You can find my most recent publications at my INSPIRE profile.

Probing new physics with compact objects

While terrestrial experiments have been very successful in establishing the standard model of physics, astrophysical compact objects, such as pulsars and black holes, serve as powerful natural labs for probing new physics on high-energy/density scales. These objects are dense and ubiquitous in the universe, often accompanied by extreme conditions like very high temperatures and intense magnetic fields. I am interested in exploring how these extreme conditions affect matter and fundamental forces, aiming to discover potential observable signatures they could imprint.

Dark matter theory and phenomenology

Ordinary matter constitutes a mere 16% of total matter in our universe, with the remaining 84% designated as dark matter. I seek to unveil the nature of dark matter by using the tools of cosmology, astrophysics and particle physics. Some key questions I would like to address include:

  • How does dark matter form, evolve and finally lead to our present-day universe?
  • How does dark matter interact with itself, ordinary matter and gravity?
  • How to detect it?

To help answer these questions, I developed effective field theory and studied the interaction of dark matter via nontopological solitons, neutron stars, structure formation, gravitational waves, etc. Some of the techniques developed during my research can also be used for other areas such as axions and modified gravity.

Nonlinear dynamics and physics of solitons

The existence of solitons—stable, long-lived, and localized field configurations—is a generic prediction in many important physical scenarios, such as cosmic inflation and ultralight dark matter. They are also excellent targets for exploring the mathematical aspects of nonlinear dynamics. My research aims to understand:

  • Nonlinear properties of a single soliton, including decay rates, polarization, quantum and general relativity effects, etc.
  • The interactions between solitons and their surrounding environments.
  • Applications of solitons in physics. For examples, they could form during the structure formation of our universe.

Here are some “photos” of vector solitons from 3+1-dimensional simulations [arXiv:2111.08700]:

Picture Picture Picture

Extremally polarized (left two) and hedgehog (right) vector solitons. The arrows stand for the magnitude and direction of the 3-vector (i.e., spatial part), and the color represents the energy density. In the nonrelativistic limit, the average spin per particle is 0 in linearly polarized (left) and hedgehog (right) solitons, and 1 in circularly polarized configurations (middle).

Useful tools

  • I developed the Mathematica package UnitConversion that allows the conversion of quantities between standard and natural units. Try it and free your hands!
  • I developed the Mathematica package DMSolitonFinder that solves dark matter soliton profiles, which has been featured in the Staff Picks and Publication Materials columns on Wolfram Community.

Research note