Relaxation and decoherence of qubits encoded in collective states of engineered magnetic structures. Shakirov, A., M., Rubtsov, A., N., Lichtenstein, A., I., & Ribeiro, P. Physical Review B, 96(9):094410, 9, 2017.
Relaxation and decoherence of qubits encoded in collective states of engineered magnetic structures [pdf]Paper  Relaxation and decoherence of qubits encoded in collective states of engineered magnetic structures [link]Website  abstract   bibtex   
The quantum nature of a microscopic system can only be revealed when it is sufficiently decoupled from surroundings. Interactions with the environment induce relaxation and decoherence that turn the quantum state into a classical mixture. Here, we study the timescales of these processes for a qubit encoded in the collective state of a set of magnetic atoms deposited on a metallic surface. For that, we provide a generalization of the commonly used definitions of $T_1$ and $T_2$ characterizing relaxation and decoherence rates. We calculate these quantities for several atomic structures, including a collective spin, a setup implementing a decoherence-free subspace and two examples of spin chains. Our work contributes to the comprehensive understanding of the relaxation and decoherence processes and shows the advantages of the implementation of a decoherence free subspace in these setups.

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