The foundation of quantum mechanics and quantum information theory might have an important implication to the quantum field theory and quantum gravity. In this talk, I briefly review the recent development of the application of quantum information theory to new physics searches at the LHC. I also discuss the detection of entanglement and Bell’s inequality test at the LHC and future colliders. Finally, "quantum process tomography” at polarised lepton colliders, a way to test the Quantum Mechanics directly, will be presented.