Relaxation and decoherence of qubits encoded in collective states of engineered magnetic structures

Abstract

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.

arXiv comment13 pages, 8 figures

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Cited by in corpus (5)

• Enhanced quantum coherence in exchange coupled spins via singlet-triplet transitions
• Harnessing the Quantum Behavior of Spins on Surfaces
• The Lipkin-Meshkov-Glick model with Markovian dissipation -- A description of a collective spin on a metallic surface
• Long spin relaxation times in a transition metal atom in direct contact to a metal substrate
• Spin transfer torque induced paramagnetic resonance