Quantum Sensing with Solid-State Spin Qubits

We are pursuing a broad program of basic physics and quantum sensing applications with solid-state spin qubits — e.g., using the nitrogen vacancy (NV) color center in diamond. The NV center is a quantum defect with both electronic and nuclear spin, exhibiting long spin coherence times under ambient conditions. The NV is a single photon emitter, and its spin state can be optically prepared and read-out with good fidelity. NVs can be created within diamond at both high and low density, as well as within a few nanometers of the diamond surface. Diamond is a robust, biocompatible material that can be fabricated into a wide variety of shapes, from nanoscale structures to macroscopic crystals. NV-diamond is now a leading modality for sensing of electromagnetic fields and temperature with high spatial and spectral resolution.

NV-Diamond Magnetometry

We and our collaborators pioneered the use of NV-diamond for precision magnetic sensing and imaging with high spatial and spectral resolution. We continue to advance the performance of NV-diamond magnetometry, and pursue diverse applications across the physical and life sciences. Some examples in condensed matter physics and geoscience are illustrated on this page. Other example applications are in bioimaging and NMR.
Lower left: Quantum diamond microscope (QDM) used for studies of paleomagnetism in early Earth rocks and meteorites. Upper left: QDM map of magnetic fields in a rock from western Australia; zircon is >4 Gyrs old and may provide information on the early Earth's geodynamo. Upper right: NV-diamond magnetic field map of the chiral structure of a skyrmion found in a magnetic multi-layer. Lower right: NV-diamond measurements of the spin chemical potential of magnons in a magnetic insulator.

Driven Quantum Matter

The control of complex quantum systems and the development of next-generation quantum devices forms one of the grand technological challenges of the 21st century. Surprisingly, the stabilization of such quantum systems can rise out of their own complexity, originating from exotic non-equilibrium phases or intrinsic disorder in the system. We are exploring driven, non-equilibrium quantum phases with the goal of predicting, optimizing, discovering, and applying new types of quantum matter.

We combined two complementary quantum control techniques -- double quantum (DQ) coherence and spin bath driving (P1) -- to extend the dephasing time (T2*) of an NV ensemble by a factor of 16x (left), thereby improving the broadband (DC) magnetic field sensitivity by a factor of 8x (right). This result corresponds to the longest T2* ever measured for any solid-state electronic spin ensemble at room temperature.

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