Publications (80)
Black hole solutions in mimetic Born-Infeld gravity
Che-Yu Chen, Mariam Bouhmadi-López, Pisin Chen
The vacuum, static, and spherically symmetric solutions in the mimetic Born-Infeld gravity are studied. The mimetic Born-Infeld gravity is a reformulation of the Eddington-inspired…
Eddington-inspired-Born-Infeld tensorial instabilities neutralized in a quantum approach
Imanol Albarran, Mariam Bouhmadi-López, Che-Yu Chen +1
The recent direct detection of gravitational waves has highlighted the huge importance of the tensorial modes in any extended gravitational theory. One of the most appealing approa…
Doomsdays in a modified theory of gravity: A classical and a quantum approach
Imanol Albarran, Mariam Bouhmadi-López, Che-Yu Chen +1
By far cosmology is one of the most exciting subject to study, even more so with the current bulk of observations we have at hand. These observations might indicate different kinds…
Probing Palatini-type gravity theories through gravitational wave detections via quasinormal modes
Che-Yu Chen, Mariam Bouhmadi-López, Pisin Chen
The possibility of testing gravity theories with the help of gravitational wave detections has become an interesting arena of recent research. In this paper, we follow this directi…
Annihilation-to-nothing: a quantum gravitational boundary condition for the Schwarzschild black hole
Mariam Bouhmadi-López, Suddhasattwa Brahma, Che-Yu Chen +2
The interior of a static Schwarzschild metric can be written in terms of two functions, similar to some models of anisotropic cosmology. With a suitable choice of canonical variabl…
Quantum cosmology of Eddington-Born-Infeld gravity fed by a scalar field: the big rip case
Imanol Albarran, Mariam Bouhmadi-López, Che-Yu Chen +1
We study the quantum avoidance of the big rip singularity in the Eddington-inspired-Born-Infeld (EiBI) phantom model. Instead of considering a simple phantom dark energy component,…
Testing loop quantum gravity from observational consequences of non-singular rotating black holes
Suddhasattwa Brahma, Che-Yu Chen, Dong-han Yeom
The lack of rotating black hole models, which are typically found in nature, in loop quantum gravity (LQG) substantially hinders the progress of testing LQG from observations. Star…
On the Consistency of the Wheeler-DeWitt Equation in the Quantized Eddington-inspired Born-Infeld Gravity
Mariam Bouhmadi-López, Che-Yu Chen, Pisin Chen
We re-examine the quantum geometrodynamical approach within the Eddington-inspired-Born-Infeld theory of gravity, which was first proposed in our previous work [1]. A thorough anal…
Modified Eddington-inspired-Born-Infeld Gravity with a Trace Term
Che-Yu Chen, Mariam Bouhmadi-Lopez, Pisin Chen
In this paper, a modified Eddington-inspired-Born-Infeld (EiBI) theory with a pure trace term being added to the determinantal action is analysed from a cosmological po…
On the Possible Spacetime Structures of Rotating Loop Quantum Black Holes
Che-Yu Chen
To date, a mathematically consistent construction of effective rotating black hole models in the context of Loop Quantum Gravity (LQG) is still lacking. In this work, we start with…
Regular Instantons in the Eddington-inspired-Born-Infeld Gravity: Lorentzian Wormholes from Bubble Nucleations
Mariam Bouhmadi-López, Che-Yu Chen, Pisin Chen +1
The O(4)-symmetric regular instanton solutions are studied within the framework of the Eddington-inspired-Born-Infeld gravity (EiBI). We find that the behavior of the solution woul…
Characterising the Magnetic Fields of Nearby Molecular Clouds using Submillimeter Polarization Observations
Colin H. Sullivan, Laura Fissel, Patrick King +3
Of all the factors that influence star formation, magnetic fields are perhaps the least well understood. The goal of this paper is to characterize the 3D magnetic field properties…
Change of Magnetic FieldGas Alignment at Gravity-Driven Alfvénic Transition in Molecular Clouds: Implications for Dust Polarization Observations
