Publications (64)
Extracting Energy from a Black Hole through Its Disk
Li-Xin Li
When some magnetic field lines connect a Kerr black hole with a disk rotating around it, energy and angular momentum are transferred between them. If the black hole rotates faster…
Inferring the Inclination of a Black Hole Accretion Disk from Observations of its Polarized Continuum Radiation
Li-Xin Li, Ramesh Narayan, Jeffrey E. McClintock
Spin parameters of stellar-mass black holes in X-ray binaries are currently being estimated by fitting the X-ray continuum spectra of their accretion disk emission. For this method…
Inflation in Kaluza-Klein Theory: Relation between the Fine-Structure Constant and the Cosmological Constant
Li-Xin Li, J. Richard Gott, III
In this paper we investigate a model of an inflationary universe in Kaluza-Klein theory, which is a four-dimensional de Sitter space plus a one-dimensional compactified internal sp…
Electromagnetic Energy for a Charged Kerr Black Hole in a Uniform Magnetic Field
Li-Xin Li
With the Komar mass formula we calculate the electromagnetic energy for a charged Kerr black hole in a uniform magnetic field. We find that the total electromagnetic energy takes t…
Gamma-Ray Burst Precursors as the Remnant of the Thermal Radiation Initially Trapped in the Fireball
Li-Xin Li
In the standard fireball model of gamma-ray bursts (GRBs), the fireball starts with an optically thick phase. As it expands, the fireball becomes optically thin at some stage. The…
Semi-Analytical Models for Lensing by Dark Halos: I. Splitting Angles
Li-Xin Li, Jeremiah P. Ostriker
We use the semi-analytical approach to analyze gravitational lensing of quasars by dark halos in various cold dark matter (CDM) cosmologies, in order to determine the sensitivity o…
A Note on the Kaluza-Klein Theory
Li-Xin Li
We show that the Kaluza-Klein theory contains a fundamental problem: The four-dimensional metric tensor and the electromagnetic potential vector assumed in the Kaluza-Klein theory…
Potential super-hard Osmium di-nitride with fluorite structure: First-principles calculations
Chang-Zeng Fan, Song-Yan Zeng, Li-Xin Li +4
We have performed systematic first-principles calculations on di-carbide, -nitride, -oxide and -boride of platinum and osmium with the fluorite structure. It is found that only PtN…
Multiway Junction Conditions: Booklets and Webs
Jia-Yin Shen, Cheng Peng, Li-Xin Li
Junction conditions play a crucial role in constructing new gravity solutions. In this paper, we derive the junction condition for gluing together an arbitrary number of spacetimes…
Gamma-Ray Emission Produced by -process Elements from Neutron Star Mergers
Meng-Hua Chen, Li-Xin Li, Da-Bin Lin +1
The observation of a radioactively powered kilonova AT~2017gfo associated with the gravitational wave-event GW170817 from binary neutron star merger proves that these events are id…
Quasi-Periodic Oscillations from Rayleigh-Taylor and Kelvin-Helmholtz Instability at a Disk-Magnetosphere Interface
Li-Xin Li, Ramesh Narayan
We consider the interface between an accretion disk and a magnetosphere surrounding the accreting mass. We argue that such an interface can occur not only with a magnetized neutron…
Multi-Temperature Blackbody Spectrum of a Thin Accretion Disk around a Kerr Black Hole: Model Computations and Comparison with Observations
Li-Xin Li, Erik R. Zimmerman, Ramesh Narayan +1
We use a ray-tracing technique to compute the observed spectrum of a thin accretion disk around a Kerr black hole. We include all relativistic effects such as frame-dragging, Doppl…
Observational Signatures of the Magnetic Connection between a Black Hole and a Disk
Li-Xin Li
In this Letter we use a simple model to demonstrate the observational signatures of the magnetic connection between a black hole and a disk: (1) With the magnetic connection more e…
Making Clean Energy with a Kerr Black Hole: a Tokamak Model for Gamma-Ray Bursts
Li-Xin Li
In this paper we present a model for making clean energy with a Kerr black hole. Consider a Kerr black hole with a dense plasma torus spinning around it. A toroidal electric curren…
