3,071 research outputs found
Emergent conformal symmetry for black holes without symmetry
We investigate the motion of the massless scalar field and the nearly bound
null geodesic in the near-ring region of a black hole with either acceleration
or Misner charge, around which the photon ring deviates from the equatorial
plane. In the eikonal limit, we demonstrate that the massless scalar field
exhibits an emergent conformal
algebra in the near-ring region. Additionally, in the nearly bound limit, we
observe the emergence of an
conformal algebra for the null geodesics that form the photon ring in the black
hole image. Our findings indicate that the emergent conformal symmetry persists even for black holes without
symmetry, thus expanding the foundations of photon ring
holography.Comment: 21 page
Multi-chromatic narrow-energy-spread electron bunches from laser wakefield acceleration with dual-color lasers
A method based on laser wakefield acceleration with controlled ionization
injection triggered by another frequency-tripled laser is proposed, which can
produce electron bunches with low energy spread. As two color pulses
co-propagate in the background plasma, the peak amplitude of the combined laser
field is modulated in time and space during the laser propagation due to the
plasma dispersion. Ionization injection occurs when the peak amplitude exceeds
certain threshold. The threshold is exceeded for limited duration periodically
at different propagation distances, leading to multiple ionization injections
and separated electron bunches. The method is demonstrated through
multi-dimensional particle-in-cell simulations. Such electron bunches may be
used to generate multi-chromatic X-ray sources for a variety of applications.Comment: 5 pages, 5 figures; accepted by PR
Positive-partial-transpose distinguishability for lattice-type maximally entangled states
We study the distinguishability of a particular type of maximally entangled
states -- the "lattice states" using a new approach of semidefinite program.
With this, we successfully construct all sets of four ququad-ququad orthogonal
maximally entangled states that are locally indistinguishable and find some
curious sets of six states having interesting property of distinguishability.
Also, some of the problems arose from \cite{CosentinoR14} about the
PPT-distinguishability of "lattice" maximally entangled states can be answered.Comment: It's rewritten. We deleted the original section II about
PPT-distinguishability of three ququad-ququad MESs. Moreover, we have joined
new section V which discuss PPT-distinguishability of lattice MESs for cases
and . As a result, the sequence of the theorems in our article
has been changed. And we revised the title of our articl
Efficient generation of relativistic near-single-cycle mid-infrared pulses in plasmas
Ultrashort intense optical pulses in the mid-infrared (mid-IR) region are very important for broad applications ranging from super-resolution spectroscopy to attosecond X-ray pulse generation and particle acceleration. However, currently, it is still difficult to produce few-cycle mid-IR pulses of relativistic intensities using standard optical techniques. Here, we propose and numerically demonstrate a novel scheme to produce these mid-IR pulses based on laser-driven plasma optical modulation. In this scheme, a plasma wake is first excited by an intense drive laser pulse in an underdense plasma, and a signal laser pulse initially at the same wavelength (1 micron) as that of the drive laser is subsequently injected into the plasma wake. The signal pulse is converted to a relativistic multi-millijoule near-single-cycle mid-IR pulse with a central wavelength of ~5 microns via frequency-downshifting, where the energy conversion efficiency is as high as approximately 30% when the drive and signal laser pulses are both at a few tens of millijoules at the beginning. Our scheme can be realized with terawatt-class kHz laser systems, which may bring new opportunities in high-field physics and ultrafast science
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