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Research Core 3

Advanced Quantum Sensing for Geoenvironments

This core will focus on determining the feasibility of quantum sensing achieved through solid state nanoscale devices for specific environmental sensing applications. While ambitious, the projects undertaken have the potential to revolutionize the monitoring of emerging phenomena such as hot spots in soil, and thus present excellent opportunities for trainees to perform cutting-edge fundamental science with environmental relevance.

Quantum Sensing of Subsurface Mass Fluctuations

The applicability of quantum-enhanced gravity sensors for measuring subsurface mass changes due to fluctuations in groundwater levels and/or soil moisture will be tested. While atom-interferometer systems are starting to be utilized for such tasks, solid-state systems promise compact, easy-to-use, and cost-effective devices. Scheibner is exploring quantum-enhanced nano-sensors utilizing coupled quantum dots embedded in micromechanical structures. Such non-invasive quantum-enhanced gradiometry would enable high resolution and long-term measurements of subsurface density variability, allowing the detection of changes in groundwater resource levels and changes in soil composition. During the course of the project, while Scheibner, Ghosh, and Strubbe will develop the 2D material-based quantum-enhanced nano-enabled sensors, Berhe, Ghezzehei and Harmon will provide crucial expertise in data evaluation and interpretation, in particular by comparison with established monitoring approaches.

Quantum Sensing of Soil Magnetics

Magnetic properties of soils are indicators for soil development, pollution, and even climate change. The magnetic properties of soils predominantly originate from the presence of iron oxides in various forms and amounts. Iron oxides play a significant role in plant development as well as the formation of clay complexes and organic matter. Consequently, soil magnetism can yield insights on soil structure and fertility. The development of compact and highly sensitive quantum-enhanced magnetometers will enable monitoring of such aspects deeper into the ground as well as for each plant on a field. For that purpose, we will take advantage of the fact that spin states in quantum systems are sensitive to magnetic fields to investigate means to functionalize the above quantum sensors for quantum-enhanced magnetometry. While Scheibner, Ghosh, and Strubbe will work on sensor development, Berhe, Ghezzehei and Harmon will bring expertise in soil science for environmental experiment design and data interpretation.

It is crucial to remember that several elegant sensing systems for environmental monitoring have been devised in the laboratory, yet only very few studies have addressed challenges associated with reliable field deployment. These include maintaining calibration, sensitivity, and selectivity under environmentally variable conditions; reducing interferences, biofouling, and spurious measurements in the presence of complex water or soil matrices; improving sensor longevity, portability, and durability; and preventing release of potentially toxic nanomaterials in sensor deployment or disposal. As such, a common theme to all the projects discussed above will involve attempts to address the common problem of advanced sensors that work well in the lab, but are not robust or reliable in the field , through improved packaging, novel methods, and extensive field testing. Several investigators on this proposal have a range of ongoing environmental monitoring programs that will act as platforms to rigorously test a wide range of sensors in natural and engineered environments. We will also leverage ongoing work at the City of Merced Wastewater Treatment Plant and the UC Merced Vernal Pools and Grasslands Reserve as two convenient nearby test sites with various environmental sensing needs.

Graduate Student Members: Bruce Barrios and Alexia Cooper (Cohort 2), Kyle Wright (Cohort 1)