Periodic boundary conditions (PBCs) are a set of boundary conditions which are often chosen for approximating a large (infinite) system by using a small part called a unit cell. PBCs are often used in computer simulations and mathematical models. The topology of two-dimensional PBC is equal to that of a world map of some video games; the geometry of the unit cell satisfies perfect two-dimensional tiling, and when an object passes through one side of the unit cell, it re-appears on the opposite side with the same velocity.
Periodic boundary conditions (PBCs) are a group of boundary conditions frequently utilized to approximate an infinite system by employing a small section known as a unit cell. PBCs are commonly employed in computer simulations and mathematical models. The topology of two-dimensional PBC is equivalent to that found on the map of some video games; the geometry of the unit cell ensures perfect two-dimensional tiling, and when an object crosses one side of the unit cell, it re-enters from the opposite side with identical velocity.