A Note on the Generalization of the GEMS Approach

This paper is a supplement of our earlier work JHEP 0410 (2004) 011[gr-qc/0409107].We map the vector potential of charged black holes into GEMS and find that its effect on the thermal spectrum is the same as that on the black hole side, i.e., it will induce a chemical potential in the thermal spectrum which is the same as that in the charged black holes.We also argue that the generalization of GEMS approach to non-stationary motions is not possible.Comment: Latex file, 10 pages, no figure; v2: minor corrections; v3: revised with title changed, one new section added and references adde

A Robust Quantum Random Access Memory

A "bucket brigade" architecture for a quantum random memory of $N=2^n$ memory cells needs $n(n+5)/2$ times of quantum manipulation on control circuit nodes per memory call. Here we propose a scheme, in which only average $n/2$ times manipulation is required to accomplish a memory call. This scheme may significantly decrease the time spent on a memory call and the average overall error rate per memory call. A physical implementation scheme for storing an arbitrary state in a selected memory cell followed by reading it out is discussed.Comment: 5 pages, 3 figure