极化中子实验中几何相位的新观点

证明Bell不等式违反的极化中子干涉仪的改进

Improvement of the polarized neutron interferometer setup demonstrating violation of a Bell-like inequality

为了用极化中子进行精确测量，需要高效的自旋操纵。我们开发了几种适合于新的复杂装置的中子光学元件，即，直流自旋翻转器和Larmor加速器，大大减少了热扰动和去极化。利用性能的增益证明违反了一个类贝尔不等式的自旋路径纠缠单中子态。所获得的S=2.365（13）的值比先前通过中子干涉测量法测量的值高得多，比上下文隐变量理论预测的S=2的极限高28 $σ$。新的设置在状态准备和分析方面更加灵活，因此可以进行新的、更精确的测量。

用极化中子观测非加性混合态相位

Observation of nonadditive mixed state phases with polarized neutrons

在中子极化测量实验中，自旋本征态之间的混合态相对相位是由测量的强度振荡的最大值和最小值确定的。我们认为演变导致纯粹的几何，纯粹的动力学和相结合。它是实验证明，单独确定的几何和动力学相位的总和是不等于从一个单一的测量获得的相关的总相位，除非系统是在一个纯粹的状态。

Definitive Detection of Orbital Angular Momentum States in Neutrons by Spin-polarized $^3$He

A standard method to detect thermal neutrons is the nuclear interaction $^3$He(n,p)$^3$H. The spin-dependence of this interaction is also the basis of a neutron spin-polarization filter using nuclear polarized $^3$He. We consider the corresponding interaction for neutrons placed in an intrinsic orbital angular momentum (OAM) state. We derive the relative polarization-dependent absorption cross-sections for neutrons in an $L=1$ OAM state. The absorption of those neutrons results in compound states $J^π=0^-$, $1^-$, and $2^-$. Varying the three available polarizations tests that an OAM neutron h…

Electric field imaging using polarized neutrons

We experimentally demonstrate that electrically neutral particles, neutrons, can be used to directly visualize the electrostatic field inside a target volume that can be isolated or occupied. Electric-field images were obtained using a polychromatic, spin-polarized neutron beam with a sensitive polarimetry scheme. This work may enable new diagnostic power of the structure of electric potential, electric polarization, charge distribution, and dielectric constant by imaging spatially dependent electric fields in objects that cannot be accessed by other conventional probes.

First Measurement of Neutron Birefringence in Polarized $^{129}$Xe and $^{131}$Xe Nuclei

We present the first measurements of polarized neutron birefringence in transmission through nuclear-polarized $^{129}$Xe and $^{131}$Xe gas and determine the neutron incoherent scattering lengths $b_i(^{129}Xe)=0.186\pm(0.021)_{stat.}\pm(0.004)_{syst.}\space\text{ fm}$ and $b_i(^{131}Xe)=2.09\pm(0.29)_{stat.}\pm(0.12)_{syst.}\space\text{ fm}$ for the first time. These results determine the essential parameter needed for interpretation of spin-dependent neutron-scattering studies on polarized xenon ensembles, with possible future applications ranging from tests of time-reversal violation to mo…

极化中子干涉仪实验中非对角几何相位的观测

Observation of off-diagonal geometric phase in polarized neutron interferometer experiments

本文用极化中子干涉仪研究了自旋为1/2的系统演化过程中获得的非对角几何相位。最后的计数与偏振分析，使我们能够同时观察两个检测器的非对角和对角几何相位。我们已经定量测量了非周期演化的非对角几何相位，证实了理论预测。我们讨论了我们的实验中的几何相位（对角和非对角）和量子擦除现象的意义。