4,109 research outputs found
An Application of Lorentz Invariance Violation in Black Hole Thermodynamics
In this paper, we have applied the Lorentz-invariance-violation (LIV) class
of dispersion relations (DR) with the dimensionless parameter n = 2 and the
"sign of LIV" {\eta}_+ = 1, to phenomenologically study the effect of quantum
gravity in the strong gravitational field. Specifically, we have studied the
effect of the LIV-DR induced quantum gravity on the Schwarzschild black hole
thermodynamics. The result shows that the effect of the LIV-DR induced quantum
gravity speeds up the black hole evaporation, and its corresponding black hole
entropy undergoes a leading logarithmic correction to the "reduced
Bekenstein-Hawking entropy", and the ill defined situations (i.e. the
singularity problem and the critical problem) are naturally bypassed when the
LIV-DR effect is present. Also, to put our results in a proper perspective, we
have compared with the earlier findings by another quantum gravity candidate,
i.e. the generalized uncertainty principle (GUP). Finally, we conclude from the
inert remnants at the final stage of the black hole evaporation that, the GUP
as a candidate for describing quantum gravity can always do as well as the
LIV-DR by adjusting the model-dependent parameters, but in the same
model-dependent parameters the LIV-DR acts as a more suitable candidate.Comment: 18 pages, 7 figure
Hawking radiation from (2+1)-dimensional BTZ black holes
Motivated by the Robinson-Wilczek's recent viewpoint that Hawking radiation
can be treated as a compensating energy momentum tensor flux required to cancel
gravitational anomaly at the horizon of a Schwarzschild-type black hole, we
investigate Hawking radiation from the rotating -dimensional BTZ black
hole and the charged -dimensional BTZ black hole, via cancellation of
gauge and gravitational anomalies at the horizon. To restore gauge invariance
and general coordinate covariance at the quantum level, one must introduce the
corresponding gauge current and energy momentum tensor fluxes to cancel gauge
and gravitational anomalies at the horizon. The results show that the values of
these compensating fluxes are exactly equal to those of -dimensional
blackbody radiation at the Hawking temperature.Comment: 15 pages; references updated and added; to appear in Phys. Lett.
PACF: A precision-adjustable computational framework for solving singular values
Singular value decomposition (SVD) plays a significant role in matrix analysis, and the differential quotient difference with shifts (DQDS) algorithm is an important technique for solving singular values of upper bidiagonal matrices. However, ill-conditioned matrices and large-scale matrices may cause inaccurate results or long computation times when solving singular values. At the same time, it is difficult for users to effectively find the desired solution according to their needs. In this paper, we design a precision-adjustable computational framework for solving singular values, named PACF. In our framework, the same solution algorithm contains three options: original mode, high-precision mode, and mixed-precision mode. The first algorithm is the original version of the algorithm. The second algorithm is a reliable numerical algorithm we designed using Error-free transformation (EFT) technology. The last algorithm is an efficient numerical algorithm we developed using the mixed-precision idea. Our PACF can add different solving algorithms for different types of matrices, which are universal and extensible. Users can choose different algorithms to solve singular values according to different needs. This paper implements the high-precision DQDS and mixed-precision DQDS algorithms and conducts extensive experiments on a supercomputing platform to demonstrate that our algorithm is reliable and efficient. Besides, we introduce the error analysis of the inner loop of the DQDS and HDQDS algorithms
Anomalies and de Sitter radiation from the generic black holes in de Sitter spaces
Robinson-Wilczek's recent work shows that, the energy momentum tensor flux
required to cancel gravitational anomaly at the event horizon of a
Schwarzschild-type black hole has an equivalent form to that of a
(1+1)-dimensional blackbody radiation at the Hawking temperature. Motivated by
their work, Hawking radiation from the cosmological horizons of the general
Schwarzschild-de Sitter and Kerr-de Sitter black holes, has been studied by the
method of anomaly cancellation. The result shows that the absorbing gauge
current and energy momentum tensor fluxes required to cancel gauge and
gravitational anomalies at the cosmological horizon are precisely equal to
those of Hawking radiation from it. It should be emphasized that the effective
field theory for generic black holes in de Sitter spaces should be formulated
within the region between the event horizon (EH) and the cosmological horizon
(CH), to integrate out the classically irrelevant ingoing modes at the EH and
the classically irrelevant outgoing modes at the CH, respectively.Comment: 14 pages without figure, use elsart.cls, to appear in Phys.Lett.
Recommended from our members
Dual blockage of STAT3 and ERK1/2 eliminates radioresistant GBM cells.
Radiotherapy (RT) is the major modality for control of glioblastoma multiforme (GBM), the most aggressive brain tumor in adults with poor prognosis and low patient survival rate. To improve the RT efficacy on GBM, the mechanism causing tumor adaptive radioresistance which leads to the failure of tumor control and lethal progression needs to be further elucidated. Here, we conducted a comparative analysis of RT-treated recurrent tumors versus primary counterparts in GBM patients, RT-treated orthotopic GBM tumors xenografts versus untreated tumors and radioresistant GBM cells versus wild type cells. The results reveal that activation of STAT3, a well-defined redox-sensitive transcriptional factor, is causally linked with GBM adaptive radioresistance. Database analysis also agrees with the worse prognosis in GBM patients due to the STAT3 expression-associated low RT responsiveness. However, although the radioresistant GBM cells can be resensitized by inhibition of STAT3, a fraction of radioresistant cells can still survive the RT combined with STAT3 inhibition or CRISPR/Cas9-mediated STAT3 knockout. A complementally enhanced activation of ERK1/2 by STAT3 inhibition is identified responsible for the survival of the remaining resistant tumor cells. Dual inhibition of ERK1/2 and STAT3 remarkably eliminates resistant GBM cells and inhibits tumor regrowth. These findings demonstrate a previously unknown feature ofSTAT3-mediated ERK1/2 regulation and an effective combination of two targets in resensitizing GBM to RT
Twenty-six circulating antigens and two novel diagnostic candidate molecules identified in the serum of canines with experimental acute toxoplasmosis
List of CAg proteins identified by LC-MS/MS after IP enrichment and purification with ESA antibodies. (XLSX 27 kb
Recommended from our members
Genome Composition and Divergence of the Novel Coronavirus (2019-nCoV) Originating in China.
An in-depth annotation of the newly discovered coronavirus (2019-nCoV) genome has revealed differences between 2019-nCoV and severe acute respiratory syndrome (SARS) or SARS-like coronaviruses. A systematic comparison identified 380 amino acid substitutions between these coronaviruses, which may have caused functional and pathogenic divergence of 2019-nCoV
- …