure with Redlich-Kwong gas as working substance to answer the calculation difficulties raised by Agrawal and Menon. We also show that using the same procedure, the Carnot efficiency may be derived regardless of the functional form of the gas equation of state.

physics.class-ph↗
arXiv2004

On the Derivation of Conserved Quantities in Classical Mechanics

Using a theorem of partial differential equations, we present a general way of deriving the conserved quantities associated with a given classical point mechanical system, denoted by its Hamiltonian. Some simple examples are given to demonstrate the validity of the formulation.

physics.class-ph↗