A Self-Consistent Vacuum for Misner Space and the Chronology Protection Conjecture
Li-Xin Li, J. Richard Gott, III
In this paper we find a self-consistent vacuum for Misner space. For this "adapted" Rindler vacuum the renormalized stress-energy tensor is zero throughout the Misner space. A poin…
Radioactive -Ray Emissions from Neutron Star Mergers
Li-Xin Li
Gravitational waves and electromagnetic radiations from a neutron star merger were discovered on 17 August 2017. Multiband observations of the optical transient have identified bri…
A Toy Model for Blandford-Znajek Mechanism
Li-Xin Li
A toy model for the Blandford-Znajek mechanism is investigated: a Kerr black hole with a toroidal electric current residing in a thin disk around the black hole. The toroidal elect…
Evolution of Magnetic Fields around a Kerr Black Hole
Li-Xin Li
The evolution of magnetic fields frozen to a perfectly conducting plasma fluid around a Kerr black hole is investigated. We focus on the plunging region between the black hole hori…
The X-Ray Transient 080109 in NGC 2770: an X-Ray Flash Associated with a Normal Core-Collapse Supernova
Li-Xin Li
Although it is generally thought that long-duration gamma-ray bursts (LGRBs) are associated with core-collapse supernovae (SNe), so far only four pairs of GRBs and SNe with firmly…
Search for strong gravitational lensing effect in the current GRB data of BATSE
Chun-Yu Li, Li-Xin Li
Because gamma-ray bursts (GRBs) trace the high-z Universe, there is an appreciable probability for a GRB to be gravitational lensed by galaxies in the universe. Herein we consider…
Jet Collimation by Small-Scale Magnetic Fields
Li-Xin Li
A popular model for jet collimation is associated with the presence of a large-scale and predominantly toroidal magnetic field originating from the central engine (a star, a black…
Constraining fast radio burst progenitors with gravitational lensing
Chun-Yu Li, Li-Xin Li
Fast Radio Bursts (FRBs) are new transient radio sources discovered recently. Because of the angular resolution restriction in radio surveys, no optical counter part has been ident…
Improved Correlation between the Variability and Peak Luminosity of Gamma-Ray Bursts
Li-Xin Li, Bohdan Paczynski
A new procedure for smoothing a gamma-ray burst (GRB) lightcurve and calculating its variability is presented. Applying the procedure to a sample of 25 long GRBs, we have obtained…
Neutron Star Mergers as the Dominant Contributor to the Production of Heavy -Process Elements
Meng-Hua Chen, Li-Xin Li, Qiu-Hong Chen +2
The discovery of the radioactively powered kilonova AT2017gfo, associated with the short-duration gamma-ray burst GRB 170817A and the gravitational wave source GW170817, has provid…
Accretion, Growth of Supermassive Black Holes, and Feedback in Galaxy Mergers
Li-Xin Li
Super-Eddington accretion is very efficient in growing the mass of a black hole: in a fraction of the Eddington time its mass can grow to an arbitrary large value if the feedback e…
Must Time Machine Be Unstable against Vacuum Fluctuations?
Li-Xin Li
In the appearance of absorption material, the quantum vacuum fluctuations of all kinds of fields may be smoothed out and the spacetime with time machine may be stable against vacuu…
Thermodynamics and Holographic RG Flow in 3D C-metric
Shaohua Xue, Yingyu Yang, Li-Xin Li
In this paper, we investigate the microscopic derivation of the entropy and the holographic RG flow in 3D C-metric. We first discuss the case of a sector in BTZ (Banados-Teitelboim…
A New Unified Theory of Electromagnetic and Gravitational Interactions
Li-Xin Li
In this paper we present a new unified theory of electromagnetic and gravitational interactions. By considering a four-dimensional spacetime as a hypersurface embedded in a five-di…
The Spin of the Near-Extreme Kerr Black Hole GRS 1915+105
Jeffrey E. McClintock, Rebecca Shafee, Ramesh Narayan +3
Based on a spectral analysis of the X-ray continuum that employs a fully relativistic accretion-disk model, we conclude that the compact primary of the binary X-ray source GRS 1915…
Are Gamma-Ray Bursts a Standard Energy Reservoir?
