Experimental determination of configurational states present in conducting granular heap of disks
We propose an experimental determination of configurational states present in a heap of conducting disks (Philippine five-peso coin, diameter d ≈ 27 mm) determined from the system's net resistance. The experimental setup consists of two conducting vertical bounding walls (height h ≈ 28.5 cm) and a nonconducting bottom floor (width w ≈ 40 cm) to support the heap that forms by dropping the disks one at a time and allowing it to rest on the previously existing heap. Resistance reading over different number of disks N in the heap shows a transition at about N = 50 for the given relative dimensions of the system. The resulting probability density estimate for the resistance values at N = 50 shows the prospect of multiple resistance values as an indication of configurational states of the heap.
We discuss the viability of the approach showing the qualitative similarity of the configurational states of the granular heaps including the possible degeneracy involved.