Phase Nexter Operator and Coulomb Barrier Circumvention in Low-Temperature Nuclear Fusion

One of the fundamental challenges of nuclear fusion is the Coulomb barrier between positively charged nuclei. In conventional thermonuclear models, extremely high temperatures are required to provide sufficient kinetic energy for nuclei to overcome electrostatic repulsion. In this work we propose a novel operator-based framework capable of modifying the phase accessibility of nuclear interaction states, inspired by recent developments in dynamic operator formalisms for state-dependent physical evolution. We introduce the \textit{Phase Nexter operator} ($\nexter$), defined as a dynamic transition operator acting in phase-energy configuration space. Unlike conventional approaches that increase particle kinetic energy, this operator enables transitions between metastable interaction phases, effectively bypassing forbidden or highly suppressed energy regions. We demonstrate that this operator belongs to a broader class of four dynamic operators (fluctuating equivalence, cyclic equivalence, phase nextering, and phase reversal) that naturally describe threshold-sensitive, discontinuous physical processes. Within this framework, the Coulomb barrier is interpreted as a restricted phase region rather than a purely energetic obstacle. We derive the operator formalism within an extended Hamiltonian framework and demonstrate how the Phase Nexter operator modifies the effective tunneling probability between nuclear states through a non-adiabatic phase transition mechanism. We further propose experimentally testable triggering mechanisms based on terahertz resonance modulation and quantum coherent platforms, including a quantitative analysis of the coupling parameters required to achieve observable transition probabilities.