Li-Xin Li
One of the most important discoveries in the observation of gamma-ray bursts (GRBs) is that the total energy emitted by a GRB in gamma-rays has a very narrow distribution around 10…
Star Formation History up to z = 7.4: Implications for Gamma-Ray Bursts and the Cosmic Metallicity Evolution
Li-Xin Li
The current Swift sample of gamma-ray bursts (GRBs) with measured redshifts allows to test the assumption that GRBs trace the star formation in the Universe. Some authors have clai…
Radioactive Gamma-Ray Lines from Long-lived Neutron Star Merger Remnants
Meng-Hua Chen, Li-Xin Li, En-Wei Liang
The observation of a kilonova AT2017gfo associated with the gravitational wave event GW170817 provides the first strong evidence that neutron star mergers are dominant contributors…
Effect of the Global Rotation of the Universe on the Formation of Galaxies
Li-Xin Li
The effect of the global rotation of the universe on the formation of galaxies is investigated. It is found that the global rotation provides a natural origin for the rotation of g…
The GRB-Supernova Connection
Li-Xin Li
Long-duration gamma-ray bursts (GRBs) are believed to be produced by the core collapse of massive stars and hence to be connected with supernovae (SNe). Indeed, for four pairs of G…
Gravitational Lensing by a Compound Population of Halos: Standard Models
Li-Xin Li, Jeremiah P. Ostriker
Based on observed rotation curves of galaxies and theoretical simulations of dark matter halos, there are reasons for believing that at least three different types of dark matter h…
Two Open Universes Connected by a Wormhole: Exact Solutions
Li-Xin Li
In this paper I present a spacetime of two open universes connected by a Lorentzian wormhole. The spacetime has the following features: (1) It can exactly solve the Einstein equati…
Probability for chance coincidence of a gamma-ray burst with a galaxy on the sky
Maria Angela Campisi, Li-Xin Li
The nearby long GRB 060614 was not accompanied by a supernova, challenging the collapsar model for long-duration GRBs and the traditional classification scheme for GRBs. However, C…
Time Machines Constructed from Anti-de Sitter Space
Li-Xin Li
In this paper time machines are constructed from anti-de Sitter space. One is constructed by identifying points related via boost transformations in the covering space of anti-de S…
Line Expansion Opacity in Relativistically Expanding Media
Li-Xin Li
Spectral lines of heavy atomic elements in the ejecta of supernovae and neutron star mergers can have important contribution to the opacity of the ejecta matter even when the abund…
Shock Breakout in Type Ibc Supernovae and Application to GRB 060218/SN 2006aj
Li-Xin Li
Recently, a soft black-body component was observed in the early X-ray afterglow of GRB 060218, which was interpreted as shock breakout from the thick wind of the progenitor Wolf-Ra…
Are Gamma-Ray Bursts Standard Candles?
Li-Xin Li
By dividing a sample of 48 long-duration gamma-ray bursts (GRBs) into four groups with redshift from low to high and fitting each group with the Amati relation log Eiso = a + b log…
Simulating Kilonovae in the ÎCDM Universe
Zhen Jiang, Jie Wang, Fenghui Zhang +6
Kilonovae are optical flashes produced in the aftermath of neutron star-neutron star mergers (NNMs) or neutron star-black hole mergers (NBMs). In this work, we use the Millennium S…
Electrodynamics on Cosmological Scales
Li-Xin Li
Maxwell's equations cannot describe a homogeneous and isotropic universe with a uniformly distributed net charge, because the electromagnetic field tensor in such a universe must b…
Can Temperature Be Quantized?
Li-Xin Li
It is shown that the temperature may be quantized in some spacetime due to the periodically topological structure of the Euclidean section. The quanta of the temperature is the Haw…
Can the Universe Create Itself?
J. Richard Gott, III, Li-Xin Li
The question of first-cause has troubled philosophers and cosmologists alike. Now that it is apparent that our universe began in a Big Bang explosion, the question of what happened…
Variation of the Amati Relation with the Cosmological Redshift: a Selection Effect or an Evolution Effect?
