We present a divide-and-conquer approach to deterministically prepare Dicke states |Dnk (i.e., equal-weight superpositions of all n -qubit states with Hamming weight k ) on quantum computers. In an experimental evaluation for up to n=6 qubits on IBM Quantum Sydney and Montreal devices, we achieve significantly higher state fidelity compared to previous results. The fidelity gains are achieved through several techniques: our circuits first “divide” the Hamming weight between blocks of n/2 qubits, and then “conquer” those blocks with improved versions of Dicke state unitaries (Bärtschi et al. FCT’2019). Due to the sparse connectivity on IBM’s heavy-hex-architectures, these circuits are implemented for linear nearest neighbor topologies. Further gains in (estimating) the state fidelity are due to our use of measurement error mitigation and hardware progress.

For more about this article see link below.
For the open access PDF link of this article please click here.