Jellybean quantum dots in silicon for qubit coupling and on-chip quantum chemistry

Abstract

The small size and excellent integrability of silicon metal-oxide-semiconductor (SiMOS) quantum dot spin qubits make them an attractive system for mass-manufacturable, scaled-up quantum processors. Furthermore, classical control electronics can be integrated on-chip, in-between the qubits, if an architecture with sparse arrays of qubits is chosen. In such an architecture qubits are either transported across the chip via shuttling, or coupled via mediating quantum systems over short-to-intermediate distances. This paper investigates the charge and spin characteristics of an elongated quantum dot -- a so-called jellybean quantum dot -- for the prospects of acting as a qubit-qubit coupler. Charge transport, charge sensing and magneto-spectroscopy measurements are performed on a SiMOS quantum dot device at mK temperature, and compared to Hartree-Fock multi-electron simulations. At low electron occupancies where disorder effects and strong electron-electron interaction dominate over the electrostatic confinement potential, the data reveals the formation of three coupled dots, akin to a tunable, artificial molecule. One dot is formed centrally under the gate and two are formed at the edges. At high electron occupancies, these dots merge into one large dot with well-defined spin states, verifying that jellybean dots have the potential to be used as qubit couplers in future quantum computing architectures.

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Cited by in corpus (11)

• Schrödinger cat states of a nuclear spin qudit in silicon
• Strategies for enhancing spin-shuttling fidelities in Si/SiGe quantum wells with random-alloy disorder
• Tomography of entangling two-qubit logic operations in exchange-coupled donor electron spin qubits
• Scalable entanglement of nuclear spins mediated by electron exchange
• Quantum Kernel Learning for Small Dataset Modeling in Semiconductor Fabrication: Application to Ohmic Contact
• An elongated quantum dot as a distributed charge sensor
• Electronic Wigner-Molecule Polymeric Chains in Elongated Silicon Quantum Dots and Finite-Length Quantum Wires
• Resonator-mediated quantum gate between distant charge qubits
• Interplay of Zeeman Splitting and Tunnel Coupling in Coherent Spin Qubit Shuttling
• True decoherence-free-subspace derived from a semiconductor double quantum dot Heisenberg spin-trimer
• Electronic Correlations in Multielectron Silicon Quantum Dots