The fractional quantum Hall effect (FQHE) is a remarkable phenomenon that occurs in two-dimensional electron systems subjected to strong magnetic fields and low temperatures. In the FQHE, the electrical conductance of the system exhibits plateaus at specific fractional values of the ratio between the Hall resistance and the resistance. These plateaus are associated with the formation of quasiparticles known as quasiholes, which behave as particles with fractional electric charges.

Traditionally, the observation of the FQHE has required the presence of physical edges in the two-dimensional electron system. These edges are necessary to confine the quasiholes and prevent them from recombining with electrons, which would destroy the fractional charge. However, recent experiments have demonstrated that the FQHE can also be realized in systems without any physical edges.

In these experiments, the quasiholes are confined by a periodic potential created by an array of metallic gates on the surface of the two-dimensional electron system. The gates create a pattern of potential hills and valleys that trap the quasiholes and prevent them from moving freely. This confinement mechanism allows the FQHE to be observed even in the absence of physical edges.

The realization of the FQHE without edges is a significant breakthrough that opens up new possibilities for studying this fascinating quantum phenomenon. By eliminating the need for physical edges, researchers can now investigate the FQHE in systems with different geometries and boundary conditions. This will enable a deeper understanding of the underlying physics of the FQHE and may lead to the discovery of new and exotic quantum states.