2017/02/28 by Varad R. Pande, Gaurav Bhole, Deepak Khurana +1
Computer Science · Mathematics · Physics and Astronomy · #Astrophysics #Combinatorics #Computer network #Computer science #Mathematics #Network topology #Parallel Computing and Optimization Techniques #Physics #Quantum #Quantum Computing Algorithms and Architecture #Quantum and electron transport phenomena #Quantum mechanics #Star (game theory) #Star network #Topology (electrical circuits) #quant-ph
paper · pdf · doi:10.1103/physreva.96.012330
published as Phys. Rev. A 96, 012330 (2017) · 9 pages, 10 figures; close to published version
openalex publication_date 2017/07/25 · arxiv created 2017/07/30 · arxiv updated 2017/08/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Cooling the qubit into a pure initial state is crucial for realizing fault-tolerant quantum information processing. Here we envisage a star-topology arrangement of reset and computation qubits for this purpose. The reset qubits cool or purify the computation qubit by transferring its entropy to a heat bath with the help of a heat-bath algorithmic cooling procedure. By combining standard NMR methods with powerful quantum control techniques, we cool central qubits of two large star-topology systems, with 13 and 37 spins, respectively. We obtain polarization enhancements by a factor of over 24, and an associated reduction in the spin temperature from 298 K down to 12 K. Exploiting the enhanced polarization of computation qubit, we prepare combination coherences of orders up to 15. By benchmarking the decay of these coherences we investigate the underlying noise process. Further, we also cool a pair of computation qubits and subsequently prepare them in an effective pure state.