Using particle trajectory data obtained from x-ray tomography, we determine two kinds of effective temperatures in a cyclically sheared granular system. The first one is obtained from the fluctuation-dissipation theorem which relates the diffusion and mobility of lighter tracer particles immersed in the system. The second is the Edwards compactivity defined via the packing volume fluctuations. We find robust excellent agreement between these two temperatures, independent of the type of the tracers, cyclic shear amplitudes, and particle surface roughness. We further elucidate that in granular systems the viscous-like drag force is due to the broken symmetry of the local contact geometry.

中文翻译：

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循环剪切颗粒系统中波动耗散和爱德华兹温度的等效性

使用从 X 射线断层扫描获得的粒子轨迹数据，我们确定了循环剪切颗粒系统中的两种有效温度。第一个是从波动耗散定理获得的，该定理涉及浸入系统中的较轻示踪粒子的扩散和迁移率。第二个是通过堆积体积波动定义的 Edwards 紧致性。我们发现这两个温度之间非常一致，与示踪剂的类型、循环剪切幅度和颗粒表面粗糙度无关。我们进一步阐明，在粒状系统中，粘性阻力是由于局部接触几何形状的对称性破坏所致。