Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/37464
Title: Robust Quantum Storage with Three Atoms
Authors: HAN RUI
Keywords: Quantum information, quantum storage, decoherence-free qubit, optical lattice, Raman transition, Rydberg excitation
Issue Date: 3-Oct-2012
Source: HAN RUI (2012-10-03). Robust Quantum Storage with Three Atoms. ScholarBank@NUS Repository.
Abstract: In this thesis, we present a systematic construction of a reference-frame-free (RFF) qubit in the noiseless subspace for a system of three identical spin-j atoms. The explicit example of three spin-1/2 <sup>6</sup>Li atoms trapped in an optical lattice is studied to demonstrate the robustness of the RFF qubit storage. The resulting coherence time can be many days and the fidelity of 99.99% is maintained for 2~hrs, with conservatively estimated parameters, making RFF qubits of this kind promising candidates for quantum information storage units. A qubit preparation scheme using the Rydberg blockade mechanism is presented, and the scheme is numerically proven to be robust with a modest estimation of about 98% of the preparation fidelity with existing technologies. The excitation of an atom from the ground state to the Rydberg state is done with a stimulated Raman transition, which is a powerful tool for the manipulation of atoms. In the last part of this thesis, a new methodology for studying the three-level Raman transition in a single atom is presented. Solutions more accurate than those relying on the conventional adiabatic elimination method are obtained without increasing the computational complexity by much. This new method can also be applied to the multi-atom Rydberg excitation that is used for the RFF state preparation.
URI: http://scholarbank.nus.edu.sg/handle/10635/37464
Appears in Collections:Ph.D Theses (Open)

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