PIRSA:24050099

Shadow Matter

APA

Kaplan, D. (2024). Shadow Matter. Perimeter Institute for Theoretical Physics. https://pirsa.org/24050099

MLA

Kaplan, David. Shadow Matter. Perimeter Institute for Theoretical Physics, May. 27, 2024, https://pirsa.org/24050099

BibTex

          @misc{ scivideos_PIRSA:24050099,
            doi = {10.48660/24050099},
            url = {https://pirsa.org/24050099},
            author = {Kaplan, David},
            keywords = {Particle Physics},
            language = {en},
            title = {Shadow Matter},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2024},
            month = {may},
            note = {PIRSA:24050099 see, \url{https://scivideos.org/pirsa/24050099}}
          }
          

David E. Kaplan Johns Hopkins University - Department of Physics & Astronomy

Talk numberPIRSA:24050099
Source RepositoryPIRSA
Collection

Abstract

I will argue that there are quantum states of the field theories of general relativity and electromagnetism that we typically ignore, but have interesting phenomenological effects. These states amount to relaxing the constraint equations known as the Hamiltonian and momentum constraints in GR and Gauss’ law in EM. Turning off the Hamiltonian constraint sources non-dynamical parts of the metric which mimic a pressure-less dust, and thus these effects may be the explanation as to why we have inferred the existence of dark matter, both locally and cosmologically. Turning off the momentum constraints add additional velocity-dependent source terms to this effective dust, but these effects are not conserved and redshift quickly outside the horizon. Turning off the Gauss’ law constraint mimics a charge density that does not respond to electric forces, but follows geodesics, thus adding a charged component to the dust. The effects in electromagnetism may have interesting impacts on BBN, the baryon-photon fluid during and after recombination, galactic dynamics, and cosmic rays. If this new structure in the gravitational and electric fields explain dark matter, it forbids an early period of inflation and therefore requires a different explanation for density perturbations.