We would introduce here a further intrinsic quantum property, pin, like a tiny string, borrowed from the Clifford algebra as back word of spin, other than the intrinsic quantum property, spin, in quantum electrodynamics. In the Clifford algebra, it would be found that spinors are essential in describing spin with the general nature of an intrinsic angular momentum and pinors may be essential in describing pin with the general nature of an intrinsic linear momentum of subatomic particles. The physical consequences of spin and pin in quantum electrodynamics may be obtained in the phenomenon of uniform circular motion of a point object, as such, spin and pin, by acting at right angle to each other in any reference frame, being quantized, would represent the observable quantum states such as subatomic particles. It would also be found that a spin is associated together with an intrinsic magnetic moment, which is the permanent attribute to spin at antiparallel relation and a pin may be associated together with an intrinsic electric moment, which is the permanent attribute to pin at antiparallel relation in quantum electrodynamics and particle physics.
The presence of the four intrinsic properties spin, pin, magnetic moment and electric moment of subatomic particles in quantum electrodynamics may thus open a new perspective of quantum mechanics and particle physics, which may support to find out the isolated quantized electric mono-poles, as well as, the isolated quantized magnetic monopoles as free positive and negative electric and magnetic charges carried by specific particles.
