• Corpus ID: 249626318

Quantum behavior of a superconducting Duffing oscillator at the dissipative phase transition

@inproceedings{Chen2022QuantumBO,
  title={Quantum behavior of a superconducting Duffing oscillator at the dissipative phase transition},
  author={Qiming Chen and Michael Fischer and Yuki Nojiri and Michael Renger and Edwar Xie and Matti Partanen and Stefan Pogorzalek and Kirill G Fedorov and Achim Marx and Frank Deppe and Rudolf Gross},
  year={2022}
}

• Qiming Chen, Michael Fischer, +8 authors Rudolf Gross
• Published 13 June 2022
• Physics

Understanding the non-deterministic behavior of deterministic nonlinear systems has been an implicit dream since Lorenz named it the “butterfly effect”. A prominent example is the hysteresis and bistability of the Duffing oscillator, which in the classical description is attributed to the coexistence of two steady states in a double-well potential. However, this interpretation fails in the quantum-mechanical perspective, where a single unique steady state is allowed in the whole parameter space. Here, we measure the non-equilibrium dynamics of a superconducting Duffing oscillator and reconcile the classical and quantum descriptions in a unified picture of quantum metastability. We demonstrate that the two classically regarded steady states are in fact metastable states. They have a remarkably long lifetime in the classical hysteresis regime we Bose-Hubbard We also reveal the two distinct phases of the transition by quantum state tomography, namely a coherent-state phase and a squeezed-state phase separated by a critical point. Our results reveal a smooth quantum state evolution behind a sudden dissipative phase transition, and they form an essential step towards understanding hysteresis and instability in non-equilibrium systems. one of the two potential wells by driving it with either a zero -amplitude (pulse-A) or a high-intensity field (pulse-C). Then, the driving strength is switched to ξ and lasts for a controllable time τ before we perform a 16 ns quadrature measurement. This procedure is repeated for more than 10 6 times to accumulate a histogram of the field quadratures. In certain experiments, we also drive the system with a constant driving field with driving strength ξ (pulse-B), which prepares the system in the SS at the initial time.