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.

13 pages, 8 figures

References in corpus (7)

• Observation of Majorana Fermions in Ferromagnetic Atomic Chains on a Superconductor
• Modeling heat transport through completely positive maps
• Protection of excited spin states by a superconducting energy gap
• Spin decoherence of magnetic atoms on surfaces
• Excitation of local magnetic moments by tunnelling electrons
• The emergence of classical behavior in magnetic adatoms
• Role of coherence in transport through engineered atomic spin devices

Cited by in corpus (1)

• Harnessing the Quantum Behavior of Spins on Surfaces