Blogs
Make a little progress every day.
2024
Nov 31, Sun
- Wrote my PhD thesis.
Nov 29, Fri
- Discussed with Prof. Bin Chen, Yehui Hou and Yu Song about the paper arXiv:2410.00954.
Nov 27, Wed
- Wrote my PhD thesis.
Nov 26, Tue
- Wrote my PhD thesis.
Nov 25, Mon
- Discussed with Prof. Bin Chen.
Nov 24, Sun
- Wrote my PhD thesis.
Nov 23, Sat
- Wrote my PhD thesis.
Nov 21, Thu
- Finished the code for supplementary research.
Nov 20, Wed
- Did some supplementary research about the paper mentioned yesterday.
Nov 19, Tue
- Discussed with Yehui Hou and Yu Song about the review comments on the hotspot polarization imaging paper 2407.14897.
Nov 18, Mon
Went to BNU and listened to the talk of Minyuan Zhang from TDLI.
The BHAC code seems to be slow with gfortran. Tried to use ifort.
Nov 17, Sun
- Discussed with Wencong Hong about the PBH abundance calculation.
Nov 14, Thu
- Wrote my PhD thesis.
Nov 13, Wed
- Began to run BHAC.
Nov 12, Tue
- Tried to run BHAC in PKU’s supercomputing platform.
Nov 11, Mon
- Went back to Beijing.
Nov 10, Sun
Gave the talk about the autocorrelation of black hole movies.
Discussed with many people.
Nov 9, Sat
Attended the workshop and listened to the presentations.
Prepared the talk.
Nov 8, Fri
- Arrived Changsha, Hunan.
Nov 6, Wed
- Prepared the presentation for the upcoming black hole imaging workshop in Changsha, Hunan.
Nov 5, Tue
- Discussed with Yehui Hou and Yu Song about the review comments on the hotspot polarization imaging paper 2407.14897.
Nov 4, Mon
- Attended the group meeting of Prof. Shi Pi.
Oct 28, Mon
- Attended the group meeting of Prof. Shi Pi.
Oct 27, Sun
- Wrote the autocorrelation note.
Oct 26, Sat
- Went to the national museum with my wife.
Oct 25, Fri
- Ajusted the result figures in the autocorrelation note.
Oct 24, Thu
- Obtained the fixed point.
Oct 23, Wed
- Read the relevant papers and wrote the autocorrelation note.
Oct 22, Tue
- Wrote the autocorrelation note.
Oct 21, Mon
- Attend the group meeting of Prof. Minyong Guo and gave an informal talk.
Oct 20, Sun
- Wrote the autocorrelation note.
Oct 19, Sat
- Took a rest due to ailment.
Oct 18, Fri
Attended a seminar by Prof. Sébastien Clesse at ITP, CAS. The title was “could primordial black holes with an extended mass distribution explain the dark matter and gravitational-wave observations”.
Discussed with Yu Song about the binary shadow project.
Oct 17, Thu
- Discussed with Prof. Bin Chen, Prof. Minyong Guo, Yehui Hou and Yu Song about on-going projects and future plans.
Oct 16, Wed
- Tried to acheive the place of the fixed points in autocorrelation figures using Python.
Oct 15, Tue
- Attended the group meeting of Prof. Shi Pi.
Oct 14, Mon
- Prepared application materials.
Oct 13, Sun
- Started to write the note for the autocorrelation project.
Oct 12, Sat
- Prepared application materials.
Oct 11, Fri
- Discussed with Prof. Minyong Guo and Yehui Hou about the autocorrelation project.
Oct 10, Thu
- Read the note of the binary shadow written by Yu Song.
Oct 9, Wed
- Discussed with Xiangyu Wang about MCMC.
Oct 8, Tue
- Prepared application materials.
Oct 7, Mon
Prepared application materials.
Thought about the reason for the immobility points.
Oct 6, Sun
- Finished producing preliminary results of the autocorrelation project.
Oct 5, Sat
Continued producing the autocorrelation results for subsequent physical analysis.
Struggled with application materials.
Oct 4, Fri
Continued producing the autocorrelation results for subsequent physical analysis.
