Atomic comagnetometers are used in searches for anomalous spin-dependent interactions. Magnetic field gradients are one of the major sources of systematic errors in such experiments. Here we describe a comagnetometer based on the nuclear spins within an ensemble of identical molecules. The dependence of the measured spin-precession frequency ratio on the first-order magnetic field gradient is suppressed by over an order of magnitude compared to a comagnetometer based on overlapping ensembles of different molecules. Our single-species comagnetometer is capable of measuring the hypothetical spin-dependent gravitational energy of nuclei at the $10^{-17}$ eV level, comparable to the most stringent existing constraints. Combined with techniques for enhancing the signal such as parahydrogen-induced polarization, this method of comagnetometry offers the potential to improve constraints on spin-gravity coupling of nucleons by several orders of magnitude.

中文翻译：

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基于相同分子液体的核自旋磁强计

原子电磁仪用于搜索异常的自旋依赖性相互作用。磁场梯度是此类实验中系统误差的主要来源之一。在这里，我们描述了一个基于相同分子整体中核自旋的电磁仪。与基于不同分子的重叠集合的电磁仪相比，测得的自旋旋进频率比对一阶磁场梯度的依赖性被抑制了一个数量级。我们的单物种电磁仪能够在eV为10 ^ {-17} $ eV的水平上测量假想的自旋依赖性核引力，可与现有最严格的约束条件相提并论。结合增强信号的技术，例如对氢诱导的极化，