## 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.

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.

### References

**Sensitivity Optimization for NV-Diamond Magnetometry**. John F. Barry, Jennifer M. Schloss, Erik Bauch, Matthew J. Turner, Connor A. Hart, Linh M. Pham, and Ronald L. Walsworth. arXiv:1903.08176 (2019).**Geometric phase magnetometry using a solid-state spin**. K. Arai, J. Lee, C. Belthangady, D. R. Glenn, H. Zhang, and R. L. Walsworth. Nature Communications**9**, 4996 (2018).**A microwave-assisted spectroscopy technique for determining charge state in nitrogen-vacancy ensembles in diamond**. D. P. L. Aude Craik, P. Kehayias, A. S. Greenspon, X. Zhang, M. J. Turner, J. M. Schloss, E. Bauch, C. A. Hart, E. L. Hu, R. L. Walsworth. arXiv:1811.01972 (2018).**Spin-torque oscillation in a magnetic insulator probed by a single-spin sensor**. H. Zhang, M.J.H. Ku, F. Casola, C.H. Du, T. van der Sar, M.C. Onbasli, C.A. Ross, Y. Tserkovnyak, A. Yacoby, R.L. 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Nature Communications**9**, 2712 (2018).**Supplementary material**for the above article.**Fundamental Precision Bounds for Three-Dimensional Optical Localization Microscopy with Poisson Statistics**. Mikael P. Backlund, Yoav Shechtman, and Ronald L. Walsworth. Phys. Rev. Lett.**121**, 023904 (2018).**Supplementary material**for the above article.**Sensing Coherent Dynamics of Electronic Spin Clusters in Solids**. E. L. Rosenfeld, L. M. Pham, M. D. Lukin, and R. L. Walsworth. Phys. Rev. Lett.**120**, 243604 (2018).**Supplementary material**for the above article.**Secondary magnetic inclusions in detrital zircons from the Jack Hills, Western Australia, and implications for the origin of the geodynamo**. Benjamin P. Weiss, Roger R. Fu, Joshua F. Einsle, David. R. Glenn, Pauli Kehayias, Elizabeth A. Bell, Jeff Gelb, Jefferson F.D.F. Araujo, Eduardo A. Lima, Cauê S. Borlina, Patrick Boehnke, Duncan N. Johnstone, T. Mark Harrison, Richard J. Harrison, and Ronald L. 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Kehayias, and R. L. Walsworth arXiv:1801.03793 (2018).**Probing condensed matter physics with magnetometry based on nitrogen-vacancy centres in diamond**. Francesco Casola, Toeno van der Sar, and Amir Yacoby Nature Review Materials vol 3, 17088 (2018).**Bright nanowire single photon source based on SiV centers in diamond**. L. Marseglia, K. Saha, A. Ajoy, T. Schroder, D. Englund, F. Jelezko, R. L. Walsworth, J. L. Pacheco, D. L. Perry, E. S. Bielejec, and P. Cappellaro Optics Express Vol. 26, Issue 1, pp. 80-89 (2018).**Sensing coherent dynamics of electronic spin clusters in solids**. E. L. Rosenfeld, L. M. Pham, M. D. Lukin, and R. L. Walsworth arXiv:1801.00198 (2017).**Improved quantum sensing with a single solid state spin via spin to charge conversion**. J.-C. Jaskula1, B. J. Shields, E. Bauch, M. D. Lukin, A. S. Trifonov, and R. L. Walsworth. arXiv:1711.02023 (2017).**Diamond-Based Magnetic Imaging with Fourier Optical Processing.**M. P. Backlund, P. Kehayias, and R. L. Walsworth. Phys Rev App 8, 054003 (2017).**Micrometer-scale Magnetic Imaging of Geological Samples using a Quantum Diamond Microscope**. D. R. Glenn, R. R. Fu, P. Kehayias, D. Le Sage, E. A. Lima, B. P. Weiss, and R. L. Walsworth. Geochemistry, Geophysics, Geosystems, 18, doi:10.1002/ 2017GC006946 (2017).**A method for directional detection of dark matter using spectroscopy of crystal defects**. S. Rajendran, N. Zobrist, A. O. Sushkov, R. L. Walsworth, and M. D. Lukin. Phys. Rev. D 96, 035009 (2017).**Selective addressing of solid-state spins at the nanoscale via magnetic resonance frequency encoding**. H. Zhang, K. Arai, C. Belthangady, J.-C. Jaskula, and R. L. Walsworth. NPJ Quantum Information 3:31 (2017).**Supplementary material**for the above article.**Micrometer-scale Magnetic Imaging of Geological Samples using a Quantum Diamond Microscope**. D. R. Glenn, R. R. Fu, P. Kehayias, D. Le Sage, E. A. Lima, B. P. Weiss, and R. L. 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Bauch, S. Arroyo-Camejo, M. D. Lukin, S. W. Hell, A. S. Trifonov, R. L. Walsworth. Optics Express Vol.25, No.10 (2017).**Nanodiamond-enhanced MRI via in situ hyperpolarization**. D. E. J. Waddington, M. Sarracanie, H. Zhang, N. Salameh, D. R. Glenn, E. Rej, T. Gaebel, T. Boele, R. L. Walsworth, D. J. Reilly, and M. S. Rosen. Nature Communications DOI:10.1038/ncomms15118 (2017).