Exponentially-enhanced quantum sensing with non-Hermitian lattice dynamics

Area of Science:

• Quantum physics
• Condensed matter physics
• Quantum information science

Background:

• Non-Hermitian systems display unique phenomena absent in Hermitian systems, such as the non-Hermitian skin effect.
• Applications of non-Hermitian effects in many-mode systems for quantum sensing remain underexplored.
• Hamiltonian parameter estimation is crucial for characterizing quantum systems.

Purpose of the Study:

• To investigate the potential of non-Hermitian lattice systems for enhancing Hamiltonian parameter estimation in a quantum setting.
• To identify specific non-Hermitian models that offer significant sensing advantages.
• To explore the robustness of these advantages under non-Markovian and non-perturbative conditions.

Main Methods:

• Studying asymmetric non-Hermitian tight-binding models with a [Formula: see text] symmetry.
• Analyzing the quantum Fisher information as a measure of sensing precision.
• Evaluating the performance across various system sizes and under different physical regimes.

Main Results:

• The quintessential non-Hermitian skin effect does not provide a sensing advantage.
• Certain asymmetric non-Hermitian models yield dramatic enhancements in parameter estimation.
• Quantum Fisher information per photon increases exponentially with system size in these models.
• Advantages persist in non-Markovian and non-perturbative regimes.

Conclusions:

• Asymmetric non-Hermitian lattice systems, particularly those with [Formula: see text] symmetry, offer a powerful route to enhanced quantum sensing.
• These findings are compatible with current quantum optical and superconducting circuit platforms.
• Significant sensing enhancements are achievable even with small systems (three lattice sites).