In this letter we present an experimental realization of the quantum mechanics textbook example of two interacting electronic quantum states that hybridize forming a molecular state. In our particular realization, the quantum states themselves are fabricated as quantum dots in a molecule, a carbon nanotube. For sufficient quantum-mechanical interaction (tunnel coupling) between the two quantum states, the molecular wavefunction is a superposition of the two isolated (dot) wavefunctions. As a result, the electron becomes delocalized and a covalent bond forms. In this work, we show that electrical transport can be used as a sensitive probe to measure the relative weight of the two components in the superposition state as a function of the gate-voltages. For the field of carbon nanotube double quantum dots, the findings represent an additional step towards the engineering of quantum states.
@article{arxiv.0705.3962,
title = {Mapping electron delocalization by charge transport spectroscopy in an artificial molecule},
author = {M. R. Graeber and M. Weiss and D. Keller and S. Oberholzer and C. Schoenenberger},
journal= {arXiv preprint arXiv:0705.3962},
year = {2009}
}