**Supplementary material**for the above article.**Efficiency of Cathodoluminescence Emission by Nitrogen-Vacancy Color Centers in Nanodiamonds**. H. Zhang, D. R. Glenn, R. Schalek, J. W. Lichtman, and R. L. Walsworth. Small 2017.1700543 (2017).**Supplementary material**for the above article.**Evaluating the paleomagnetic potential of single zircon crystals using the Bishop Tuff**. R. R. Fu, B. P. Weiss, E. A. Lima, P. Kehayias, J. F. D. F. Araujo, D. R. Glenn, J. Gelb, J. F. Einsle, A. M. Bauer, R. J. Harrison, G. A.H. Ali, R. L. Walsworth. EPSL**458**1-13 (2017).**Control and Local Measurement of the Spin Chemical Potential in a Magnetic Insulator**. C. Du, T, Van der Sar, T. X. Zhou, P. Upadhyaya, F. Casola, H. Zhang, M. C. Onbasli, C. A. Ross, R. L. Walsworth, Y. Tserkovnyak, A. Yacoby. arXiv:1611.07408 (2016).**Optical magnetic detection of single-neuron action potentials using quantum defects in diamond**. J. F. Barry, M. J. Turner, J. M. Schloss, D. R. Glenn, Y. Song, M. D. Lukin, H. Park, and R. L. Walsworth. PNAS Early Edition (2016).**Nanodiamond-enhanced MRI**. D. E. J. Waddington, M. Sarracanie, H. Zhang, N. Salameh, D. R. Glenn, E. Rej, T. Gaebel, T. Boele, R. L. Walsworth, D. J. Reilly, and M. S. Rosen. arXiv:1611.05167v1 (2016).**Imaging the Spin Texture of a Skyrmion Under Ambient Conditions Using an Atomic-Sized Sensor**. Y. Dovzhenko, F. Casola, S. Schlotter,T. X. Zhou, F. B¨uttner, R. L. Walsworth, G. S. D. Beach, and A. Yacoby. arXiv:1611.00673v1 (2016).**Selective addressing of solid-state spins at the nanoscale via magnetic resonance freqeuncy encoding**. H. Zhang, K. Arai, C. Belthangady, J. Jaskula, R. L. Walsworth. arXiv:1610.06630 (2016).**Superresolution optical magnetic imaging and spectroscopy using individual electronic spins in diamond**. J. Jaskula, E. Bauch, S. Arroyo-Camejo, M. D. Lukin, S. W. Hell, A. S. Trifonov, R. L. Walsworth. arXiv:1610.02097 (2016).**Mapping the Microscale Origins of MRI Contrast with Subcellular NV Diamond Magnetometry**. H. C. Davis, P. Ramesh, A. Bhatnagar, A. Lee-Gosselin1, J. F. Barry, D. R. Glenn, R. L. Walsworth, M. G. Shapiro. arXiv:1610.01924 (2016).**Evaluating the paleomagnetic potential of single zircon crystals using the Bishop Tuff**. R. R. Fu, B. P. Weiss, E. A. Lima, P. Kehayias, J. F. D. F. Araujo, D. R. Glenn, J. Gelb, J. F. Einsle, A. M. Bauer, R. J. Harrison, G. A.H. Ali, R. L. Walsworth. arXiv:1605.08479 (2016).**Nuclear magnetic resonance detection and spectroscopy of single proteins using quantum logic**. I. Lovchinsky, A. O. Sushkov, E. Urbach, N. P. de Leon, S. Choi, K. De Greve, R. Evans, R. Gertner,E. Bersin, C. Müller, L. McGuinness, F. Jelezko, R. L. Walsworth, H. Park, M. D. Lukin. Science**351**, 836-840 (2016).**Optical magnetic detection of single-neuron action potentials using quantum defects in diamond**. J. F. Barry, M. J. Turner, J. M. Schloss, D. R. Glenn, Y. Song, M. D. Lukin, H. Park, R. L. Walsworth. arXiv:1602.01056 (2016).**Efficiency of Cathodoluminescence Emission by Nitrogen-Vacancy Color Centers in Nanodiamond**. Huiliang Zhang, David R. Glenn, Richard Schalek, Jeff W. Lichtman, Ronald L. Walsworth. arXiv:1602.00410 (2016).**NMR Technique for Determining the Depth of Shallow Nitrogen-Vacancy Centers in Diamond**. L. M. Pham, S. J. DeVience, F. Casola, I. Lovchinsky, A. O. Sushkov, E. Bersin, J. Lee, E. Urbach, P. Cappellaro, H. 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Toeno van der Sar, Francesco Casola, Ronald Walsworth, Amir Yacoby, Nature Communications, DOI: 10.1038/ncomms8886 (2015).**Supplementary material**for the above article.**Fourier Magnetic Imaging with Nanoscale Resolution and Compressed Sensing Speed-up using Electronic Spins in Diamond**. K. Arai, C. Belthangady, H. Zhang, N. Bar-Gill, S. J. DeVience, P. Cappellaro, A. Yacoby, R. L. Walsworth, Nature Nanotechnology**10**, 859–864 (2015).**Supplementary material**for the above article.**Single-cell magnetic imaging using a quantum diamond microscope**. D. R. Glenn, K. Lee, H. Park, R. Weissleder, A. Yacoby, M. D. Lukin, H. Lee, R. L. Walsworth, C. B. Connolly, Nature Methods**12**, 736–738 (2015).**Supplementary material**for the above article.

