Decoherence in a quantum neural network

In this study, we propose a spin-star model for spin-(1/2) particles in order to examine the coherence dynamics of a quantum neural network (QNN) unit. Since quantum computing paradigm promises advantages over their classical counterparts, quantum versions of neural networks can be examined in this context. We focus on quantum coherence as a natural resource for quantum computing and investigate the central spin coherence of a spin star model in the time domain in a dissipative environment. More particularly, we investigate the extent to which the central spin coherence time would be prolonged under specific parameters and spin-coupling Hamiltonians in a Markov environment. We find that Heisenberg XX-type couplings are more favourable for spin coherence time and the increase on the number of ambient spins extend the coherence time only in this coupling scheme. We also show that Ising-type spin coupling is not desirable since it rapidly diminishes the coherence time in a dissipative environment.