To catch and reverse a quantum jump mid-flight

Area of Science:

• Quantum Physics
• Atomic Physics
• Quantum Optics

Background:

• Quantum measurements yield discrete and random results, exemplified by quantum jumps between atomic energy levels.
• Quantum jumps were experimentally observed in atomic ions under specific measurement conditions.
• The timing of quantum jumps has been considered fundamentally unpredictable.

Purpose of the Study:

• To investigate if quantum jumps, despite their non-deterministic nature, can be predicted.
• To experimentally demonstrate the possibility of tracking and intervening in quantum jumps.
• To explore real-time control techniques for quantum systems.

Main Methods:

• Experimentally tracking quantum jumps in a superconducting artificial three-level atom.
• Monitoring the population of an auxiliary energy level coupled to the ground state.
• Utilizing real-time monitoring and feedback to intervene in quantum jumps mid-flight.

Main Results:

• Demonstrated that quantum jumps follow a predictable 'flight' path.
• Showed that the evolution of completed quantum jumps is continuous, coherent, and deterministic.
• Successfully caught and reversed quantum jumps mid-flight using real-time feedback.

Conclusions:

• Quantum jumps can be predicted and controlled in real-time.
• Findings support modern quantum trajectory theory and its predictions.
• Opens new avenues for real-time intervention in quantum systems, including quantum error correction.