Feeling the texture of vacuum; Laser acceleration toward PeV

Tajima, Toshiki*; Kando, Masaki; Teshima, Masahiro*

We discuss parameters for laser, plasma, and accelerator technologies that are defined for accelerated electron energies reaching as high as PeV. Although the ambition of luminosity is not pursued, such energies by themselves may allow us to begin to feel and study the physics of the "texture of vacuum". This is an example of fundamental physics exploration without the need of luminosity paradigm. By converting accelerated electrons to photons, and let them propagate through vacuum over a sufficient distance, these extremely high energy photons experience smallest vacuum structures and fluctuations. If we can measure the arrival time differential and thus the photon speed as a function of different energies such as 0.1 PeV vs 1 PeV, we can collect valuable data if and how photons still obeys the premise of relativity or the vacuum texture begins to alter such fundamentals.