Screw-dislocation-engineered quantum dot: geometry-tunable nonlinear optics, orbital qubit addressability, and torsion metrology

• URL: http://arxiv.org/abs/2511.13920v1
• Date: Mon, 17 Nov 2025 21:16:35 GMT
• Title: Screw-dislocation-engineered quantum dot: geometry-tunable nonlinear optics, orbital qubit addressability, and torsion metrology
• Authors: Edilberto O. Silva,
• Abstract summary: We study a single electron confined in a uniform-torsion medium, in a perpendicular magnetic field, and in the presence of an Aharonov--Bohm flux.<n>We find: (i) a torsion-controlled optical transition whose energy blue-shifts from $sim 6.8$ to $sim 15.5$meV and whose saturation intensity varies by an order of magnitude, enabling geometry-programmable optical switching.<n>We also show how torsion provides textitin situ control of emitter--cavity detuning and light-matter coupling in cavity QED, in
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• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: We study a single electron confined in a uniform-torsion medium, a continuum model of a screw dislocation density, in a perpendicular magnetic field, and in the presence of an Aharonov--Bohm flux. Torsion alone produces radial confinement without any \textit{ad hoc} potential, while the Aharonov--Bohm phase breaks the usual $m\leftrightarrow -m$ symmetry. From the exact spectrum and wave functions, we find: (i) a torsion-controlled optical transition whose energy blue-shifts from $\sim 6.8$ to $\sim 15.5$~meV and whose saturation intensity varies by an order of magnitude, enabling geometry-programmable optical switching; (ii) an Aharonov--Bohm-tunable ``angular pseudospin'' formed by the $m=\pm1$ states, with flux-controlled level splitting 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 $\sim 10^{5}~\mathrm{m}^{-1}$. In this context, ``torsion'' refers to the experimentally relevant continuum limit of a uniform density of parallel screw dislocations, i.e., a crystal with finite torsion but vanishing curvature, which can, in practice, be engineered and probed in twisted nanowires and strained semiconductor heterostructures. We also show how torsion provides \textit{in situ} control of emitter--cavity detuning and light--matter coupling in cavity QED, in direct analogy with strain tuning of semiconductor quantum dots in nanocavities, but here arising from a purely geometric/topological parameter.

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