Improving noisy free-energy measurements by adding more noise

Area of Science:

• Statistical Mechanics
• Computational Physics
• Physical Chemistry

Background:

• Estimating free-energy differences is crucial in various scientific fields.
• Nonequilibrium work relations, like the Jarzynski equality, are powerful tools for this estimation.
• Poor convergence due to large work fluctuations often hinders the accuracy of these methods.

Purpose of the Study:

• To develop a method for improving the precision of free-energy difference calculations.
• To address the challenge of poor convergence in nonequilibrium work relations.
• To propose an experimentally applicable strategy for enhanced accuracy.

Main Methods:

• Proposed adding controlled noise to systems governed by overdamped Langevin dynamics.
• Rescaled the system's potential energy to maintain thermodynamic properties.
• Analyzed the impact of added noise on relaxation rates and dissipated work using computer simulations.

Main Results:

• The addition of noise increased the system's relaxation rate.
• This modification reduced the dissipated reduced work for a given protocol.
• Achieved more accurate free-energy estimates compared to standard methods.

Conclusions:

• The proposed method of adding noise offers a counterintuitive yet effective way to enhance free-energy calculations.
• The strategy is designed for experimental implementation, demonstrated through simulations on model systems.
• Applicability is limited to experimental settings where potential energy control is feasible.