Parity-Dependent State Transfer and Many-Qubit Entanglement Generation on a Superconducting Qubit Chain
ORAL
Abstract
Superconducting qubit devices have recently demonstrated high-fidelity operations, high coherence times and improved scalability, making them a leading platform for quantum computing. However, practical applications require the efficient generation of many-qubit entangled states, incurring large overheads in single- and two-qubit gates as qubit connectivity is generally limited to nearest-neighbor pairs. Nonetheless, by evolving the system under simultaneous local interactions, one can realize effective non-local multi-qubit operations, efficiently generating entanglement. In this work, we operate a circuit of six fixed-frequency transmons with tunable couplers and control the couplings via simultaneous parametric drives. We engineer the drive amplitudes and frequencies in order to implement a quantum state transfer protocol, in which excitations are coherently transferred between distant qubits. We observe the parity-dependent property of the transfer, where the number of excitations within the chain controls the phase of the transferred state. Finally, we utilize this property to prepare multi-qubit GHZ states with Hadamard gates and a single transfer operation, demonstrating efficient entanglement generation.
**We acknowledge financial support from the German Federal Ministry of Education and Research via the funding program quantum technologies - from basic research to the market under contract number 13N15680 "GeQCoS" and under contract number 13N16188 "MUNIQC-SC" as well as by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) via project number FI2549/1-1 and the Germany's Excellence Strategy EXC-2111-390814868 'MCQST'. The research is part of the Munich Quantum Valley, which is supported by the Bavarian state government with funds from the Hightech Agenda Bayern Plus.
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Presenters
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João H Romeiro
- Walther-Meißner-Institut & TU Munich