Enhanced nuclear fusion in the sub-keV energy regime

TL;DR

This paper demonstrates that nuclear fusion rates at sub-keV energies can be significantly enhanced within metallic solids due to material effects, challenging traditional expectations of exponential suppression at low energies.

Contribution

It provides experimental evidence of materials-driven enhancement of deuterium-deuterium fusion rates in metallic hydrides at energies below 2.5 keV, revealing a new low-energy fusion regime.

Findings

Fusion yields are over 10^18 times higher than theoretical bare-nucleus rates.

Fusion enhancement occurs below 2.5 keV, contrary to exponential suppression.

Materials environment significantly influences low-energy nuclear fusion processes.

Abstract

Nuclear fusion requires overcoming or traversing a repulsive Coulomb barrier of hundreds of kiloelectronvolts, rendering the probability of fusion at sub-keV energies vanishingly small. Yet in condensed matter, the electronic and structural environment of reacting nuclei can profoundly alter fusion rates. Here we demonstrate that deuterium-deuterium fusion within metallic foils exhibits a pronounced enhancement and reaction yield plateau below energies of 2.5 keV- contrary to the expected exponential suppression with decreasing energy. Using a dual-chamber platform that combines electrochemical deuterium loading with ion-beam bombardment, we show that fusion yields in palladium and titanium hydrides are enhanced by over 10^18 compared to theoretical bare-nucleus fusion rates. These results demonstrate that access to low-energy fusion processes can be governed by materials degrees of freedom. This materials-driven fusion regime establishes a reproducible, tunable framework for studying and ultimately engineering nuclear reactions in solids. While the reaction rates reported here are low, these insights into materials-modulated fusion processes offer a potential foundation for understanding how condensed-matter environments could influence future fusion-energy concepts.