**Nanoscale NMR spectroscopy and imaging of multiple nuclear species**. S. J. DeVience, L. M. Pham, I. Lovchinsky, A. O. Sushkov, N. Bar-Gill, C. Belthangady, F. Casola, M. Corbett, H. Zhang, M. D. Lukin, H. Park, A. Yacoby, R. L. Walsworth. Nature Nanotechnology**10**, 129-134 (2015). arxiv:1406.3365.**Supplementary material**for the above article.

**Decoherence imaging of spin ensembles using a scanning single-electron spin in diamond**. L. Luan, M. S. Grinolds, S. Hong, P. Maletinsky, R. L. Walsworth, A. Yacoby. Scientific Reports**5**, 8119 (2015).**Atomic-Scale Nuclear Spin Imaging Using Quantum-Assisted Sensors in Diamond**. A. Ajoy, U. Bissbort, M. D. Lukin, R. L. Walsworth, P. Cappellaro. Physical Review X**5**, 011001 (2015). arxiv:1407.3134.**A Genetic Strategy for Probing the Functional Diversity of Magnetosome Formation**. L. Rahn-Lee, M. E. Byrne, M. Zhang, D. Le Sage, D. R. Glenn, T. Milbourne, R. L. Walsworth, H. Vali, A. Komeili. PLOS Genetics**11**(1), e1004811 (2015).**All-Optical Sensing of a Single-Molecule Electron Spin**. A. O. Sushkov, N. Chisholm, I. Lovchinsky, M. Kubo, P. K. Lo, S. D. Bennett, D. Hunger, A. Akimov, R. L. Walsworth, H. Park, M. D. Lukin. Nano Letters**14**(11), 6443-6448 (2014).**Supplementary material**for the above article.

**Solar nebula magnetic fields recorded in the Semarkona meteorite**. R. R. Fu, B. P. Weiss, E. A. Lima, R. J. Harrison, X.-N. Bai, S. J. Desch, D. S. Ebel, C. Suavet, H. Wang, D. Glenn, D. Le Sage, T. Kasama, R. L. Walsworth, A. T. Kuan. Science**346**, 6213 (2014).**Supplementary material**for the above article.

