CAREER: Characterization of quantum dot qubits by scannable mechanical resonator

Non-technical abstract:

In order to speed up the realization of the quantum technology for novel applications such as quantum computing, it is critical to carefully study new types of materials that can be used as quantum bits. This CAREER project pursues experimental techniques to study diverse nanometer-scale materials such as nanoparticles, nanowires and molecules for their potential use in making quantum bits at their individual level.

The research adopts a scanning probe microscopy technique which employs a mechanical resonator to detect the motion of a single electron in these materials. The project lays the foundation of a new way of studying nanomaterials as quantum bits. The research activities are closely integrated with educational activities that include: 1) training graduate and undergraduate students at Texas State University and collaborating universities in applying state­-of-the art scanning probe microscopy based measurement techniques for material characterization and create a network of researchers, and 2) engaging a diverse student body at various levels including middle and high school in nano- and quantum-science through workshops with hands-on activities.

Technical abstract:

This CAREER project aims to investigate how a mechanical resonator can be used to characterize quantum mechanical properties of qubits realized in a double quantum dot such as tunnel coupling, relaxation and coherence, by adopting a mechanical charge sensing technique based on atomic force microscopy. The use of scannable probes makes it possible to characterize double quantum dots by positioning the probe above the target quantum dot, without integrating a resonator or sensing electrodes nearby.

The outcome of this project will broaden the fundamental understanding of the coupling between mechanical resonators and qubits based on double quantum dots and will open the path for the study of a broad range of nanomaterials – nanoparticle complexes, nanowires, self­-assembled quantum dots and engineered molecules– that have not been investigated as qubits. These qubits could operate at much higher temperatures due to their higher confinement energy, enabling wider spread use of quantum technology.

The project will support the training of graduate and undergraduate students in advanced cryogenic scanning probe microscopy instrumentation and nanofabrication.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.