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SUMMARY:GAnG Seminar: Orlando Luongo - Negative refraction and gravitational metamaterials: From optical geometry to dark matter
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Title: Negative refraction and gravitational metamaterials: From optical geometry to dark matter=0D=0A=
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Abstract: In this talk I propose a novel reinterpretation of spacetime as an effective optical medium capable of exhibiting negative refraction. I show that this phenomenon is not a coordinate artifact, but rather a covariant property of energy-momentum flow, arising when phase propagation and energy transport become oppositely directed. I argue that such a regime is forbidden in minimally coupled general relativity and instead requires non-minimal disformal couplings, which induce an intrinsically anisotropic optical geometry. Within this framework, spacetime can support localized, finite-energy configurations that emerge directly from its optical structure. These objects, which I identify as gravitational metamaterials, behave as particle-like excitations whose effective dynamics, in the weak-field limit, naturally reproduces cold dark matter phenomenology. This suggests a new perspective in which dark matter is not a fundamental component but an emergent geometric manifestation with exotic optical properties. To test this paradigm, I discuss how negative refraction modifies gravitational lensing, potentially leading to observable signatures that distinguish these configurations from standard compact objects and their mimickers.
LOCATION:MB503
DTSTART:20260922T140000
DTEND:20260922T153000
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