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Nayden P. Nedev

Publications and source records attributed to Nayden P. Nedev.

2 recordsLinked to original sources

Twinned Dynamical Decoupling

Systematic pulse-area errors limit the fidelity of quantum control across many qubit platforms. We introduce twinned dynamical decoupling (TDD), an analytic family of sequences $T2n$ in which a pulse sequence is paired with its $π$-phase-shifted twin. This $π$-phase step cancels common-mode systematic pulse-area errors to all orders on exact resonance. Then the phases of the pulses in each of the constituent twins are determined in such a manner that detuning errors are suppressed to the highest possible order as well. We have derived a simple analytic formula for these phases applicable to arbitrary sequence length. We demonstrate the sequences with superconducting transmon qubits on the IBM Quantum processor ibm$\_$torino and the IQM Quantum processor Garnet. The measured population plateaus agree closely with theory and show enhanced robustness compared to the most frequently used dynamical decoupling protocols.

quant-ph↗

Improvement of performance of Grover's algorithm on three generations of Heron family IBM QPUs without and with topological dynamical decoupling

We investigate the performance of Grover's algorithm on three different generations of IBM Heron QPUs. On Heron family of IBM QPUs the success probabilities for three, four and five qubits without dynamical decoupling is better than results reported for previous generations of QPUs. The success probability as function of number of iterations of Grover operator is considered. A study of the improvement of results of Grover's algorithm for five qubit case with the help of topological dynamical decoupling is considered. For a six qubit case on Heron r3 QPU a clear result for finding the sought-after bitstring is reported for theoretically suboptimal number of iterations of Grover operator with the help of dynamical decoupling.

quant-ph↗