Kurucz Z, Sørensen M W, Taylor J M, Lukin M D, Fleischhauer M
Fachbereich Physik, University of Kaiserslautern, D-67663 Kaiserslautern, Germany.
Phys Rev Lett. 2009 Jul 3;103(1):010502. doi: 10.1103/PhysRevLett.103.010502. Epub 2009 Jul 2.
We present a mechanism to protect quantum information stored in an ensemble of nuclear spins in a semiconductor quantum dot. When the dot is charged the nuclei interact with the spin of the excess electron through the hyperfine coupling. If this coupling is made off-resonant, it leads to an energy gap between the collective storage states and all other states. We show that the energy gap protects the quantum memory from local spin-flip and spin-dephasing noise. Effects of nonperfect initial spin polarization and inhomogeneous hyperfine coupling are discussed.
我们提出了一种保护存储在半导体量子点中核自旋系综里的量子信息的机制。当量子点带电时，原子核通过超精细耦合与多余电子的自旋相互作用。如果使这种耦合失谐，就会在集体存储态与所有其他态之间产生一个能隙。我们表明，这个能隙能保护量子存储器免受局部自旋翻转和自旋退相噪声的影响。文中还讨论了非完美初始自旋极化和不均匀超精细耦合的影响。
