Coherent manipulation of three spin qubits in a GdW30 single-ion magnet
Abstract
Implementing quantum computation with spins faces the challenge of increasing the number of qubits while keeping errors under control. Even the simplest algorithm implies coupling two or more qubits in a controlled manner. However, dipolar interactions are also an important source of decoherence. Here, we explore a way to scale up quantum resources, without introducing additional decoherence, by integrating several electron spin qubits in a single magnetic ion with spin S > ½. This approach is illustrated with a [Gd(H2O)P5W30O110]12- polyoxometalate single-ion magnet. Electron paramagnetic resonance experiments have been performed on molecules diluted in a crystal of the diamagnetic isostructural derivative [Y(H2O)P5W30O110]12-. The seven allowed transitions between the 2S+1=8 spin states have been separately addressed and its spin coherence T2 and spin-lattice relaxation T1 rates measured. Rabi oscillations have been observed for all transitions. The spin states of each Gd3+ ion can then be mapped onto the states of three addressable qubits (or, alternatively, of a d = 8-level molecular ``qudit''), for which the seven allowed transitions form a universal set of operations. Within this scheme, one of the coherent oscillations observed experimentally provides an implementation of a controlled-controlled-NOT (or Toffoli) three-qubit gate. We also propose a way to implement a simple quantum error correction code using this single-ion ''processor''. Our findings open prospects for developing more complex and robust quantum computation schemes based on molecular spin qubits. Funds were provided by the Spanish MINECO (Grants MAT2015-68204-R and Excellence Unit Maria de Maeztu MDM-2015-0538) and the European Union (COST 15128 Molecular Spintronics and QUANTERA SUMO projects).
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- 2019
- Bibcode:
- 2019APS..MARS36002L