Li-Xin Li
Because of the limit in the number of gamma-ray bursts (GRBs) with available redshifts and spectra, all current investigations on the correlation among GRB variables use burst samp…
Screw Instability and Blandford-Znajek Mechanism
Li-Xin Li
When magnetic field lines thread a rotating black hole's horizon and connect with remote astrophysical loads, the rotational energy of the black hole can be extracted through the B…
Accretion Disk Torqued by a Black Hole
Li-Xin Li
If a Kerr black hole is connected to a disk rotating around it by a magnetic field, the rotational energy of the Kerr black hole provides an energy source for the radiation of the…
Estimating the Spin of Stellar-Mass Black Holes via Spectral Fitting of the X-ray Continuum
Rebecca Shafee, Jeffrey E. McClintock, Ramesh Narayan +3
We fit X-ray spectral data in the thermal dominant or high soft state of two dynamically confirmed black holes, GRO J1655-40 and 4U 1543-47, and estimate the dimensionless spin par…
Disk Accretion Flow Driven by Large-Scale Magnetic Fields: Solutions with Constant Specific Energy
Li-Xin Li
(Abridged) We study the dynamical evolution of a stationary, axisymmetric, and perfectly conducting cold accretion disk containing a large-scale magnetic field around a Kerr black…
Extracting Energy from Black Hole through Transition Region
Li-Xin Li
A new scenario for extracting energy from a Kerr black hole is proposed. With magnetic field lines connecting plasma particles inside the ergosphere with remote loads, the frame dr…
Energetics of Black Hole-Accretion Disk System with Magnetic Connection: Limit of Low Accretion Rate
Li-Xin Li
We study the energetics of a black hole-accretion disk system with magnetic connection: a Keplerian disk is connected to a Kerr black hole by a large-scale magnetic field going thr…
Vacuum Polarization in an Anti-de Sitter Space as an Origin for a Cosmological Constant in a Brane World
Li-Xin Li
In this Letter we show that the vacuum polarization of quantum fields in an anti-de Sitter space naturally gives rise to a small but nonzero cosmological constant in a brane world…
Impact of nuclear mass models on -process nucleosynthesis and heavy element abundances in -process enhanced metal-poor stars
Meng-Hua Chen, Li-Xin Li, En-Wei Liang +1
Due to the lack of experimental data on extremely neutron-rich nuclei, theoretical values derived from nuclear physics models are essential for the rapid neutron capture process ($…
Non-Axisymmetric g-Mode and p-Mode Instability in a Hydrodynamic Thin Accretion Disk
Li-Xin Li, Jeremy Goodman, Ramesh Narayan
It has been suggested that quasi-periodic oscillations of accreting X-ray sources may relate to the modes named in the title. We consider non-axisymmetric linear perturbations to a…
Transient Events from Neutron Star Mergers
Li-Xin Li, Bohdan PaczyÅski
Mergers of neutron stars (NS+NS) or neutron stars and stellar mass black holes (NS+BS) eject a small fraction of matter with a sub-relativistic velocity. Upon rapid decompression n…
Redshift Degeneracy in the Eiso-Epeak Relation of Gamma-Ray Bursts
Li-Xin Li
In this Letter we show that there is a redshift degeneracy in the Eiso-Epeak relation of gamma-ray bursts (GRBs). If a GRB has a redshift solved from the Eiso-Epeak relation that l…
C2H N=1-0 and N2H+ J=1-0 observations of Planck Galactic cold clumps
Xunchuan Liu, Yuefang Wu, Chao Zhang +5
A survey of C2H N=1-0 and N2H+ J=1-0 toward Planck Galactic cold clumps (PGCCs) was performed using the Purple Mountain Observatory's 13.7 m telescope. C2H and N2H+ were chosen to…
Electromagnetic Force on a Brane
Li-Xin Li
A fundamental assumption in the theory of brane world is that all matter and radiation are confined on the four-dimensional brane and only gravitons can propagate in the five-dimen…
Extracting Energy from Accretion into Kerr Black Hole
Li-Xin Li, Bohdan Paczynski
The highest efficiency of converting rest mass into energy by accreting matter into a Kerr black hole is ~ 31% (Thorne 1974). We propose a new process in which periods of accretion…
The Marginally Stable Circular Orbit of the Fluid Disk around a Black Hole
Lei Qian, Xue-Bing Wu, Li-Xin Li
The inner boundary of a black hole accretion disk is often set to the marginally stable circular orbit (or the innermost stable circular orbit, ISCO) around the black hole. It is i…
The Giant X-Ray Flare of NGC 5905: Tidal Disruption of a Star, a Brown Dwarf, or a Planet?
Li-Xin Li, Ramesh Narayan, Kristen Menou
We model the 1990 giant X-ray flare of the quiescent galaxy NGC 5905 as the tidal disruption of a star by a supermassive black hole. From the observed rapid decline of the luminosi…
A Toy Model for the Magnetic Connection between a Black Hole and a Disk
Li-Xin Li
A magnetic field connecting a Kerr black hole to a disk rotating around it can extract energy and angular momentum from the black hole and transfer them to the disk if the black ho…
Correlation between the Peak Spectral Energy of Gamma-Ray Bursts and the Peak Luminosity of the Underlying Supernovae: Implication for the Nature of GRB-SN Connection
Li-Xin Li
In this paper we present a correlation between the peak spectral energy of gamma-ray bursts (GRBs) and the peak bolometric luminosity of the underlying supernovae (SNe), based on a…