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Scalable Quantum Integrated Circuits on Superconducting Two-Dimensional Electron Gas Platform
Published on: August 2, 2019
Measurement- and Feedback-Driven Nonequilibrium Phase Transitions on a Quantum Processor
Zhiyi Wu1,2, Xuandong Sun2,3, Songlei Wang1
1Peking University, School of Physics, Beijing 100871, China.
Physical Review Letters
|July 23, 2026
Summary
This study demonstrates novel quantum phase transitions using a superconducting quantum processor with fast, high-fidelity midcircuit measurements. The research reveals distinct absorbing-state and measurement-induced entanglement transitions in quantum many-body dynamics.
Area of Science:
- Quantum Computing
- Quantum Many-Body Dynamics
- Condensed Matter Physics
Background:
- Midcircuit measurements and feedback are crucial for quantum error correction.
- Integrating these operations into quantum many-body dynamics can lead to novel nonequilibrium phase transitions.
- Experimental realization of these transitions is challenging due to fidelity and latency limitations.
Purpose of the Study:
- To develop a quantum computing platform enabling high-fidelity, low-latency midcircuit measurements and feedback.
- To experimentally investigate the coexistence of different quantum phase transitions in nonequilibrium systems.
- To explore adaptive quantum circuits for studying complex quantum dynamics.
Main Methods:
- Development of a superconducting quantum processor with global midcircuit measurement capabilities.
- Achieved 98.7% average quantum nondemolition (QND) fidelity for measurements.
- Implemented fast conditional feedback with 200 ns real-time decision latency.
Main Results:
- Demonstrated the coexistence of an absorbing-state transition and a measurement-induced entanglement transition.
- Observed these transitions at the quantum channel and individual quantum trajectory levels, respectively.
- Extracted critical exponents for the absorbing-state transition, matching the directed percolation universality class.
Conclusions:
- Adaptive quantum circuits are a powerful tool for exploring nonequilibrium quantum many-body dynamics.
- The developed platform facilitates the experimental study of complex quantum phenomena.
- Distinct critical behaviors were observed for different types of quantum phase transitions.
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