Profile
Eleni-Alexandra Kontou
Lecturer in theoretical physics, King’s College London
Kontou studies energy conditions and quantum fields in curved spacetime. Her review with Ko Sanders distinguishes pointwise conditions from averaged conditions and quantum energy inequalities. Her work with Ken Olum derives weak-curvature corrections to a scalar-field bound; related singularity results depend on explicitly stated energy assumptions.
Affiliations
- King’s College London, Department of Mathematics
Channels
Bibliography
A bibliography listing does not establish authorship. Credits appear under attribution.
Published bibliography entries: 3. Showing 1–3 of 3.
Listed work
Paper · 2020
Energy conditions in general relativity and quantum field theory
- Eleni-Alexandra Kontou(Author)
- Ko Sanders(Author)
Eleni-Alexandra Kontou and Ko Sanders review the status of energy conditions in general relativity and quantum field theory, with history, technical results, applications and some new derivations. Pointwise energy conditions began as reasonable limits on matter and became assumptions in proofs of singularity theorems and of the non-existence of wormholes and similar exotic phenomena. Yet quantum fields, and even some simple classical fields, systematically violate every pointwise energy condition. Weaker statements, quantum energy inequalities and averaged energy conditions, hold more widely and may still prove some earlier results. One of them, the achronal averaged null energy condition, is expected to hold universally for gravitating matter, even in semiclassical or quantum gravity.
Listed work
Paper · 2015
Quantum inequality in spacetimes with small curvature
- Eleni-Alexandra Kontou(Author)
- Ken D. Olum(Author)
Eleni-Alexandra Kontou and Ken Olum work on quantum inequalities, bounds on how negative the time-averaged energy density of a quantum field can be. Most were proved in flat spacetime, yet curved-spacetime versions are what decide whether exotic phenomena such as closed timelike curves can exist. Starting from a general inequality by Fewster and Smith, they derive a bound for a minimally coupled scalar field along a geodesic in weakly curved spacetime, to first order in the Ricci tensor. Because only the Ricci tensor appears, paths that meet no matter or energy get no first-order corrections to the flat-space bounds.
Listed work
Paper · 2022
The Return of the Singularities: Applications of the Smeared Null Energy Condition
- Ben Freivogel(Author)
- Eleni-Alexandra Kontou(Author)
- Dimitrios Krommydas(Author)
Freivogel, Kontou and Krommydas note that the classic singularity theorems of general relativity rest on energy conditions that semiclassical gravity can violate. They motivate the smeared null energy condition, a bound on the weighted average of null energy along a finite stretch of a null geodesic. Its field theory version addresses the Fewster-Roman counterexample and reduces to the averaged null energy condition over long segments. Using it as an assumption, they prove a singularity theorem that extends Penrose's theorem to semiclassical gravity. Applied to evaporating black holes and the Maldacena-Milekhin-Popov traversable wormhole, the bound is not saturated by the wormhole in four dimensions, though a reduced two-dimensional version is.