Struggled with application materials.
Oct 3, Thu
Discussed with Prof. Minyong Guo and Yehui Hou about the physical explanation of the autocorrelation results.
Prepared application materials.
Oct 2, Wed
- Organized the results of the hotspot autocorrelation. The position of the fixed point shows some deviation from the theoretical calculation in 2010.03683. It is speculated that this may be due to the secondary image being insufficient for applying the near-photon ring approximation.
Oct 1, Tue
- Calculated autocorrelation for different radius hotspots.
Sept 30, Mon
- Discussed with Prof. Minyong Guo about the autocorrelation results.
Sept 29, Sun
- Translated the autocorrelation calculation code from python into C. The speed is dozens of times faster than before.
Sept 28, Sat
- Obtained some interesting results about the hotspot autocorrelation. The effect of secondary image was shown.
Sept 27, Fri
- Finished the code mentioned yesterday and started to run the code.
Sept 26, Thu
- Improved the inoisy raytracing code to speed up.
Sept 25, Wed
- Found a bug of the non-equatorial hotspot raytracing code.
Sept 24, Tue
Conceived the PhD thesis.
Prepared application materials.
Sept 23, Mon
- Ran raytracing code for different radius hotspots on the workstation in the office.
Sept 22, Sun
- Finished the code mentioned yesterday.
Sept 21, Sat
- Tried to write a mathematica raytracing code for inoisy.
Sept 20, Fri
- Discussed with Zhixing Zhao about hotspot raytracing.
Sept 19, Thu
Attended the group meeting of Prof. Bin Chen. The speaker of this time was Zezhou Hu. He talked about Carrollian superstring theory.
Discussed with Prof. Minyong Guo about the autocorrelation project.
Sept 18, Wed
- Tried to calculate the autocorrelation of a hotspot movie.
Sept 17, Tue
- Prepared postdoc application materials.
Sept 16, Mon
- Did housework for a whole day.
Sept 15, Sun
- Did housework for a whole day.
Sept 14, Sat
- Discussed with Xinyu Wang about the PA defined in EHT’s papers.
Sept 13, Fri
- Attended the group meeting of Prof. Shi Pi.
Sept 12, Thu
- Tried to trace the source position of the three balls.
Sept 11, Wed
- Attended the group meeting of Prof. Bin Chen. The speaker of this time was Yu Song. He mainly talked about nonlinear photon-plasma interaction and the black hole superradiant instability in the paper 2306.12490.
Sept 10, Tue
- Calculated the three local maximum of the Sgr A* intensity data.
Sept 9, Mon
- Discussed with Xinyu Wang about the three-ball project. Tranferred the Sgr A* image into data using Python.
Sept 8, Sun
- Wrote a code for generate hotspot movie by the intensity data. Tried to obtain the intensity data of the EHT Sgr A* observation.
Sept 7, Sat
- Wrote a code for imaging arbitrary orbital hotspot light sources.
Sept 6, Fri
Set up remote control for the computer in the office. Configured the environment for the inoisy code in that computer.
Attended the group meeting of Prof. Shi Pi.
Sept 5, Thu
Discussed with Prof. Bin Chen, Prof. Minyong Guo and Yehui Hou about the business trip to Shanghai.
Discussed with Xinyu Wang about the three-ball idea.
Sept 4, Wed
Attended the group meeting of Prof. Bin Chen. The speaker of this time was Ho-Yun YuChih. She mainly talked about the energy extraction from a Kerr black hole via magnetic reconnection.
Ran the raytracing code for the hotspot movie.
Sept 3, Tue
- Struggled with the autocorrelation project. I changed the inoisy code to generate the SU’s envelope data.
Sept 2, Mon
- Struggled with the autocorrelation project. I found that Eq. (99) mentioned in 2211.07469 is not included in the publicly available inoisy or AART code, so I need to generate the envelope data from the raw data myself.
Sept 1, Sun
Wrote a code about the idea mentioned yesterday.
Started to do some work about the three-ball model.
Aug 31, Sat
- Came up with a hotspot imaging approach.
Aug 30, Fri
- Attended the group meeting of Prof. Shi Pi.
