Publications (51)
Inflationary Magnetogenesis with Broken Local U(1) Symmetry
Guillem Domènech, Chunshan Lin, Misao Sasaki
We point out that a successful inflationary magnetogenesis could be realised if we break the local U(1) gauge symmetry during inflation. The effective electric charge is fixed as a…
Non-Gaussianity from false vacuum inflation: Old curvaton scenario
Jinn-Ouk Gong, Chunshan Lin, Yi Wang
We calculate the three-point correlation function of the comoving curvature perturbation generated during an inflationary epoch driven by false vacuum energy. We get a novel false…
Hidden-sector accretion and warped black-string seeds for high-redshift supermassive black holes
Chunshan Lin
The earliest massive black holes are often discussed in terms of heavy baryonic seeds, primordial black holes, or super-Eddington accretion. We develop a different possibility: a c…
Cosmological perturbations of self-accelerating universe in nonlinear massive gravity
A. Emir Gumrukcuoglu, Chunshan Lin, Shinji Mukohyama
We study cosmological perturbations of self-accelerating universe solutions in the recently proposed nonlinear theory of massive gravity, with general matter content. While the bro…
Non-Gaussianity, Isocurvature Perturbation, Gravitational Waves and a No-Go Theorem for Isocurvaton
Miao Li, Chunshan Lin, Tower Wang +1
We investigate the isocurvaton model, in which the isocurvature perturbation plays a role in suppressing the curvature perturbation, and large non-Gaussianity and gravitational wav…
Bypassing the Lyth Bound with Entangled Gravitons: Primordial Signatures and Late-Time Noise
Shingo Akama, Chunshan Lin
We demonstrate that quantum entanglement between primordial gravitons in dynamically decoupled gravitational sectors can parametrically enhance the tensor power spectrum during inf…
Topological Inflation with Large Tensor-to-scalar Ratio
Yu-Chieh Chung, Chunshan Lin
BICEP2's detection on the primordial B-mode of CMB polarization suggests that inflation occurred around GUT scale, with the tensor-to-scalar ratio r~0.2. Inspired by this discosver…
Holographic Gas as Dark Energy
Miao Li, Xiao-Dong Li, Chunshan Lin +1
We investigate the statistical nature of holographic gas, which may represent the quasi-particle excitations of a strongly correlated gravitational system. We find that the hologra…
On the cosmology of massive gravity
Antonio De Felice, A. Emir Gumrukcuoglu, Chunshan Lin +1
We present a review of cosmological solutions in non-linear massive gravity, focusing on the stability of perturbations. Although homogeneous and isotropic solutions have been foun…
Cosmological Perturbations in Extended Massive Gravity
A. Emir Gumrukcuoglu, Kurt Hinterbichler, Chunshan Lin +2
We study cosmological perturbations around self-accelerating solutions to two extensions of nonlinear massive gravity: the quasi-dilaton theory and the mass-varying theory. We exam…
Novel matter coupling in Einstein gravity
Chunshan Lin, Zygmunt Lalak
A general framework of the novel matter coupling in the Einstein gravity is introduced. We firstly prove that a class of theories whose Hamiltonian constraint is given by an arbitr…
The Self-consistent Matter Coupling of a Class of Minimally Modified Gravity Theories
Chunshan Lin
The self-consistent matter coupling is found in a broad class of minimally modified gravity theories which was discovered recently. All constraints in the theories remain first cla…
Quadra-Spectrum and Quint-Spectrum from Inflation and Curvaton Models
Chunshan Lin, Yi Wang
We calculate the quadra-spectrum and quint-spectrum, corresponding to five and six point correlation functions of the curvature perturbation. For single field inflation with standa…
SO(3) massive gravity
Chunshan Lin
In this paper, we propose a massive gravity theory with 5 degrees of freedom. The mass term is constructed by 3 Stuckelberg scalar fields, which respects SO(3) symmetry in the fiel…
Scalar-assisted magnetogenesis during the radiation-dominated epoch
Alexander Ganz, Chunshan Lin, Mian Zhu
We propose a novel mechanism to generate primordial magnetic fields (PMFs) strong enough to explain the observed cosmic magnetic fields. We employ a scalar field charged under U(1)…
Graviton to Photon Conversion via Parametric Resonance
Robert Brandenberger, Paola C. M. Delgado, Alexander Ganz +1
We study the parametric resonance excitation of the electromagnetic field by a gravitational wave. We show that there is narrow band resonance. For an electromagnetic field in the…
Inflationary epoch in the presence of holographic dark energy
Paola C. M. Delgado, Alexander Ganz, Chunshan Lin
We analyze the effects of the holographic dark energy model in a single field slow-roll inflation, taking into account both the holographic and the dark radiation components. In pa…
