5 papers
Vacuum expectation values in non-trivial background space from three types of UV improved Green's functions
Nahomi Kan, Masashi Kuniyasu, Kiyoshi Shiraishi +1
We evaluate the quantum expectation values in non-simply connected spaces by using UV improved Green's functions proposed by Padmanabhan, Abel, and Siegel. It is found that the res…
Equivalent Hamiltonian approach to quantum cosmology of integrable models
Nahomi Kan, Masashi Kuniyasu, Kiyoshi Shiraishi +1
We propose an approach to quantum cosmology of integrable models. To analyze the models with two dynamical variables, we introduce equivalent Hamiltonians in reduced phase spaces,…
Accelerating cosmologies in an integrable model with noncommutative minisuperspace variables
Nahomi Kan, Masashi Kuniyasu, Kiyoshi Shiraishi +1
We study classical and quantum noncommutative cosmology with a Liouville-type scalar degree of freedom. The noncommutativity is imposed on the minisuperspace variables through a de…
Integrable higher-dimensional cosmology with separable variables in an Einstein-dilaton-antisymmetric field theory
Nahomi Kan, Masashi Kuniyasu, Kiyoshi Shiraishi +1
We consider a -dimensional cosmological model with a dilaton field and two -form field strengths which have nonvanishing fluxes in extra dimensions. Exact solutions for…
Can we identify massless braneworld black holes by observations?
M. Kuniyasu, K. Nanri, N. Sakai +3
For an extension of the previous work on gravitational lensing by massless braneworld black holes, we investigate their microlensing phenomena and shadows and discuss how to distin…