Aug 29, Thu
- Went back to Beijing. Tried again to incorporate non-Gaussianity into the SIGW code.
Aug 28, Wed
Discussed with Prof. Yosuke Mizuno and Prof. Minyong Guo about the autocorrelation project. We proposed some specific light sources to calculate.
Discussed with Yehui Hou. He found that the Eq.(8) in 2304.03826 seems to be wrong.
Aug 27, Tue
- Worked and discussed at TDLI, SJTU. Prof. Minyong Guo gave a talk about Coport. They expressed some concern about the case of opitically thick, because the affine paramter need to be divided smaller in the emisson region. After that, we had a dinner with Prof. Yosuke Mizuno.
Aug 26, Mon
- Visited TDLI, SJTU. Learned a lot from Prof. Yosuke Mizuno. He is a knowledgeable and hospitable person with a passion for academia. We also discussed with his group members. I talked about our previous papers and now the preliminary results of autocorrelation. There are still many open questions about the image of Sgr A*.
Aug 25, Sun
- Arrived Shanghai. Finished the autocorrelation code and partly reproduced the result of 2304.03826.
Aug 24, Sat
- Attempted to numerical calculate autocorrelation function using Python.
Aug 23, Fri
- Attended the group meeting of Prof. Shi Pi. He told me that factor of 2 comes from the two polarization modes of the GW.
Aug 22, Thu
- Struggled with the quadruple integral.
Aug 21, Wed
- Attempted to incorporate non-Gaussianity into the SIGW code. I found that the adaptive Monte Carlo method can be used to compute the quadruple integral.
Aug 20, Tue
- Attended the group meeting of Prof. Bin Chen. The speaker of this time was Zhenbang Gu. He talked about some mathematical physics. I could barely understand a word of it.
Aug 19, Mon
- Discussed high-order polarized imaging of thin disk with Yu Song.
Aug 18, Sun
- Revised the paper 2407.14897 and submitted the new version to arXiv.
Aug 17, Sat
- Struggled with a SIGW problem. Based on my derivation, Eq. (3) in 2306.17149 and Eq. (83) in 2404.06151 differ by a factor of 2, but I can’t find where I went wrong.
Aug 16, Fri
- Attended the group meeting of Prof. Shi Pi. Discussed the calculation of primordial black hole abundance with Ao Wang. He believes that both the effects of a broad power spectrum and the shape parameter q can be incorporated into the Press-Schechter method. Actually, I had considered a similar issue last year, so I expressed pessimism. I roughly learned from Wencong Hong how to obtain the sensitivity curve from LIGO gravitational wave data. I also roughly learned from Prof. Pi how weak lensing constrains the abundance of primordial black holes.
Aug 15, Thu
Reorganized the code about thin disk imaging.
Learned something about quasinormal modes. Basically, it involves setting the ingoing and outgoing boundary conditions at the black hole horizon and at infinity, and solving the equations of motion for the perturbation field in the curved spacetime. This approach is feasible because when a field does not have a backreaction on the background, the perturbation in the black hole spacetime simplifies to the propagation of the field in the black hole background. The observational significance is that the QNM will dominate the ringdown phase of the gravitational wave signal. The ringdown refers to the process of the BH gradually become stable after the merger.
Aug 14, Wed
Attended the group meeting of Prof. Bin Chen. The speaker of this time was Zezhou Hu. He talked about Carrollian superstring theory.
Read an interesting paper about autocorrelation, 2304.03826. The authors selected a circle in the black hole movie that approximates the location of photon ring (as defined by Eq. (1) (2)) and calculated the 1+1 dimensional autocorrelation along this line. They claimed that the pattern speed can be obtained through this 2D autocorrelation, as detailed in the last paragraph of Sec. 2.2. Subsequently, they validated the method’s accuracy using some synthetic light sources. Finally, they applied it to the GRMHD model library of Sgr A*.
Aug 13, Tue
Aug 12, Mon
Learned the basics of using PKU’s supercomputing platform.
Discussed high-order polarized imaging of thin disk with Yu Song. The main references are 1602.03184, 2206.13744 and 2407.10431.