Novel matter coupling in general relativity via canonical transformation
Katsuki Aoki, Chunshan Lin, Shinji Mukohyama
We study canonical transformations of general relativity (GR) to provide a novel matter coupling to gravity. Although the transformed theory is equivalent to GR in vacuum, the equi…
Constraining the Gravitational Wave Speed in the Early Universe via Gravitational Cherenkov Radiation
Paola C. M. Delgado, Alexander Ganz, Chunshan Lin +1
Scalar particles traveling faster than a subluminal gravitational wave generate gravitons via gravitational Cherenkov radiation. In this paper, we investigate graviton production b…
Massive gravity and the suppression of anisotropies and gravitational waves in a matter-dominated contracting universe
Chunshan Lin, Jerome Quintin, Robert H. Brandenberger
We consider a modified gravity model with a massive graviton, but which nevertheless only propagates two gravitational degrees of freedom and which is free of ghosts. We show that…
An effective field theory of holographic dark energy
Chunshan Lin
A general covariant local field theory of the holographic dark energy model is presented. It turns out the low energy effective theory of the holographic dark energy is the massive…
Hamiltonian structure of scalar-tensor theories beyond Horndeski
Chunshan Lin, Shinji Mukohyama, Ryo Namba +1
We study the nature of constraints and the Hamiltonian structure in a scalar-tensor theory of gravity recently proposed by Gleyzes, Langlois, Piazza and Vernizzi (GLPV). For the si…
Open FRW universes and self-acceleration from nonlinear massive gravity
A. Emir Gumrukcuoglu, Chunshan Lin, Shinji Mukohyama
In the context of a recently proposed nonlinear massive gravity with Lorentz-invariant mass terms, we investigate open Friedmann-Robertson-Walker (FRW) universes driven by arbitrar…
Scalar parity-odd trispectrum from gravitational Chern-Simons interaction vertices
Giorgio Orlando, Shingo Akama, Chunshan Lin
In this paper, we explore parity violation in a scalar trispectrum from a dynamical Chern-Simons gravity theory. So far, a graviton-mediated diagram with two vertexes being of gene…
Structure Formation in the Effective Field Theory of Holographic Dark Energy
Alexander Ganz, Chunshan Lin
We investigate the structure formation in the effective field theory of the holographic dark energy. The equation of motion for the energy contrast of the cold dark matter i…
Gravitational wave constraints on the primordial black hole dominated early universe
Guillem Domènech, Chunshan Lin, Misao Sasaki
We calculate the gravitational waves (GWs) induced by the density fluctuations due to inhomogeneous distribution of primordial black holes (PBHs) in the case where PBHs eventually…
Sound speed resonance of the stochastic gravitational wave background
Yi-Fu Cai, Chunshan Lin, Bo Wang +1
We propose a novel mechanism to test time variation of the propagation speed of gravitational waves (GWs) in light of GWs astronomy. As the stochastic GWs experience the whole hist…
Einstein-Gauss-Bonnet gravity in 4-dimensional space-time
Dražen Glavan, Chunshan Lin
In this Letter we present a general covariant modified theory of gravity in space-time dimensions which propagates only the massless graviton and bypasses the Lovelock's…
Massive Graviton on a Spatial Condensate
Chunshan Lin
In this paper, we consider the spatial gauge symmetries spontaneously break down in GR, and graviton becomes massive on this spatial condensate background. Such model can be consid…
Phenomenology in type-I minimally modified gravity
Katsuki Aoki, Antonio De Felice, Chunshan Lin +2
We study cosmology in a class of minimally modified gravity (MMG) with two local gravitational degrees of freedom. We classify modified gravity theories into type-I and type-II: th…
Resonant Primordial Gravitational Waves Amplification
Chunshan Lin, Misao Sasaki
We propose a mechanism to evade the Lyth bound in models of inflation. We minimally extend the conventional single-field inflation model in general relativity (GR) to a theory with…
Large Hierarchy from Non-minimal Coupling
Chunshan Lin
In this paper, a model is proposed to solve the gauge hierarchy problem. Beyond the standard model, we introduce an extra scalar field that non-minimally couples to gravity. The fu…
Cosmic Superstrings Revisited in Light of NANOGrav 15-Year Data
John Ellis, Marek Lewicki, Chunshan Lin +1
We analyze cosmic superstring models in light of NANOGrav 15-year pulsar timing data. A good fit is found for a string tension and a string intercomm…
A Class of Minimally Modified Gravity Theories
Chunshan Lin, Shinji Mukohyama
We investigate the Hamiltonian structure of a class of gravitational theories whose actions are linear in the lapse function. We derive the necessary and sufficient condition for a…