Che-Yu Chen, Patrick K. King, Zhi-Yun Li
Diffuse striations in molecular clouds are preferentially aligned with local magnetic fields whereas dense filaments tend to be perpendicular to them. When and why this transition…
Quasinormal modes of black holes encircled by a gravitating thin disk
Che-Yu Chen, Petr KotlaÅÃk
The ringdown phase of gravitational waves emitted by a perturbed black hole is described by a superposition of exponentially decaying sinusoidal modes, called quasinormal modes (QN…
Curved accretion disks around rotating black holes without reflection symmetry
Che-Yu Chen, Hsiang-Yi Karen Yang
Rotating black holes without equatorial reflection symmetry can naturally arise in effective low-energy theories of fundamental quantum gravity, in particular, when parity-violatin…
Generating Rotating Spacetime in Ricci-Based Gravity: Naked Singularity as a Black Hole Mimicker
Wei-Hsiang Shao, Che-Yu Chen, Pisin Chen
Motivated by the lack of rotating solutions sourced by matter in General Relativity as well as in modified gravity theories, we extend a recently discovered exact rotating solution…
Imaging a semi-classical horizonless compact object with strong redshift
Che-Yu Chen, Yuki Yokokura
The recent advancements in black hole imaging have opened a new era of probing horizon-scale physics with electromagnetic radiation. However, a feature of the observed images, a br…
Geometry, Kinematics, and Magnetization of Simulated Prestellar Cores
Che-Yu Chen, Eve C. Ostriker
We utilize the more than 100 gravitationally-bound dense cores formed in our three-dimensional, turbulent MHD simulations reported in Chen & Ostriker (2015) to analyze structural,…
A novel test of gravity via black hole eikonal correspondence
Che-Yu Chen, Yu-Jui Chen, Meng-Yuan Ho +1
When adopted in black hole spacetimes, geometric-optics approximations imply a mapping between the quasinormal mode (QNM) spectrum of black holes in the eikonal limit and black hol…
Vector Horndeski black holes in nonlinear electrodynamics
Che-Yu Chen, Antonio De Felice, Shinji Tsujikawa +1
On a spherically symmetric and static background, we study the existence of linearly stable black hole (BH) solutions in nonlinear electrodynamics (NED) with a Horndeski vector-ten…
Modified Teleparallel Gravity induced by quantum fluctuations
Che-Yu Chen, Yu-Hsien Kung
In the semi-classical regime, quantum fluctuations embedded in a Riemannian spacetime can be effectively recast as classical back reactions and manifest themselves in the form of n…
The Davis-Chandrasekhar-Fermi Method Revisited
Che-Yu Chen, Zhi-Yun Li, Renato R. Mazzei +5
Despite the rich observational results on interstellar magnetic fields in star-forming regions, it is still unclear how dynamically significant the magnetic fields are at varying p…
Effects of Grain Alignment Efficiency on Synthetic Dust Polarization Observations of Molecular Clouds
Patrick K. King, Che-Yu Chen, Laura M. Fissel +1
It is well known that the polarized continuum emission from magnetically aligned dust grains is determined to a large extent by local magnetic field structure. However, the observe…
Black hole quasinormal modes and isospectrality in Deser-Woodard nonlocal gravity
Che-Yu Chen, Sohyun Park
We investigate the gravitational perturbations of the Schwarzschild black hole in the nonlocal gravity model recently proposed by Deser and Woodard (DW-II). The analysis is perform…
From Bubbles and Filaments to Cores and Disks: Gas Gathering and Growth of Structure Leading to the Formation of Stellar Systems
Jaime E. Pineda, Doris Arzoumanian, Philippe André +8
The study of the development of structures on multiple scales in the cold interstellar medium has experienced rapid expansion in the past decade, on both the observational and the…
Disk Formation in Magnetized Dense Cores with Turbulence and Ambipolar Diffusion
Ka Ho Lam, Zhi-Yun Li, Che-Yu Chen +2
Disks are essential to the formation of both stars and planets, but how they form in magnetized molecular cloud cores remains debated. This work focuses on how the disk formation i…
