1998/11/09 by Adam D. Helfer, Helfer, Adam D.
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #High Energy Physics - Theory (hep-th) #Quantum Mechanics and Applications #Quantum, superfluid, helium dynamics #gr-qc #hep-th
paper · pdf · doi:10.48550/arxiv.hep-th/9811081
10 pages, latex, uses sprocl, talk given at the Quantum Fields in External Potentials Workshop, Leipzig, 1998
arxiv created 1998/11/09 · openalex publication_date 1998/11/09 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
I review some recent results showing that the physics of negative energy densities, as predicted by relativistic quantum field theories, is more complicated than has generally been appreciated. On the one hand, in external potentials where there is a time--dependence, however slight, the Hamiltonians are unbounded below. On the other, there are limitations of quantum measurement in detecting or utilizing these negative energies.