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Stochastic Thermodynamics in Mesoscopic Chemical Oscillation Systems. Zhonghuai Hou ( 侯中怀 ) 2009.12 XiaMen Email: hzhlj@ustc.edu.cn Department of Chemical Physics Hefei National Lab for Physical Science at Microscale University of Science & Technology of China (USTC).
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Stochastic Thermodynamics in Mesoscopic Chemical Oscillation Systems Zhonghuai Hou (侯中怀) 2009.12 XiaMen Email: hzhlj@ustc.edu.cn Department of Chemical Physics Hefei National Lab for Physical Science at Microscale University of Science & Technology of China (USTC)
Our Research Interests • Nonlinear Dynamics in Mesoscopic Chemical Systems • Dynamics of/on Complex Networks • Nonequilibrium Thermodynamics of Small Systems (Fluctuation Theorem) • Mesoscopic Modeling of Complex Systems Nonequilibrium + Nonlinearity + Complexity
Irreversibility Paradox ? Microscopic Reversibility Macroscopic Time Arrow t-t, p-p the 2nd law How the second law emerges as the system size grows? Key: Thermodynamics of Small Systems ! Molecular Motors 2~100nm Solid Clusters 1~10nm Quantum Dots 2~100nm Subcellular reactions…
Small Systems? • Fluctuations begin to dominate • Heat, Work: Stochastic Variables • Distribution is more important Polymer Stretching Protocol:X(t) Heat Work Physics Today, 58, 43, July 2005
Fluctuation Theorem Nonequilibrium Steady States • Second Law: • Must have P(-)>0 Second law violation ‘events’ • P(+)/P(-) grows exponentially with size and time • For large system and long time, the 2nd Law holds overwhelmingly • For small system and short time, 2nd Law violating fluctuations is possible (Molecular motor) Adv. In Phys. 51, 1529(2002); Annu. Rev. Phys. Chem. 59, 603(2008); ……
Stochastic Thermodynamics (ST) Stochastic process(Single path based) A Random Trajectory Trajectory Entropy Total Entropy Change Exchange heat Fluctuation Theorems Second Law Prof. Udo Seifert
Many Applications…… • Probing molecular free energy landscapes by periodic loading PRL(2004) • Entropy production along a stochastic trajectory and an integral fluctuation theorem , PRL (2005) • Experimental test of the fluctuation theorem for a driven two-level system with time-dependent rates, PRL (2005) • Thermodynamics of a colloidal particle in a time-dependent non-harmonic potential, PRL(2006) • Measurement of stochastic entropy production, PRL(2006) • Optimal Finite-Time Processes In Stochastic Thermodynamics, PRL(2007) • Stochastic thermodynamics of chemical reaction networks, JCP(2007) • Role of external flow and frame invariance in stochastic thermodynamics, PRL(2008) • Recent Review: EPJB(2008)
Our Work Stochastic Thermodynamics Chemical Oscillation Systems
Chemical Oscillation • Self-Organization far from Equilibrium • Important: signaling, catalysis • Nanosystems: Fluctuation matters Synthetic Gene Oscillator CO+O2 Rate Oscillation
Modeling of Chemical Oscillations • Macro- Kinetics: Deterministic, Cont. N Species, M reaction channels, well-stirred in V Reaction j: Rate: Hopf bifurcation Nonequilibrium Phase Transition (NPT)
Modeling of Chemical Oscillations Exactly Kinetic Monte Carlo Simulation (KMC) Gillespie’s algorithm Approximately Internal Noise Deterministic kinetic equation • Mesoscopic Level: Stochastic, Discrete Master Equation
Our concern… N, V (Small) How ST applies ? Fluctuation Theorem ? Second law? Role of Bifurcation? • Small • Far From • Equilibrium • Stochastic • Process ……
The Brusselator Concentration: Stochastic Oscillation Molecular number: State Space Random Walk
Path and Entropy Master Equation: Random Path:Gillespie Algorithm Entropy: Dynamic Irreversibility
Entropy Change Along Limit Cycle Stochastic Oscillation: Closed Orbit (Limit Cycle) • Distribution not sensitive to Hopf Bifurcation (HB) • 2nd-Law Violation Events happens( ) • Second Law:
NPT: Scaling Change Abruptly Role of HB? Entropy Production Above HB Below HB Universal for Oscillation Systems? Entropy production and fluctuation theorem along a stochastic limit cycle T Xiao, Z. Hou, H. Xin. J. Chem. Phys. 129, 114508(Sep 2008)
General Meso-Oscillation Systems Chemical Langevin Euqations(CLE): Fokker-PlanckEquations(FPE):
Path Integral … Trajectory Entropy Entropy Change Along Path: Total System Medium Entropy Production
Stochastic Normal Form Theory Centre Manifold: Oscillatory Motion Stable Manifold: Decay Much faster T Xiao, Z. Hou, H. Xin. ChemPhysChem 7, 1520(2006); New J. Phys. 9, 407(2007)
Analytical Result Slow Oscillatory Mode Dominants
Scaling Relations: Universal Normal form theory tells: Scaling relation
General Picture Universal FT Holds Stochastic Thermodynamics in mesoscopic chemical oscillation systems T Xiao, Z. Hou, H. Xin. J. Phys. Chem. B 113, 9316(2009)
Concluding Remarks • ST applies to mesoscopic oscillation systems with trajectory reversibility • Oscillatory motion(circular flux) leads to the dynamic irreversibility • FT holds for the total entropy change along a stochastic limit cycle • The scaling of E.P. with V changes abruptly at the HB (NPT), which can be explained by the stochastic normal form theory
Acknowledgements Support: National science foundation of China Thank you Detail work: Dr. Tiejun Xiao (肖铁军)