Modified gravity models for inflation: In conformity with observations
Xinyi Zhang, Che-Yu Chen, Yakefu Reyimuaji
We consider a modified gravity framework for inflation by adding to the Einstein-Hilbert action a direct term, where is identified as the inflaton and is the trac…
Modeling Dust Polarization Observations of Molecular Clouds through MHD Simulations
Patrick K. King, Laura M. Fissel, Che-Yu Chen +1
The BLASTPol observations of Vela C have provided the most detailed characterization of the polarization fraction and dispersion in polarization angles for a molecular clou…
Observational features of reflection asymmetric black holes
Che-Yu Chen, Hung-Yi Pu
The Kerr spacetime is symmetric with respect to a well-defined equatorial plane. When testing the equatorial reflection symmetry of an isolated black hole, one is at the same time…
Twisted doughnuts: Thick disk torus around equatorial asymmetric black hole
Che-Yu Chen, Eva Hackmann, Audrey Trova
The Kerr black hole spacetime is symmetric with respect to a well-defined equatorial plane. When such a symmetry is broken, for instance, by some putative effects beyond general re…
Singular Instantons in Eddington-inspired-Born-Infeld Gravity
Frederico Arroja, Che-Yu Chen, Pisin Chen +1
In this work, we investigate -symmetric instantons within the Eddington-inspired-Born-Infeld gravity theory (EiBI). We discuss the regular Hawking-Moss instanton and find tha…
Testing black hole equatorial reflection symmetry using Sgr A* shadow images
Che-Yu Chen
The recently released images of the supermassive black holes in the M87 galaxy and the galaxy of our own make probing black hole spacetimes and testing general relativity (GR) poss…
Separability of the Klein-Gordon equation for rotating spacetimes obtained from Newman-Janis algorithm
Che-Yu Chen, Pisin Chen
In the literature, the Newman-Janis algorithm (NJA) has been widely used to construct stationary and axisymmetric spacetimes to describe rotating black holes. In addition, it has b…
Quasi-normal modes of massless scalar fields for charged black holes in the Palatini-type gravity
Che-Yu Chen, Pisin Chen
The scrutiny of black hole perturbations and its application to testing gravity theories have been a very crucial frontier in modern physics. In this paper we study the quasi-norma…
Dressed black holes in the new tensor-vector-scalar theory
Reginald Christian Bernardo, Che-Yu Chen
As incarnations of gravity in its prime, black holes are arguably the best target for us to demystify gravity. Keeping in mind the prominent role black holes play in gravitational…
Gravitational perturbations of non-singular black holes in conformal gravity
Che-Yu Chen, Pisin Chen
It is believed that in the near future, gravitational wave detections will become a promising tool not only to test gravity theories, but also to probe extremely curved spacetime r…
Relative Alignment Between the Magnetic Field and Molecular Gas Structure in the Vela C Giant Molecular Cloud using Low and High Density Tracers
Laura M. Fissel, Peter A. R. Ade, Francesco E. Angilè +37
We compare the magnetic field orientation for the young giant molecular cloud Vela C inferred from 500-m polarization maps made with the BLASTPol balloon-borne polarimeter to t…
Traversable Wormhole in Einstein 3-Form Theory With Self-Interacting Potential
Mariam Bouhmadi-López, Che-Yu Chen, Xiao Yan Chew +2
We numerically construct a symmetric wormhole solution in pure Einstein gravity supported by a massive -form field with a potential that contains a quartic self-interaction term…
Regular Black Hole Interior Spacetime Supported by Three-Form Field
Mariam Bouhmadi-López, Che-Yu Chen, Xiao Yan Chew +2
In this paper, we show that a minimally coupled 3-form endowed with a proper potential can support a regular black hole interior. By choosing an appropriate form for the metric fun…
Slow-roll inflation in gravity with a mixing term
