Classical and quantum energy conditions

10:30AM, 16 Feb 2026

Eleni Kontou explores energy conditions in classical general relativity and QFT, showing how quantum bounds constrain negative energy.

Energy conditions are central assumptions in classical general relativity, where they place bounds on the stress–energy tensor and underpin key results such as the singularity theorems. Quantum theory complicates this picture: quantum fields admit states with locally negative energy density, violating classical energy conditions. These violations are not arbitrary, however, and are constrained by quantum energy inequalities that limit their size and duration.

In this course, Dr Eleni Kontou reviews the classical energy conditions, their physical motivation, and the ways in which they can fail in realistic settings. She introduces quantum field theory on curved spacetimes and explains how quantum energy inequalities arise from first principles. The course then explores the average null energy condition in detail, examining the restrictions it places on exotic spacetimes and the implications for causality, spacetime structure, and the foundations of gravitational theory.

Event information

This is a four-part lecture series from LonTI Lectures are on Mondays at 10:30 am in the seminar room at the London Institute, on the second floor of the Royal Institution, followed by drinks and snacks onsite. To register and attend, please visit LonTI website.

Classical and quantum energy conditions
Classical and quantum energy conditions
Classical and quantum energy conditions
Classical and quantum energy conditions
Classical and quantum energy conditions
Classical and quantum energy conditions
Classical and quantum energy conditions
Classical and quantum energy conditions
Classical and quantum energy conditions
Classical and quantum energy conditions
Classical and quantum energy conditions
Classical and quantum energy conditions
Classical and quantum energy conditions
Classical and quantum energy conditions
Classical and quantum energy conditions
Classical and quantum energy conditions

Speakers

Eleni-Alexandra Kontou

Dr Eleni-Alexandra Kontou is a lecturer at King’s College London. She holds a PhD from Tufts University. She was a Research Fellow at the University of York then a postdoc in Amsterdam. Her research focuses on energy conditions and quantum inequalities, and their applications.