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arXiv · 2101.11650

Broad-band spectroscopy of a vanadyl porphyrin: a model electronuclear spin qudit

I. Gimeno·A. Urtizberea·J. Román-Roche·D. Zueco·A. Camón·P. J. Alonso·O. Roubeau·F. Luis
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Abstract

We explore how to encode more than a qubit in vanadyl porphyrin molecules hosting a electronic spin 1/2 coupled to a nuclear spin 7/2. The spin Hamiltonian and its parameters, as well as the spin dynamics, have been determined via a combination of electron paramagnetic resonance, heat capacity, magnetization and on-chip magnetic spectroscopy experiments performed on single crystals. We find low temperature spin coherence times of micro-seconds and spin relaxation times longer than a second. For sufficiently strong magnetic fields (B larger than 0.1 T, corresponding to resonance frequencies of 9 to 10 GHz) these properties make vanadyl porphyrin molecules suitable qubit realizations. The presence of multiple equispaced nuclear spin levels then merely provides 8 alternatives to define the 0 and 1 basis states. For lower magnetic fields (below 0.1 T), and lower frequencies (smaller than 2 GHz), we find spectroscopic signatures of a sizeable electronuclear entanglement. This effect generates a larger set of allowed transitions between different electronuclear spin states and removes their degeneracies. Under these conditions, we show that each molecule fulfills the conditions to act as a universal 4-qubit processor or, equivalently, as a d = 16 qudit. These findings widen the catalogue of chemically designed systems able to implement non-trivial quantum functionalities, such as quantum simulations and, especially, quantum error correction at the molecular level.

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BibTeXRIS

I. Gimeno, A. Urtizberea, J. Román-Roche, D. Zueco, A. Camón, P. J. Alonso, O. Roubeau, F. Luis. 2021-01-27. Broad-band spectroscopy of a vanadyl porphyrin: a model electronuclear spin qudit. https://arxiv.org/abs/2101.11650

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