Che-Yu Chen, Yakefu Reyimuaji, Xinyi Zhang
We consider slow-roll inflationary models in a class of modified theories of gravity which contains non-minimal curvature-inflaton couplings, i.e., the gravity, where …
The Drag Instability in a 1D Isothermal C-Shock
Pin-Gao Gu, Che-Yu Chen
We investigate whether the drag instability, proposed by Gu et al., occurs in a one-dimensional (1D) C-shock. The 1D background model proposed by Chen and Ostriker for a steady iso…
Primordial bouncing cosmology in the Deser-Woodard nonlocal gravity
Che-Yu Chen, Pisin Chen, Sohyun Park
The Deser-Woodard (DW) nonlocal gravity model has been proposed in order to describe the late-time acceleration of the universe without introducing dark energy. In this paper we fo…
Relative Alignment between Dense Molecular Cores and Ambient Magnetic Field: The Synergy of Numerical Models and Observations
Che-Yu Chen, Erica A. Behrens, Jasmin E. Washington +26
The role played by magnetic field during star formation is an important topic in astrophysics. We investigate the correlation between the orientation of star-forming cores (as defi…
Confronting quantum-corrected teleparallel cosmology with observations
Reginald Christian Bernardo, Che-Yu Chen, Jackson Levi Said +1
It has been shown that at the semi-classical order, gravitational theories with quantum fluctuations can be effectively recast as modified theories of gravity with non-minimal grav…
Relative Alignment Between Magnetic Fields and Molecular Gas Structure in Molecular Clouds
Renato Mazzei, Zhi-Yun Li, Che-Yu Chen +3
We compare the structure of synthetic dust polarization with synthetic molecular line emission from radiative transfer calculations using a 3-dimensional, turbulent collapsing-clou…
Eddington-Born-Infeld cosmology: a cosmographic approach, a tale of doomsdays and the fate of bound structures
Mariam Bouhmadi-Lopez, Che-Yu Chen, Pisin Chen
The Eddington-inspired-Born-Infeld scenario (EiBI) can prevent the Big Bang singularity for a matter content whose equation of state is constant and positive. In a recent paper we…
Modeling CN Zeeman Effect Observations of the Envelopes of a Low-Mass Protostellar Disk and a Massive Protostar
Renato Mazzei, Zhi-Yun Li, Che-Yu Chen +3
We use the POLARIS radiative transfer code to produce simulated circular polarization Zeeman emission maps of the CN molecular line transition for two types of protoste…
Ambipolar Diffusion in Action: Transient C shock Structure and Prestellar Core Formation
Che-Yu Chen, Eve C. Ostriker
We analyze the properties of steady and time-dependent C shocks under conditions prevailing in giant molecular clouds. For steady C shocks, we show that ionization equilibrium hold…
Dynamics in Star-forming Cores (DiSCo): Project Overview and the First Look toward the B1 and NGC 1333 Regions in Perseus
Che-Yu Chen, Rachel Friesen, Jialu Li +13
The internal velocity structure within dense gaseous cores plays a crucial role in providing the initial conditions for star formation in molecular clouds. However, the kinematic p…
The Transition of Polarized Dust Thermal Emission from the Protostellar Envelope to the Disk Scale
Ka Ho Lam, Che-Yu Chen, Zhi-Yun Li +4
Polarized dust continuum emission has been observed with ALMA in an increasing number of deeply embedded protostellar systems. It generally shows a sharp transition going from the…
Resonant orbits of rotating black holes beyond circularity: Discontinuity along parameter shift
Che-Yu Chen, Hsu-Wen Chiang, Avani Patel
According to general relativity, an isolated black hole in vacuum shall be described by the Kerr metric, whose geodesic equations are integrable. The violation of integrability lea…
Annihilation-to-nothing: DeWitt boundary condition inside a black hole
Suddhasattwa Brahma, Che-Yu Chen, Dong-han Yeom
In canonical quantum gravity, the wave function for a hypersurface inside a Schwarzschild black hole can be obtained by solving the Wheeler-DeWitt equation. What is of prime import…
