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Hidden two-qubit dynamics of a four-level Josephson circuit
Elisha Svetitsky1, Haim Suchowski2, Roy Resh1
1Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Nature Communications
|November 26, 2014
Summary
Group theory simplifies complex quantum dynamics using a
Area of Science:
- Quantum Information Science
- Quantum Control
Background:
- Multi-level quantum coherence control offers significant resource reduction for quantum information science applications.
- Complex dynamics arise in multi-level quantum systems, necessitating intuitive control strategies.
Purpose of the Study:
- To simplify and visualize complex four-level quantum dynamics using group theory.
- To demonstrate precise control of a Josephson phase qudit using multi-tone excitation.
- To explore the dynamical evolution and entanglement in a multi-level system.
Main Methods:
- Employing group theory to visualize dynamics in a 'Bell frame' of effective two-level qubits.
- Utilizing a single multi-tone excitation for controlling a Josephson phase qudit.
- Analyzing system dynamics via Cartan gate decomposition.
Main Results:
- Achieved successive population inversions between the first and third levels of the qudit.
- Demonstrated constraints imposed by the effective two-qubit representation.
- Observed entangling-disentangling oscillations due to finite anharmonicity, explained by Cartan gate decomposition.
Conclusions:
- The 'Bell frame' provides an intuitive framework for understanding and controlling multi-level quantum dynamics.
- Group theory visualization aids in managing the complexity of quantum coherence control.
- The demonstrated control method and theoretical framework offer a promising approach for quantum information processing.
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