**Magnetic resonance detection of individual proton spins using quantum reporters**. A. O. Sushkov, I. Lovchinsky, N. Chisholm, R. L. Walsworth, H. Park, and M. D. Lukin. Physical Review Letters**113**, 197601 (2014). arxiv:1410.3750.**Atom-like crystal defects: From quantum computers to biological sensors**. L. Childress, R. Walsworth, and M. Lukin. Physics Today**67**(10), 38 (2014).**Silicon-Vacancy Color Centers in Nanodiamonds: Cathodoluminescence Imaging Markers in the Near Infrared**. H. Zhang, I. Aharonovich, D.R. Glenn, R. Schalek, A.P. Magyar, J.W. Lichtman, E.L. Hu, and R.L. Walsworth. Small (2014). doi: 10.1002/smll.201303582.**Sub-nanometer resolution in three-dimensional magnetic-resonance imaging of individual dark spins**. M.S. Grinolds, M. Warner, K. De Greve, Y. Dovzhenko, L. Thiel, R.L. Walsworth, S. Hong, P. Maletinsky, and A. Yacoby. Nature Nanotechnology**9**, 279 (2014). arxiv:1401.2674.**All-optical sensing of a single-molecule electron spin**. A.O. Sushkov, N. Chisholm, I. Lovchinsky, M. Kubo, P.K. Lo, S.D. Bennett, D. Hunger, A. Akimov, R.L. Walsworth, H. Park, and M.D. Lukin. arxiv:1311.1801.**Limits to resolution of CW STED microscopy**. A.S. Trifonov, J.C. Jaskula, C. Teulon, D.R. Glenn, N. Bar-Gill, and R.L. Walsworth. Advances In Atomic, Molecular, and Optical Physics**62**, 279-302 (2013).**Optical magnetic imaging of living cells**. D. Le Sage, K. Arai, D. R. Glenn, S. J. DeVience, L. M. Pham, L. Rahn-Lee, M. D. Lukin, A. Yacoby, A. Komeili, and R. L. Walsworth. Nature**496**, 486-489 (2013).**Solid-state electronic spin coherence time approaching one second**. N. Bar-Gill, L. M. Pham, A. Jarmola, D. Budker, and R. Walsworth. Nature Communications**4**, 1743 (2013). arxiv:1211.7094.**Dressed-State Resonant Coupling between Bright and Dark Spins in Diamond**. C. Belthangady, N. Bar-Gill, L. M. Pham, K. Arai, D. Le Sage, P. Cappellaro, and R. L. Walsworth. Physical Review Letters**110**, 157601 (2013). arxiv:1211.2749.**Nanoscale magnetic imaging of a single electron spin under ambient conditions**. M. S. Grinolds, S. Hong, P. Maletinsky, L. Luan, M. D. Lukin, R. L. Walsworth, A. Yacoby. Nature Physics**9**, 215 (2013).**Supplementary material**for the above article.

**Optical magnetometry with nitrogen-vacancy centers in diamond**. V.M. Acosta, D. Budker, P.R. Hemmer, J.R. Maze, and R.L. Walsworth, in*Optical Magnetometry*, edited by D. Budker and D. F. Jackson Kimball (Cambridge University Press, Cambridge, UK, 2013), pp. 142-166.**Nanoscale magnetometry with NV centers in diamond**. S. Hong, M. S. Grinolds, L. M. Pham, D. Le Sage, L. Luan, R. L. Walsworth, A. Yacoby. Materials Research Society Bulletin**38**, 155 (2013).**Correlative light and electron microscopy using cathodoluminescence from nanoparticles with distinguishable colours**. D. R. Glenn, H. Zhang, N. Kasthuri, R. Schalek, P. K. Lo, A. S. Trifonov, H. Park, J. W. Lichtman, and R. L. Walsworth. Scientific Reports**2**, 865 (2012). arxiv:1208:1249.**Supplementary material**for the above article.

**Dressed-State Polarization Transfer between Bright & Dark Spins in Diamond**. C. Belthangady, N. Bar-Gill, L. M. Pham, K. Arai, D. Le Sage, P. Cappellaro, and R. L. Walsworth. arxiv:1211.2749.**Enhanced metrology using preferential orientation of nitrogen-vacancy centers in diamond**. L. M. Pham, N. Bar-Gill, D. Le Sage, C. Belthangady, A. Stacey, M. Markham, D. J. Twitchen, M. D. Lukin, and R. L. Walsworth. Physical Review B,**86**, 121202(R) (2012). arxiv:1207.3363.**Supplementary material**for the above article.

