7 papers
Suppressing Extra-Dimensional Axion Isocurvature Dynamically
Gongjun Choi, Tony Gherghetta
Extra-dimensional QCD axion is well motivated by string compactifications and enjoys enhanced protection against quality-violating effects. If present during inflation, however, it…
An Extra-Dimensional Axion in a 5D Warped Orbifold GUT
Gongjun Choi, Tony Gherghetta
We study the QCD axion arising from the 5th component of a bulk gauge field in a five-dimensional warped grand unified theory, and determine the viable range of the axion de…
Non-invertible Chiral Symmetry and Axions under Electromagnetic Duality
Gongjun Choi, Tony Gherghetta, John Terning
We study the implications of non-invertible chiral symmetry in a four-dimensional U(1) gauge theory coupled to massless fermions with electromagnetic duality. Th…
Cheshire terms, Aharonov-Bohm effects, and axions
Shi Chen, Aleksey Cherman, Gongjun Choi +1
We discuss unusual terms that can appear in field theories that allow global vortices. These `Cheshire terms' induce Aharonov-Bohm effects for some particles that move arou…
The Role of the Curvaton Post-Planck
Gongjun Choi, Wenqi Ke, Keith A. Olive
The expected improvements in the precision of inflationary physics observables including the scalar spectral index and the tensor-to-scalar ratio will reveal more than…
Inflaton Production of Scalar Dark Matter through Fluctuations and Scattering
Gongjun Choi, Marcos A. G. Garcia, Wenqi Ke +3
We study the effects on particle production of a Planck-suppressed coupling between the inflaton and a scalar dark matter candidate, . In the absence of this coupling, the domin…
Minimal Production of Prompt Gravitational Waves during Reheating
Gongjun Choi, Wenqi Ke, Keith A. Olive
The inflationary reheating phase begins when accelerated expansion ends. As all Standard Model particles are coupled to gravity, gravitational interactions will lead to particle pr…