804 citations · 3.3k across the 158 of their papers we have counts for
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Method for Solving the Bloch Equation from the Connection with Time-Dependent Oscillator
Sang Pyo Kim
We introduce a novel method to find exact density operators for a spin-1/2 particle in time-dependent magnetic fields by using the one-mode bosonic representation of and th…
Coherent-Squeezed State Representation of Travelling General Gaussian Wave Packets
Sang Pyo Kim
Using the time-dependent annihilation and creation operators, the invariant operators, for a free mass and an oscillator, we find the coherent-squeezed state representation of a tr…
Inflationary Solutions in Nonminimally Coupled Scalar Field Theory
Seoktae Koh, Sang Pyo Kim, Doo Jong Song
We study analytically and numerically the inflationary solutions for various type scalar potentials in the nonminimally coupled scalar field theory. The Hamilton-Jacobi equation is…
Nonlinear Evolutions and Non-Gaussianity in Generalized Gravity
Seoktae Koh, Sang Pyo Kim, Doo Jong Song
We use the Hamilton-Jacobi theory to study the nonlinear evolutions of inhomogeneous spacetimes during inflation in generalized gravity. We find the exact solutions to the lowest o…
First Law of Thermodynamics and Friedmann Equations of Friedmann-Robertson-Walker Universe
Rong-Gen Cai, Sang Pyo Kim
Applying the first law of thermodynamics to the apparent horizon of a Friedmann-Robertson-Walker universe and assuming the geometric entropy given by a quarter of the apparent hori…