Department of Physics, University of California at San Diego, La Jolla, CA, 92093-0319, USA.
Materials Department, University of California at Santa Barbara, Santa Barbara, CA, 93106-5050, USA.
Nat Commun. 2018 Jun 4;9(1):2158. doi: 10.1038/s41467-018-04667-x.
The Pancharatnam-Berry phase is a geometric phase acquired over a cycle of parameters in the Hamiltonian governing the evolution of the system. Here, we report on the observation of the Pancharatnam-Berry phase in a condensate of indirect excitons (IXs) in a GaAs-coupled quantum well structure. The Pancharatnam-Berry phase is directly measured by detecting phase shifts of interference fringes in IX interference patterns. Correlations are found between the phase shifts, polarization pattern of IX emission, and onset of IX spontaneous coherence. The evolving Pancharatnam-Berry phase is acquired due to coherent spin precession in IX condensate and is observed with no decay over lengths exceeding 10 μm indicating long-range coherent spin transport.
潘那查拉特南-贝里（Pancharatnam-Berry）相是在系统演化的哈密顿量所控制的参数周期中获得的几何相位。在这里，我们报告了在 GaAs 耦合量子阱结构中的间接激子（IXs）凝聚体中观察到的潘那查拉特南-贝里（Pancharatnam-Berry）相。通过检测 IX 干涉图案中的干涉条纹的相移，直接测量了潘那查拉特南-贝里（Pancharatnam-Berry）相。相移、IX 发射的偏振图案和 IX 自发相干的出现之间存在相关性。由于 IX 凝聚体中的相干自旋进动，获得了演化的潘那查拉特南-贝里（Pancharatnam-Berry）相，并观察到在超过 10μm 的长度上没有衰减，表明了长程相干自旋输运。
