In quantum field theory, the Casimir effect (or Casimir force) ^{[ 1 ]} is a physical force acting on the macroscopic boundaries of a confined space which arises from the quantum fluctuations of a field. The term Casimir pressure is sometimes used when it is described in units of force per unit area. ^{[ 2 ] [ 3 ]} It is named after the Dutch physicist Hendrik Casimir, who predicted the effect for electromagnetic systems in 1948.