zhi

Curriculum Vitae

Fri, 22 May 2026 00:00:00 -0400

</ox-hugo/cv.pdf>

about

Thu, 30 Jan 2025 00:00:00 -0500

Figure 1: This is Nian Nian.

Hi there! I am a graduate student in astrophysics at Stony Brook University . I work with Michael Zingale on the development of numerical algorithms and their applications in modeling astrophysical thermonuclear explosion events, such as X-ray bursts.

Beyond academia, I enjoy playing fingerstyle guitar, reading manga, working on hands-on projects, and relaxing with my cat, NianNian.

Feel free to reach out to me at zhi.chen.3@stonybrook.edu .

GDB Tutorial

Tue, 14 Apr 2026 00:00:00 -0400

GDB , the GNU Project debugger, is a useful debugger for many languages (C, C++, Fortran, etc). Here I keep a set of useful commands for my records.

Using GDB

To use GDB, compile the program with debugging information. For standard C++ program, add -g flag when compiling, i.e. something like

g++ -g -o myprogram myprogram.cpp

For AMReX related application codes like Castro, compile with DEBUG=TRUE, i.e.

make DEBUG=TRUE

Now launch GDB with compiled program as the following.

Using ox-Hugo

Sat, 17 Jan 2026 00:00:00 -0500

Hugo is a static website generator written with GO, providing easily capability to convert markdown files into a website. For those who use emacs Org mode , one can use ox-hugo to convert Org files into markdown files that will be compatible with Hugo. Hence the workflow is:

\[\mathrm{Org} \\ \xrightarrow{\text{ox-hugo}} \\ \mathrm{markdown} \\ \xrightarrow{\text{Hugo}} \\ \mathrm{HTML}\]

For me, I use it to create my research journal and personal website.

Here I describe different ways of writing things in Org mode that can be re-interpreted by ox-hugo to generate the corresponding md files that can be used by Hugo for my own records.

Sensitivity of He Flames in X-ray Bursts to Nuclear Physics

Sun, 02 Feb 2025 00:00:00 -0500

Introduction

Millisecond burst oscillation phenomenon is often observed during the rise time of the X-ray burst light curve, where the oscillation frequency matches with the X-ray emission pulsation of the neutron star within few Hz. The modulation of asymmetrical burning on the surface of the neutron star due to the spreading of the initial local hotspot is the current contender theory that explains this behavior. Many have attempted to model the laterally flame propagation on the neutron star surface, with successes at studying the flame front and calculating the flame speed. In this project, I conducted a sensitivity test on how choices of nuclear reaction network, plasma screening routines, and integration coupling methods can influence the He flame dynamics. Details of the work is published in ApJ . Here I’ll just summarize the most important finding on the effect of nuclear reaction network on flame dynamics and nucleosynthesis.

Interferometry

Sun, 02 Feb 2025 00:00:00 -0500

This was my research project during my SULI internship in 2021. I was interested in estimating the precision of the two-photon interferometry technique for measuring the relative separation between two light-sources (i.e. stars) using Markov-Chain Monte Carlos (MCMC) simulation.

Two-photon Interferometer Overview

Assume there are two sources which can be observed simultaneously from two stations, L and R , with single spatial mode inputs a, b and e, f. Both sources send out photons in the form of plane wave, the path length difference between the two stations yielding phase delays \(\delta_1\) and \(\delta_2\) between the photons observed at channels a, e from source 1 and b, f from source 2, respectively. If the two detected photons are close enough in frequency and arrival time, then the pattern of coincidences measured at the outputs c, d and g, h will be sensitive to the difference in phase delays after interference at the symmetric beam splitter in each station.