Plasma physics in relativistic and quantum regimes
Quantum field theories are powerful tools for particle physics and condensed matter physics but are rarely used in plasma physics. However, in warm-dense regimes, where matter is partially ionized and strongly correlated, quantum effects are important. The ability to accurately model warm-dense matter may enable better control of inertial fusion experiments, and lead to better understanding of interiors of planets and stars. Additionally, in extreme astrophysical environments such as pulsar magnetosphere, strong magnetic fields quantize electron perpendicular momentum and strong electric fields accelerate electron-positron pairs to relativistic energy. Understanding processes in pair plasmas is important for using exotic astrophysical objects as probes for interstellar medium and to test gravitational physics. Finally, relativistic quantum processes can be studied in laboratory during laser-target interactions, where high-energy events like electron-positron pair productions occur in a plasma environment. When scales of collective plasma effects and relativistic quantum effects overlap, field theories provide a unifying framework, which is important when developing novel particle and radiation sources. Our research develops field theories into plasma models and explores overlooked aspects of field theories.
Lattice-gauge model is used to simulate laser-plasma interactions. An intense short-pulse laser impinges on a dense plasma slab and accelerates electrons in the plasma. In the relativistic regime, where the normalized laser amplitude is greater than 1, the simulation recovers the well-known physics of wakefield acceleration. Moreover, in the relativistic-quantum regime, where the amplitude is larger than the ratio of electron rest energy over the laser photon energy, the same model self-consistently captures additional effects such as electron-positron pair production, where cross sections are dressed by dynamical responses. []