Optimized Trajectory Unraveling for Classical Simulation of Noisy Quantum Dynamics

Area of Science:

• Quantum Information Science
• Computational Physics
• Condensed Matter Theory

Background:

• Open quantum systems are simulated using ensembles of pure state trajectories.
• Nonunitary monitored evolution in these systems can exhibit measurement-induced entanglement phase transitions.

Purpose of the Study:

• To demonstrate that optimizing unraveling schemes can lower the entanglement phase transition threshold.
• To enable efficient classical simulation of open quantum dynamics for a broader range of decoherence rates.

Main Methods:

• Analytical derivation of optimal unraveling basis for noisy random unitary circuits.
• Development of a heuristic algorithm for adaptive optimization of unraveling basis.
• Application of heuristic approach to noisy Hamiltonian dynamics and matrix product states.

Main Results:

• Optimized unraveling schemes significantly lower the entanglement phase transition threshold.
• Heuristic algorithm extends the regime of efficient classical simulation for open quantum systems.
• Quasi-local unraveling shows potential for simulating systems with arbitrarily small decoherence rates.

Conclusions:

• Optimized unraveling is a powerful tool for simulating open quantum systems.
• The developed heuristic algorithm enhances the efficiency and applicability of classical simulations.
• Further research into quasi-local unraveling could unlock simulations of highly decoherent systems.