Asymptotic non-flatness of an effective black hole model based on loop quantum gravity
Mariam Bouhmadi-López, Suddhasattwa Brahma, Che-Yu Chen +2
For any non-rotating effective quantum (uncharged) black hole model to be viable, its asymptotic structure of spacetime should reduce to that of a Schwarzschild black hole. After e…
Eikonal black hole ringings in generalized energy-momentum squared gravity
Che-Yu Chen, Pisin Chen
In the scope of black hole spectroscopy, several attempts have been made in the past decades in order to test black holes or gravitational theories via black hole quasinormal modes…
Rotating black holes without symmetry and their shadow images
Che-Yu Chen
The recent detection of gravitational waves from black hole coalescences and the first image of the black hole shadow enhance the possibilities of testing gravitational theories in…
Black Hole Perturbations and Quasinormal Modes in Hybrid Metric-Palatini Gravity
Che-Yu Chen, Yu-Hsien Kung, Pisin Chen
The rapid advancement of gravitational wave astronomy in recent years has paved the way for the burgeoning development of black hole spectroscopy, which enhances the possibility of…
Shadow signatures and energy accumulation in Lorentzian-Euclidean black holes
Emmanuele Battista, Salvatore Capozziello, Che-Yu Chen
The Lorentzian-Euclidean black hole has been recently introduced as a geodesically complete spacetime featuring a signature shift at the event horizon where causal geodesics are pr…
Modeling the Far-Infrared Polarization Spectrum of a High-Mass Star Forming Cloud
Dennis Lee, Che-Yu Chen, Giles Novak +7
The polarization spectrum, or wavelength dependence of the polarization fraction, of interstellar dust emission provides important insights into the grain alignment mechanism of in…
A New Method to Trace Three-dimensional Magnetic Field Structure within Molecular Clouds Using Dust Polarization
Che-Yu Chen, Patrick K. King, Zhi-Yun Li +2
The complete three-dimensional structure of the magnetic field within molecular clouds has eluded determination despite its high value in determining controlling factors in the sta…
Anisotropic Formation of Magnetized Cores in Turbulent Clouds
Che-Yu Chen, Eve C. Ostriker
In giant molecular clouds (GMCs), shocks driven by converging turbulent flows create high-density, strongly-magnetized regions that are locally sheetlike. In previous work, we show…
Shadow of rotating black holes with consistent thermodynamics
Che-Yu Chen, Chiang-Mei Chen, Nobuyoshi Ohta
Quantum effects in general induce scale dependence in the coupling constants. We explore this possibility in gravity, with a scale-dependent Newton coupling. When applied to Kerr b…
Cosmological singularities in Eddington-inspired-Born-Infeld theory and its possible extension
Che-Yu Chen, Mariam Bouhmadi-López, Pisin Chen
The Eddington-inspired-Born-Infeld (EiBI) gravity, which is formulated within the Palatini formalism, is characterized by its ability to cure the big bang singularity in the very b…
Cosmological singularities in Born-Infeld determinantal gravity
Mariam Bouhmadi-Lopez, Che-Yu Chen, Pisin Chen
The Born-Infeld determinantal gravity has been recently proposed as a way to smooth the Big Bang singularity. This theory is formulated on the Weitzenbock space-time and the telepa…
Fantastic Striations and Where to Find Them: Origin of Magnetically Aligned Striations in Interstellar Clouds
Che-Yu Chen, Zhi-Yun Li, Patrick K. King +1
Thin, magnetically aligned striations of relatively moderate contrast with the background are commonly observed in both atomic and molecular clouds. They are also prominent in MHD…
Threshold of primordial black hole formation in Eddington-inspired-Born-Infeld gravity
Che-Yu Chen
It is believed that primordial black holes (PBHs), if they exist, can serve as a powerful tool to probe the early stage of the cosmic history. Essentially, in the radiation dominat…
Is Eddington-Born-Infeld theory really free of cosmological singularities?
