Hyper-Threading Technology makes a single physical processor appear as two logical processors; the physical execution resources are shared and the architecture state is duplicated for the two logical processors.
So, this means that there are two sets of basic registers such as Next Instruction Pointer, processor registers like AX, BX, CX etc physically embedded in the micro-processor chip,
OR they(arch. state) are made to look two sets by some low level duplication by software/OS.