arXiv subjects

Cooper Selco

Publications and source records attributed to Cooper Selco.

4 recordsLinked to original sources

arXiv2024

Cryogenic field-cycling instrument for optical NMR hyperpolarization studies

Optical dynamic nuclear polarization (DNP) offers an attractive approach to enhancing the sensitivity of nuclear magnetic resonance (NMR) spectroscopy. Efficient, optically-generated electron polarization can be leveraged to operate across a broad range of temperatures and magnetic fields, making it particularly appealing for applications requiring high DNP efficiency or spatial resolution. While a large class of systems hold promise for optical DNP, many candidates display both variable electron polarizability and electron and nuclear T1 relaxation times as functions of magnetic field and temperature. This necessitates tools capable of studying DNP under diverse experimental conditions. To address this, we introduce a cryogenic field cycling instrument that facilitates optical DNP studies across a wide range of magnetic fields (10mT to 9.4T) and temperatures (10K to 300K). Continuous cryogen replenishment enables sustained, long-term operation. Additionally, the system supports the ability to manipulate and probe hyperpolarized nuclear spins via pulse sequences involving millions of RF pulses. We describe innovations in the device design and demonstrate its operation on a model system of 13C nuclear spins in diamond polarized through optically pumped nitrogen vacancy (NV) centers. We anticipate the use of the instrument for a broad range of optical DNP systems and studies.

quant-ph↗

arXiv2024

Anomalously extended Floquet prethermal lifetimes and applications to long-time quantum sensing

Floquet prethermalization is observed in periodically driven quantum many-body systems where the system avoids heating and maintains a stable, non-equilibrium state, for extended periods. Here we introduce a novel quantum control method using off-resonance and short-angle excitation to significantly extend Floquet prethermal lifetimes. This is demonstrated on randomly positioned, dipolar-coupled, 13C nuclear spins in diamond, but the methodology is broadly applicable. We achieve a lifetime $T_2'~800 s at 100 K while tracking the transition to the prethermal state quasi-continuously. This corresponds to a >533,000-fold extension over the bare spin lifetime without prethermalization, and constitutes a new record both in terms of absolute lifetime as well as the total number of Floquet pulses applied (here exceeding 7 million). Using Laplace inversion, we develop a new form of noise spectroscopy that provides insights into the origin of the lifetime extension. Finally, we demonstrate applications of these extended lifetimes in long-time, reinitialization-free quantum sensing of time-varying magnetic fields continuously for ~10 minutes at room temperature. Our work facilitates new opportunities for stabilizing driven quantum systems through Floquet control, and opens novel applications for continuously interrogated, long-time responsive quantum sensors.

quant-ph↗

arXiv2023

Demonstration of NV-detected $^{13}$C NMR at 4.2 T

The nitrogen-vacancy (NV) center in diamond has enabled studies of nanoscale nuclear magnetic resonance (NMR) and electron paramagnetic resonance with high sensitivity in small sample volumes. Most NV-detected NMR (NV-NMR) experiments are performed at low magnetic fields. While low fields are useful in many applications, high-field NV-NMR with fine spectral resolution, high signal sensitivity, and the capability to observe a wider range of nuclei is advantageous for surface detection, microfluidic, and condensed matter studies aimed at probing micro- and nanoscale features. However, only a handful of experiments above 1 T were reported. Herein, we report $^{13}$C NV-NMR spectroscopy at 4.2 T, where the NV Larmor frequency is 115 GHz. Using an electron-nuclear double resonance technique, we successfully detect NV-NMR of two diamond samples. The analysis of the NMR linewidth based on the dipolar broadening theory of Van Vleck shows that the observed linewidths from sample 1 are consistent with the intrinsic NMR linewidth of the sample. For sample 2 we find a narrower linewidth of 44 ppm. This work paves the way for new applications of nanoscale NV-NMR.

cond-mat.mes-hall↗

arXiv2021

Electron-electron double resonance detected NMR spectroscopy using ensemble NV centers at 230 GHz and 8.3 Tesla

The nitrogen-vacancy (NV) center has enabled widespread study of nanoscale nuclear magnetic resonance (NMR) spectroscopy at low magnetic fields. NMR spectroscopy at high magnetic fields significantly improves the technique's spectral resolution, enabling clear identification of closely related chemical species. However, NV-detected NMR is typically performed using AC sensing through electron spin echo envelope modulation (ESEEM), a hyperfine spectroscopic technique that is not feasible at high magnetic fields. Within this paper, we have explored an NV-detected NMR technique for applications of high field NMR. We have demonstrated optically detected magnetic resonance (ODMR) with the NV Larmor frequency of 230 GHz at 8.3 Tesla, corresponding to a proton NMR frequency of 350 MHz. We also demonstrated the first measurement of electron-electron double resonance detected NMR (EDNMR) using the NV center and successfully detected $^{13}C$ nuclear bath spins. The described technique is limited by the longitudinal relaxation time ($T_1$), not the transverse relaxation time ($T_2$). Future applications of the method to perform nanoscale NMR of external spins at 8.3 T and even higher magnetic fields are also discussed.

cond-mat.mes-hall↗