Abstract
This chapter provides a general background on the mathematical concepts used in the remainder of the thesis. We begin by discussing properties of random variables, probability distributions, and stochastic processes. We then use this framework to introduce three common methods used to model the dynamics of stochastic systems: the Master equation (for discrete-state systems), and the Fokker-Planck equation and the Langevin equation (continuous-space systems). Using these mathematical models for either trajectory- or probability distribution-level descriptions of stochastic systems, we introduce the framework of stochastic thermodynamics, and how it consistently defines physical quantities such as heat, work, and entropy for stochastic, strongly fluctuating systems. We also introduce the fluctuation theorems—a set of mathematical equalities central to the modern study of stochastic thermodynamics—and discuss their importance in modern nonequilibrium statistical mechanics, with a particular focus on the relationships between them. We further elaborate upon our discussion of entropy, introducing a number of related information-theoretical quantities that carry important physical interpretations later in the thesis. Finally, we discuss the role of control theory in nonequilibrium systems, and the historical utility of framing problems of efficient operation of molecular machines through the lens of control theory.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Notes
- 1.
For the interested reader, however, [4] provides a succinct introduction to the mathematical subject.
- 2.
Or, in the language of probability theory, each individual event represents a set of zero measure.
- 3.
See Gardiner [2] for a more in-depth discussion of these constraints, but simply put, the constraints relate to the continuity of the underlying stochastic process in the continuous-time limit.
- 4.
This is analogous, in this case, to the Gillespie algorithm used to propagate the chemical master equation.
- 5.
To get an underdamped equation of motion, we need to also include the time evolution of the distribution of velocities. The Kramers equation does just this for a 1D system, but we won’t discuss it in detail here. For the interested reader, however, an excellent overview is given in Hannes Risken’s book [12].
- 6.
In fact, this is an argument made by Jacobs in [3] for the use of differential notation for SDEs in preference to writing them in terms of derivatives. The non-differentiability of sample paths implies that the derivatives themselves don’t exist, and thus it is more mathematically consistent to write the Langevin equation (or any SDE for that matter) in differential notation, such as in (2.30).
- 7.
Specifically, the Reynolds number is defined mathematically as Re ≡ Ua∕ν where U is the speed of the object, a is a characteristic linear dimension, and ν is the kinematic viscosity of the fluid (for water, ν ≈ 10−6 m2/s). For a typical bacterium (such as, for instance, E. coli) the characteristic linear dimension is a ≈ 10−6 m and they travel at velocities of U ≈ 10−5 m/s and thus the Reynolds number is Re ≈ 10−5 [14].
- 8.
The Kolmogorov-Sinai entropy is a definition of entropy, used often in dynamical systems theory, that is calculated from the Lyapunov exponents in chaotic systems [18].
- 9.
This explanation of the entropy is clarified when the entropy is described in bits, by using base-2 logarithms. Here, the entropy is literally the average number of bits—yes or no questions—required to completely specify the state of a system.
- 10.
Actually, this represents a further subfield known as stochastic optimal control, as it pertains to optimal control strategies in stochastic systems. However, in Chap. 6 we will refer to the control of systems through stochastic driving protocols as ‘stochastic control’, and thus, to avoid confusion, we will refer to stochastic optimal control in this context simply as optimal control.
- 11.
- 12.
- 13.
Put another way, the weakness of the perturbing field ϕ ensures that it only couples linearly to the conjugate force.
- 14.
Originally, this result was derived for systems with Hamiltonian dynamics (as in, for instance, Ref. [40]), which led to skepticism about its broad applicability in microscopic systems (including a well-known critique from van Kampen in [42]). However, the linear-response predictions seemed to remain consistent with experimental observations in far more general situations than the Hamiltonian derivation would suggest. More recently, the analogous result has been derived for stochastic dynamics and nonequilibrium systems, however it is still an active area of research [43].
- 15.
We will explore the limitations of this approximation in more depth in Chap. 6, with the particular motivation of how it can fail for stochastic control protocols.
- 16.
A similar mathematical form of a friction coefficient was also derived, in a different context, by Berezhkovskii and Szabo in [49].
- 17.
As it turns out, there are mutually incompatible assumptions made with regard to the continuous limit when deriving Crooks’ Fisher information metric or the generalized friction, but we will explore and elaborate on the details of these assumptions in Sect. 7.4.1.
- 18.
To recover Crooks’ original measure of the thermodynamic length, we simply replace ζ ij(λ) in \(\mathcal {L}\) with the Fisher information matrix \(\mathcal {I}_{ij}(\boldsymbol {\lambda })\).
- 19.
