GAUGE-THEORY FOR A DOPED ANTIFERROMAGNET IN A ROTATING REFERENCE-FRAME

We study the consequences of hole-doping in a two-dimensional spin-1/2 quantum antiferromagnet. The analysis of a U(1) gauge theory that des cribes the system in a rotating reference-frame, where the spin-quanti zation axis of the fermions follow the local order-parameter of the an tiferromagnet, leads to a quantitative description of the transition f rom a Neel ordered to a quantum disordered (QD) spin-liquid phase. Fur thermore, it is shown that the spontaneously generated gap in the spin -wave excitation spectrum defines a new energy scale, which determines the strength of an attractive long-range interaction between magnetic and fermionic excitations. The possible bound-states are singlet obje cts that correspond to the phenomena of charge-spin separation and pai ring. Therefore, a close connection between these phenomena and the op ening of the spin-gap is revealed.