Screw‐Dislocation‐Engineered Quantum Dot: Geometry‐Tunable Nonlinear Optics, Orbital Qubit Addressability, and Torsion Metrology

ABSTRACT We study a single electron confined in a uniform‐torsion medium, the experimentally relevant continuum limit of a uniform density of parallel screw dislocations (finite torsion and vanishing curvature), subject to a perpendicular magnetic field and an Aharonov–Bohm (AB) flux. Torsion alone produces radial confinement without any ad hoc potential, while the AB phase breaks the usual symmetry. Using exact eigenvalues and wave functions, we predict: (i) a torsion‐controlled optical transition that blueshifts from to meV and whose saturation intensity increases from to MW/, enabling geometry‐programmable optical switching; (ii) an AB‐tunable “angular pseudospin” formed by the states, with flux‐controlled level splitting in the –15 meV range and asymmetric oscillator strengths that allow selective optical addressability; and (iii) an approximately linear torsion dependence of the transition energy that enables nanoscale torsion metrology with an estimated resolution of (for ). We also show that torsion provides in situ control of emitter–cavity detuning and light–matter coupling in cavity QED, analogous to strain tuning but driven by a geometric/topological parameter. Each effect is explicitly linked to measurable optical observables (line position, linewidth‐limited resolvability, and oscillator‐strength contrast).