References
A. Kolmogorov, Foundations of the Theory of Probability (Chelsea Publishing Company, 1950)
C. Gardiner, Stochastic Methods, A Handbook for the Natural and Social Sciences, 4th edn. (Springer, 2009)
K. Jacobs, Stochastic Processes for Physicists: Understanding Noisy Systems (Cambridge University Press, 2010)
D.W. Stroock, Probability Theory: An Analytic View (Cambridge University Press, 2010)
L.A. Wasserman, All of Statistics: A Concise Course in Statistical Inference (Springer, 2013)
N.G. van Kampen, Stochastic Processes in Physics and Chemistry, 3rd edn. (Elsevier, 2007)
I.N. Sneddon, Fourier Transforms (Dover Publications, 2010)
H. Touchette, The large deviation approach to statistical mechanics. Phys. Rep. 478, 1–69 (2009)
D. Williams, Probability with Martingales. Cambridge Mathematical Textbooks (Cambridge University Press, 1991)
R. Rao, M. Esposito, Nonequilibrium thermodynamics of chemical reaction networks: wisdom from stochastic thermodynamics. Phys. Rev. X 6, 041064 (2016)
M. Esposito, Stochastic thermodynamics under coarse graining. Phys. Rev. E 85, 041125 (2012)
H. Risken, The Fokker-Planck Equation: Methods of Solution and Applications, 2nd edn. (Springer, 2011)
L.D. Landau, E.M. Lifshitz, Fluid Dynamics, 2nd edn. (Pergamon Press, 1987)
E.M. Purcell, Life at low Reynolds number. Am. J. Phys. 45, 3–11 (1977)
K. Sekimoto, Langevin equations and thermodynamics. Prog. Theor. Phys. Supp. 130, 17 (1998)
U. Seifert, Stochastic thermodynamics, fluctuation theorems and molecular machines. Rep. Prog. Phys. 75, 126001 (2012)
C. Jarzynski, Equalities and inequalities: Irreversibility and the second law of thermodynamics at the nanoscale. Annu. Rev. Condens. Matter. Phys. 2, 329–351 (2011)
T.M. Cover, J.A. Thomas, Elements of Information Theory, 2nd edn. (Wiley, 2006)
G. Gallavotti, E.G.D. Cohen, Dynamical ensembles in nonequilibrium statistical mechanics. Phys. Rev. Lett. 74 2694 (1995)
D.J. Evans, E.G.D. Cohen, G.P. Morriss, Probability of second law violations in shearing steady states. Phys. Rev. Lett. 71, 2401 (1993)
D.J. Evans, D.J. Searles, Equilibrium microstates which generate second law violating steady states. Phys. Rev. E 50, 1645 (1994)
G.N. Bochkov, Y.E. Kuzovlev, General theory of thermal fluctuations in nonlinear systems. Sov. Phys. JETP 45, 125 (1977)
G.N. Bochkov, Y.E. Kuzovlev, Fluctuation-dissipation relations for nonequilibrium processes in open systems. Sov. Phys. JETP 49, 543 (1978)
C. Jarzynski, Nonequilibrium equality for free energy differences. Phys. Rev. Lett. 78, 2690 (1997)
G.E. Crooks, Entropy production fluctuation theorem and the nonequilibrium work relation for free energy differences. Phys. Rev. E 60, 2721 (1999)
M. Esposito, C. Van den Broeck, Three detailed fluctuation theorems. Phys. Rev. Lett. 104, 090601 (2010)
U. Seifert, Entropy production along a stochastic trajectory and an integral fluctuation theorem. Phys. Rev. Lett. 95, 040602 (2005)
M. Esposito, C. Van den Broeck, Three faces of the second law. I. Master equation formulation. Phys. Rev. E 82, 011143 (2010)
C. Van den Broeck, M. Esposito, Three faces of the second law. II. Fokker-Planck formulation. Phys. Rev. E 82, 011144 (2010)
G.E. Crooks, D.A. Sivak, Measures of trajectory ensemble disparity in nonequilibrium statistical dynamics. J. Stat. Mech. P06003 (2011)
G.F. Franklin, J.D. Powell, A. Emami-Naeini, Feedback Control of Dynamical Systems, 4th edn. (Prentice-Hall, 2002)
J.C. Maxwell, On governors. Proc. R. Soc. Lond. 16, 270–283 (1868)
J. Bechhoefer, Feedback for physicists: A tutorial essay on control. Rev. Mod. Phys. 77, 783 (2005)
K. Proesmans, J. Ehrich, J. Bechhoefer, Finite-time Landauer principle. Phys. Rev. Lett. 125, 100602 (2020)
K. Proesmans, J. Ehrich, J. Bechhoefer, Optimal finite-time bit erasure under full control. Phys. Rev. E 102, 032105 (2020)
T. Schmiedl, U. Seifert, Optimal finite-time processes in stochastic thermodynamics. Phys. Rev. Lett. 98, 108301 (2007)
E. Aurell, C. Mejía-Monasterio, P. Muratore-Ginanneschi, Optimal protocols and optimal transport in stochastic thermodynamics. Phys. Rev. Lett. 106, 250601 (2011)
E. Aurell, C. Mejía-Monasterio, P. Muratore-Ginanneschi, Boundary layers in stochastic thermodynamics. Phys. Rev. E 85, 020103(R) (2012)
