Santosh Kumar, Deepak Kumar
We consider a network whose nodes are electromagnetic cavities, each coupled
to a single three-level atom. The nodes are connected by optical fibers. Each
atom is addressed by a control laser, which along with the cavity field drives
atomic transitions. The network can be in the form of chain or two and three
dimensional arrays of $N$-cavities connected by $N_B$ fibers. Following the
work on two-cavity system by Pellizzari, we find that under certain conditions,
the system possesses two kinds of dark states. The first kind are $N$ states
corresponding to atomic excitations at each node and these are our logical
states for quantum processing. The second kind are $N_B$ degenerate dark states
on pairs of sites connected by a fibre. By manipulating intensities and phases
of control lasers on the cavities, one can pass adiabatically among these dark
states due to their degeneracy. This network operates as a $N$-level quantum
system in which one can generate computationally useful states by protocols of
external controls. We obtain numerical results for small chains and lattices to
demonstrate some quantum operations like the transport of states across the
array, generation of W-states and Fourier-like states. We also discuss effects
of dissipation and limitations of the model.
View original:
http://arxiv.org/abs/1202.0408
No comments:
Post a Comment