Mariam Bouhmadi-Lopez, Che-Yu Chen, Pisin Chen
The Eddington-inspired-Born-Infeld (EiBI) theory has been recently resurrected. Such a theory is characterized by being equivalent to Einstein theory in vacuum but differing from i…
Investigating the Complex Velocity Structures within Dense Molecular Cloud Cores with GBT-Argus
Che-Yu Chen, Shaye Storm, Zhi-Yun Li +12
We present the first results of high-spectral resolution (0.023 km/s) NH observations of dense gas dynamics at core scales (~0.01 pc) using the recently commissioned Argus…
Primordial Cosmology in Mimetic Born-Infeld Gravity
Mariam Bouhmadi-López, Che-Yu Chen, Pisin Chen
The Eddington-inspired-Born-Infeld (EiBI) model is reformulated within the mimetic approach. In the presence of a mimetic field, the model contains non-trivial vacuum solutions whi…
Revealing the drag instability in one-fluid nonideal MHD simulations of a 1D isothermal C-shock
Pin-Gao Gu, Che-Yu Chen, Emma Shen +2
C-type shocks are believed to be ubiquitous in turbulent molecular clouds thanks to ambipolar diffusion. We investigate whether the drag instability in 1D isothermal C-shocks, infe…
Formation of Magnetized Prestellar Cores with Ambipolar Diffusion and Turbulence
Che-Yu Chen, Eve C. Ostriker
We investigate the roles of magnetic fields and ambipolar diffusion during prestellar core formation in turbulent giant molecular clouds (GMCs), using three-dimensional numerical s…
Towards the Quantization of Eddington-inspired-Born-Infeld Theory
Mariam Bouhmadi-López, Che-Yu Chen
The quantum effects close to the classical big rip singularity within the Eddington-inspired-Born-Infeld theory (EiBI) are investigated through quantum geometrodynamics. It is the…
Self-gravitating Filament Formation from Shocked Flows: Velocity Gradients across Filaments
Che-Yu Chen, Lee G. Mundy, Eve C. Ostriker +2
In typical environments of star-forming clouds, converging supersonic turbulence generates shock-compressed regions, and can create strongly-magnetized sheet-like layers. Numerical…
CARMA Large Area Star Formation Survey: Structure and Kinematics of Dense Gas in Serpens Main
Katherine I. Lee, Manuel Fernandez-Lopez, Shaye Storm +21
We present observations of N2H+(1-0), HCO+(1-0), and HCN(1-0) toward the Serpens Main molecular cloud from the CARMA Large Area Star Formation Survey (CLASSy). We mapped 150 square…
Lessons from black hole quasinormal modes in modified gravity
Che-Yu Chen, Mariam Bouhmadi-López, Pisin Chen
Quasinormal modes of perturbed black holes have recently gained much interest because of their tight relations with the gravitational wave signals emitted during the post-merger ph…
Linear stability of vector Horndeski black holes
Che-Yu Chen, Antonio De Felice, Shinji Tsujikawa
Horndeski's vector-tensor (HVT) gravity is described by a Lagrangian in which the field strength of a vector field interacts wit…
Resonant Islands of Effective-One-Body Dynamics
Che-Yu Chen, Feng-Li Lin, Avani Patel
We study the chaotic signatures of the geodesic dynamics of a non-spinning test particle in the effective-one-body (EOB) formalism for the inspiral process of spinning binary black…
Insights in cosmology: the relevance of the connection
Ismael Ayuso, Mariam Bouhmadi-López, Che-Yu Chen +3
We explore the role of the affine connection in gravity, a modified theory where gravity is governed by non-metricity within the symmetric teleparallel framework. Although t…
Eikonal quasinormal modes and photon orbits of deformed Schwarzschild black holes
Che-Yu Chen, Hsu-Wen Chiang, Jie-Shiun Tsao
The geometric optics approximation provides an interpretation for eikonal correspondence that, in black-hole-containing spacetimes, connects high-frequency black hole quasinormal m…
HAWC+/SOFIA Polarimetry in L1688: Relative Orientation of Magnetic Field and Elongated Cloud Structure
Dennis Lee, Marc Berthoud, Che-Yu Chen +14
We present a study of the relative orientation between the magnetic field and elongated cloud structures for the Oph A and Oph E regions in L1688 in the Ophiuchus molecul…
A consistent model of non-singular Schwarzschild black hole in loop quantum gravity and its quasinormal modes
Mariam Bouhmadi-López, Suddhasattwa Brahma, Che-Yu Chen +2
We investigate the interior structure, perturbations, and the associated quasinormal modes of a quantum black hole model recently proposed by Bodendorfer, Mele, and Münch (BMM). W…