Fractionally quantized recurrence detection times in monitored quantum many-body systems

Area of Science:

• Quantum mechanics
• Condensed matter physics
• Quantum information science

Background:

• Recurrence time is crucial for understanding complex system predictability.
• Fractional quantization of recurrence times is observed in quantum systems with subspace measurements, governed by Anandan-Aharonov phases.
• This phenomenon remains unexplored in interacting quantum systems.

Purpose of the Study:

• To establish universal lower and upper bounds for recurrence times in interacting many-body spin systems.
• To explore scenarios where these bounds are approached, informing the speed of monitored quantum processes.
• To investigate the link between recurrence times, dark states, and system dynamics.

Main Methods:

• Theoretical derivation of universal bounds for recurrence times in interacting many-body spin systems.
• Analysis of specific cases mapping complex systems to single quasi-particle dynamics.
• Experimental implementation and validation on an IBM quantum computer.

Main Results:

• Universal lower and upper bounds for recurrence times in interacting many-body spin systems were established.
• In certain cases, systems map to single quasi-particle dynamics, yielding integer-quantized recurrence times.
• Experimental results on a quantum computer confirmed theoretical predictions, including fractional quantization and resilience to noise.

Conclusions:

• The study provides a deeper understanding of recurrence times in interacting quantum systems, linking them to dark states and Hilbert-space fragmentation.
• Findings demonstrate the potential for using topological fractional quantization for benchmarking quantum devices and probing dark states.
• The work highlights the robustness of quantum phenomena even in the presence of noise.