**Coherent, mechanical control of a single electronic spin**. S. Hong, M. S. Grinolds, P. Maletinsky, R. L. Walsworth, M. D. Lukin, and A. Yacoby. Nano Letters,**12**, 8, 3920-3924 (2012). arxiv:1202.1823.**Enhanced solid-state multi-spin metrology using dynamical decoupling**. L. M. Pham, N. Bar-Gill, C. Belthangady, D. Le Sage, P. Cappellaro, M. D. Lukin, A. Yacoby, and R. L. Walsworth. Physical Review B,**86**, 045214 (2012). arxiv:1201.5686.**Anti-reflection coating for nitrogen-vacancy optical measurements in diamond**. T. K. Yeung, D. Le Sage, L. M. Pham, P. L. Stanwix, and R. L. Walsworth. Applied Physics Letters,**100**, 251111 (2012).**Suppression of spin-bath dynamics for improved coherence of multi-spin-qubit systems**. N. Bar-Gill, L. M. Pham, C. Belthangady, D. Le Sage, P. Cappellaro, J. R. Maze, M. D. Lukin, A. Yacoby, and R. Walsworth. Nature Communications,**3**, 858 (2012). arxiv:1112.0667.**A robust scanning diamond sensor for nanoscale imaging with single nitrogen-vacancy centres**. P. Maletinsky, S. Hong, M.S. Grinolds, B. Hausmann, M.D. Lukin, R.L. Walsworth, M. Loncar, and A. Yacoby. Nature Nanotechnology,**7**, 320–324 (2012). 10.1038/nnano.2012.50. arXiv:1108.4437.**Efficient photon detection from color centers in a diamond optical waveguide**. D. Le Sage, L. M. Pham, N. Bar-Gill, C. Belthangady, M. D. Lukin, A. Yacoby, and R. L. Walsworth. Physical Review B,**85**, 121202(R) (2012). arxiv:1201.0674.**Supplementary material**for the above article.

**Quantum control of proximal spins using nanoscale magnetic resonance imaging**. M.S. Grinolds, P. Maletinsky, S. Hong, M.D. Lukin, R.L Walsworth, and A. Yacoby. Nature Physics,**7**687 (2011).**Supplementary material**for the above Nature Physics article.

**Magnetic field imaging with nitrogen-vacancy ensembles**. L.M. Pham, D. Le Sage, P.L. Stanwix, T.K. Yeung, D. Glenn, A. Trifonov, P. Cappellaro, P.R. Hemmer, M.D. Lukin, H. Park, A. Yacoby and R.L. Walsworth. New Journal of Physics**13**045021 (2011).**Far-field optical imaging and manipulation of individual spins with nanoscale resolution**. P.C. Maurer, J.R. Maze, P.L. Stanwix, L. Jiang, A.V. Gorshkov, A.A. Zibrov, B. Harke, J.S. Hodges, A.S. Zibrov, D. Twitchen, S.W. Hell, R.L. Walsworth and M.D. Lukin. Nature Physics,**6**912 (2010).**Coherence of Nitrogen-Vacancy Electronic Spin Ensembles in Diamond**. P.L. Stanwix, L.M. Pham, J.R. Maze, D. Le Sage, T.K. Yeung, P. Cappellaro, P.R. Hemmer, A. Yacoby, M.D. Lukin, and R.L. Walsworth, Physical Review B, Rapid Communications,82 201201(R) (2010).**Repetitive Readout of a Single Electronic Spin via Quantum Logic with Nuclear Spin Ancillae**. L. Jiang, J.S. Hodges, J.R. Maze, P. Maurer, J.M. Taylor, D.G. Cory, P.R. Hemmer, R.L. Walsworth, A.Yacoby, A.S. Zibrov, and M.D. Lukin, Science, 326, 267 (2009).**High-sensitivity diamond magnetometer with nanoscale resolution**. J.M. Taylor, P. Cappellaro, L. Childress, L. Jiang, D. Budker, P.R. Hemmer, A. Yacoby, R.L. Walsworth and M.D. Lukin, Nature Physics 4, 810-816 (2008)**Nanoscale magnetic sensing with an individual electronic spin in diamond**. J.R. Maze, P.L. Stanwix, J.S. Hodges, S. Hong, J.M. Taylor, P. Cappellaro, L. Jiang, M.V. Gurudev Dutt, E. Togan, A.S. Zibrov, A. Yacoby, R.L. Walsworth and M.D. Lukin, Nature 455, 644-648 (2008).