Primordial Non-Gaussianities from the Trispectra in Multiple Field Inflationary Models
Xian Gao, Miao Li, Chunshan Lin
We investigate the primordial non-Gaussianities from the trispectra in multi-field inflation models, which can be seen as generalization of multi-field -inflation and multi-DBI…
Hamiltonian analysis of metric-affine- theory
Dražen Glavan, Tom Zlosnik, Chunshan Lin
Determining the number of propagating degrees of freedom in metric-affine theories of gravity requires the use of Hamiltonian constraint analysis, except in some subclasses of theo…
Gravitational wave signal from massive gravity
A. Emir Gumrukcuoglu, Sachiko Kuroyanagi, Chunshan Lin +2
We discuss the detectability of gravitational waves with a time dependent mass contribution, by means of the stochastic gravitational wave observations. Such a mass term typically…
Gravitational waves from high-power twisted light
Eduard Atonga, Killian Martineau, Ramy Aboushelbaya +12
Recent advances in high-energy and high-peak-power laser systems have opened up new possibilities for fundamental physics research. In this work, the potential of twisted light for…
Nonlinear stability of cosmological solutions in massive gravity
Antonio De Felice, A. Emir Gumrukcuoglu, Chunshan Lin +1
We investigate nonlinear stability of two classes of cosmological solutions in massive gravity: isotropic Friedmann-Lemaitre-Robertson-Walker (FLRW) solutions and anisotropic FLRW…
On primordial trispectrum from exchanging scalar modes in general multiple field inflationary models
Xian Gao, Chunshan Lin
We make an complementary investigation of the primordial trispectrum from exchanging intermediate scalar modes in multi-field inflation models with generalized kinetic terms. Toget…
Observational signatures of the parametric amplification of gravitational waves during reheating after inflation
Sachiko Kuroyanagi, Chunshan Lin, Misao Sasaki +1
We study the evolution of Gravitational Waves (GWs) during and after inflation as well as the resulting observational consequences in a Lorentz-violating massive gravity theory wit…
Resolving the Ostrogradsky Ghost Problem for a Class of Scalar-tensor Theories
Chunshan Lin
We perform a Hamiltonian analysis and prove that a large class of scalar-tensor theories whose Lagrangian is given by a generic function $F\left(K_{ab},N,R_{ab},h^{ab},\nabla_a,t\r…
Effective Field Theory of Broken Spatial Diffeomorphisms
Chunshan Lin, Lance Z. Labun
We study the low energy effective theory describing gravity with broken spatial diffeomorphism invariance. In the unitary gauge, the Goldstone bosons associated with broken diffeom…
Some Issues Concerning Holographic Dark Energy
Miao Li, Chunshan Lin, Yi Wang
We study perturbation of holographic dark energy and find it be stable. We study the fate of the universe when interacting holographic dark energy is present, and discuss a simple…
A Matter Bounce By Means of Ghost Condensation
Chunshan Lin, Robert H. Brandenberger, Laurence Perreault Levasseur
Assuming the existence of a scalar field which undergoes "ghost condensation" and which has a suitably chosen potential, it is possible to obtain a non-singular bouncing cosmology…
Hamiltonian Analysis of an On-shell U(1) Gauge Field Theory
Chunshan Lin, Misao Sasaki
We perform the Hamiltonian analysis of an on-shell U(1) gauge field theory, in which the action is not invariant under local U(1) transformations but recovers the invariance when t…
CMB Scale Dependent Non-Gaussianity from Massive Gravity during Inflation
Guillem Domènech, Takashi Hiramatsu, Chunshan Lin +3
We consider a cosmological model in which the tensor mode becomes massive during inflation, and study the Cosmic Microwave Background (CMB) temperature and polarization bispectra a…
Scale dependences of local form non-Gaussianity parameters from a DBI isocurvature field
Qing-Guo Huang, Chunshan Lin
We derive the spectral indices and their runnings of local form and from a DBI isocurvature field and we find that the indices are suppressed by the sound speed $…
Anisotropic Friedmann-Robertson-Walker universe from nonlinear massive gravity
A. Emir Gumrukcuoglu, Chunshan Lin, Shinji Mukohyama
In the scope of the nonlinear massive gravity, we study fixed points of evolution equations for a Bianchi type--I universe. We find a new attractor solution with non-vanishing anis…
Parametric resonance of gravitational waves in general scalar-tensor theories
Yi-Fu Cai, Guillem Domènech, Alexander Ganz +3
Gravitational waves offer a potent mean to test the underlying theory of gravity. In general theories of gravity, such as scalar-tensor theories, one expects modifications in the f…
Reconstruction of the isocurvaton scenario
Miao Li, Chunshan Lin
This paper has been withdrawn by the authors due to an unlikely results.