D.A. Sivak, G.E. Crooks, Thermodynamic metrics and optimal paths. Phys. Rev. Lett. 108, 190602 (2012)
D. Chandler, Introduction to Modern Statistical Mechanics (Oxford University Press, 1987)
R. Zwanzig, Nonequilibrium Statistical Mechanics (Oxford University Press, 2001)
N.G. van Kampen, The case against linear response theory. Phys. Norv. 5, 279 (1971)
A. Sarracino, A. Vulpiani, On the fluctuation-dissipation relation in non-equilibrium and non-Hamiltonian systems. Chaos 29, 083132 (2019)
W.J. Rugh, Nonlinear System Theory: The Volterra-Wiener Approach (Johns Hopkins University Press, 1981)
J.G. Kirkwood, The statistical mechanical theory of transport processes I. General theory. J. Chem. Phys. 14, 180 (1964)
R. Zwanzig, Elementary derivation of time-correlation formulas for transport coefficients. J. Chem. Phys. 40, 2527 (1964)
D.A. Garanin, Integral relaxation time of single-domain ferromagnetic particles. Phys. Rev. E 54, 3250 (1996)
P.R. Zulkowski, M.R. DeWeese, Optimal finite-time erasure of a classical bit. Phys. Rev. E 89, 052140 (2014)
A. Berezhkovskii, A. Szabo, Time scale separation leads to position-dependent diffusion along a slow coordinate. J. Chem. Phys. 135, 174108 (2011)
M.J. Klein, The physics of J. Willard Gibbs in his time. Phys. Today 43(3), 40 (1990)
F. Weinhold, Metric geometry of equilibrium thermodynamics. J. Chem. Phys. 63(6), 2479–2483 (1975)
G. Ruppeiner, Thermodynamics: A Riemannian geometric model. Phys. Rev. A 20, 1608 (1979)
F. Schlögl, A connection between correlations and the order of bit-number cumulants. Z. Phys. B 59, 449 (1985)
J. Nulton, P. Salamon, B. Andresen, Q. Amin, Quasistatic processes as step equilibrations. J. Chem. Phys. 83, 334 (1985)
G.E. Crooks, Measuring thermodynamic length. Phys. Rev. Lett. 99, 100602 (2007)
G.M. Rotskoff, G.E. Crooks, Optimal control in nonequilibrium systems: Dynamic Riemannian geometry of the Ising model. Phys. Rev. E 92, 060102(R) (2015)
P.R. Zulkowski, M.R. DeWeese, Optimal control of overdamped systems. Phys. Rev. E 92, 032117 (2015)
T.R. Gingrich, J.M. Horowitz, N. Perunov, J.L. England, Dissipation bounds all steady-state current fluctuations. Phys. Rev. Lett. 116, 120601 (2016)
J.N.E. Lucero, A. Mehdizadeh, D.A. Sivak, Optimal control of rotary motors. Phys. Rev. E 99, 012119 (2019)
A.K.S. Kasper, D.A. Sivak, Modeling work-speed-accuracy trade-offs in a stochastic rotary machine. Phys. Rev. E 101, 032110 (2020)
S.J. Large, R. Chetrite, D.A. Sivak, Stochastic control in microscopic nonequilibrium systems. EPL 124, 20001 (2018)
D.A. Sivak, G.E. Crooks, Thermodynamic geometry of minimum-dissipation driven barrier crossing. Phys. Rev. E 94, 052106 (2016)
P.R. Zulkowski, D.A. Sivak, G.E. Crooks, M.R. DeWeese, Geometry of thermodynamic control. Phys. Rev. E 86, 041148 (2012)
J.E. Niven, S.B. Laughlin, Energy limitation as a selective pressure on the evolution of sensory systems. J. Exp. Biol. 211, 1792 (2008)
A.P. Solon, J.M. Horowitz, Phase transitions in protocols minimizing work fluctuations. Phys. Rev. Lett. 120, 180605 (2018)
O. Mazonka, C. Jarzynski, Exactly solvable model illustrating far-from-equilibrium predictions. (1999) arxiv:9912121
P. Reimann, Brownian motors: noisy transport far from equilibrium. Phys. Rep. 361, 57 (2002)
D. Frenkel, B. Smit, Understanding Molecular Simulation: From Algorithms to Applications, 2nd edn. (Academic Press, 2002)
K. Kawguchi, S.-I. Sasa, T. Sagawa, Nonequilibrium dissipation-free transport in F1-ATPase and the thermodynamic role of asymmetric allosterism. Biophys. J. 106, 2450 (2014)
S. Toyabe, H. Ueno, E. Muneyuki, Recovery of state-specific potential of molecular motor from single-molecule trajectory. EPL 97, 40004 (2012)
Author information
Authors and Affiliations
Rights and permissions
Copyright information
© 2021 The Author(s), under exclusive license to Springer Nature Switzerland AG
About this chapter
Cite this chapter
Large, S.J. (2021). Theoretical Background. In: Dissipation and Control in Microscopic Nonequilibrium Systems. Springer Theses. Springer, Cham. https://doi.org/10.1007/978-3-030-85825-4_2
Download citation
DOI: https://doi.org/10.1007/978-3-030-85825-4_2
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-030-85824-7
Online ISBN: 978-3-030-85825-4
eBook Packages: Physics and AstronomyPhysics and Astronomy (R0)