Statistical Physics Syllabus Lectures and Recitations
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Canonical Ensemble
ME346A Introduction to Statistical Mechanics { Wei Cai { Stanford University { Win 2011 Handout 8. Canonical Ensemble January 26, 2011 Contents Outline • In this chapter, we will establish the equilibrium statistical distribution for systems maintained at a constant temperature T , through thermal contact with a heat bath. • The resulting distribution is also called Boltzmann's distribution. • The canonical distribution also leads to definition of the partition function and an expression for Helmholtz free energy, analogous to Boltzmann's Entropy formula. • We will study energy fluctuation at constant temperature, and witness another fluctuation- dissipation theorem (FDT) and finally establish the equivalence of micro canonical ensemble and canonical ensemble in the thermodynamic limit. (We first met a mani- festation of FDT in diffusion as Einstein's relation.) Reading Assignment: Reif x6.1-6.7, x6.10 1 1 Temperature For an isolated system, with fixed N { number of particles, V { volume, E { total energy, it is most conveniently described by the microcanonical (NVE) ensemble, which is a uniform distribution between two constant energy surfaces. const E ≤ H(fq g; fp g) ≤ E + ∆E ρ (fq g; fp g) = i i (1) mc i i 0 otherwise Statistical mechanics also provides the expression for entropy S(N; V; E) = kB ln Ω. In thermodynamics, S(N; V; E) can be transformed to a more convenient form (by Legendre transform) of Helmholtz free energy A(N; V; T ), which correspond to a system with constant N; V and temperature T . Q: Does the transformation from N; V; E to N; V; T have a meaning in statistical mechanics? A: The ensemble of systems all at constant N; V; T is called the canonical NVT ensemble. -
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Arxiv:1509.06955V1 [Physics.Optics]
Statistical mechanics models for multimode lasers and random lasers F. Antenucci 1,2, A. Crisanti2,3, M. Ib´a˜nez Berganza2,4, A. Marruzzo1,2, L. Leuzzi1,2∗ 1 NANOTEC-CNR, Institute of Nanotechnology, Soft and Living Matter Lab, Rome, Piazzale A. Moro 2, I-00185, Roma, Italy 2 Dipartimento di Fisica, Universit`adi Roma “Sapienza,” Piazzale A. Moro 2, I-00185, Roma, Italy 3 ISC-CNR, UOS Sapienza, Piazzale A. Moro 2, I-00185, Roma, Italy 4 INFN, Gruppo Collegato di Parma, via G.P. Usberti, 7/A - 43124, Parma, Italy We review recent statistical mechanical approaches to multimode laser theory. The theory has proved very effective to describe standard lasers. We refer of the mean field theory for passive mode locking and developments based on Monte Carlo simulations and cavity method to study the role of the frequency matching condition. The status for a complete theory of multimode lasing in open and disordered cavities is discussed and the derivation of the general statistical models in this framework is presented. When light is propagating in a disordered medium, the system can be analyzed via the replica method. For high degrees of disorder and nonlinearity, a glassy behavior is expected at the lasing threshold, providing a suggestive link between glasses and photonics. We describe in details the results for the general Hamiltonian model in mean field approximation and mention an available test for replica symmetry breaking from intensity spectra measurements. Finally, we summary some perspectives still opened for such approaches. The idea that the lasing threshold can be understood as a proper thermodynamic transition goes back since the early development of laser theory and non-linear optics in the 1970s, in particular in connection with modulation instability (see, e.g.,1 and the review2). -
Conclusion: the Impact of Statistical Physics
Conclusion: The Impact of Statistical Physics Applications of Statistical Physics The different examples which we have treated in the present book have shown the role played by statistical mechanics in other branches of physics: as a theory of matter in its various forms it serves as a bridge between macroscopic physics, which is more descriptive and experimental, and microscopic physics, which aims at finding the principles on which our understanding of Nature is based. This bridge can be crossed fruitfully in both directions, to explain or predict macroscopic properties from our knowledge of microphysics, and inversely to consolidate the microscopic principles by exploring their more or less distant macroscopic consequences which may be checked experimentally. The use of statistical methods for deductive purposes becomes unavoidable as soon as the systems or the effects studied are no longer elementary. Statistical physics is a tool of common use in the other natural sciences. Astrophysics resorts to it for describing the various forms of matter existing in the Universe where densities are either too high or too low, and tempera tures too high, to enable us to carry out the appropriate laboratory studies. Chemical kinetics as well as chemical equilibria depend in an essential way on it. We have also seen that this makes it possible to calculate the mechan ical properties of fluids or of solids; these properties are postulated in the mechanics of continuous media. Even biophysics has recourse to it when it treats general properties or poorly organized systems. If we turn to the domain of practical applications it is clear that the technology of materials, a science aiming to develop substances which have definite mechanical (metallurgy, plastics, lubricants), chemical (corrosion), thermal (conduction or insulation), electrical (resistance, superconductivity), or optical (display by liquid crystals) properties, has a great interest in statis tical physics. -
Research Statement Statistical Physics Methods and Large Scale
Research Statement Maxim Shkarayev Statistical physics methods and large scale computations In recent years, the methods of statistical physics have found applications in many seemingly un- related areas, such as in information technology and bio-physics. The core of my recent research is largely based on developing and utilizing these methods in the novel areas of applied mathemat- ics: evaluation of error statistics in communication systems and dynamics of neuronal networks. During the coarse of my work I have shown that the distribution of the error rates in the fiber op- tical communication systems has broad tails; I have also shown that the architectural connectivity of the neuronal networks implies the functional connectivity of the afore mentioned networks. In my work I have successfully developed and applied methods based on optimal fluctuation theory, mean-field theory, asymptotic analysis. These methods can be used in investigations of related areas. Optical Communication Systems Error Rate Statistics in Fiber Optical Communication Links. During my studies in the Ap- plied Mathematics Program at the University of Arizona, my research was focused on the analyti- cal, numerical and experimental study of the statistics of rare events. In many cases the event that has the greatest impact is of extremely small likelihood. For example, large magnitude earthquakes are not at all frequent, yet their impact is so dramatic that understanding the likelihood of their oc- currence is of great practical value. Studying the statistical properties of rare events is nontrivial because these events are infrequent and there is rarely sufficient time to observe the event enough times to assess any information about its statistics. -
Statistical Physics– a Second Course
Statistical Physics– a second course Finn Ravndal and Eirik Grude Flekkøy Department of Physics University of Oslo September 3, 2008 2 Contents 1 Summary of Thermodynamics 5 1.1 Equationsofstate .......................... 5 1.2 Lawsofthermodynamics. 7 1.3 Maxwell relations and thermodynamic derivatives . .... 9 1.4 Specificheatsandcompressibilities . 10 1.5 Thermodynamicpotentials . 12 1.6 Fluctuations and thermodynamic stability . .. 15 1.7 Phasetransitions ........................... 16 1.8 EntropyandGibbsParadox. 18 2 Non-Interacting Particles 23 1 2.1 Spin- 2 particlesinamagneticfield . 23 2.2 Maxwell-Boltzmannstatistics . 28 2.3 Idealgas................................ 32 2.4 Fermi-Diracstatistics. 35 2.5 Bose-Einsteinstatistics. 36 3 Statistical Ensembles 39 3.1 Ensemblesinphasespace . 39 3.2 Liouville’stheorem . .. .. .. .. .. .. .. .. .. .. 42 3.3 Microcanonicalensembles . 45 3.4 Free particles and multi-dimensional spheres . .... 48 3.5 Canonicalensembles . 50 3.6 Grandcanonicalensembles . 54 3.7 Isobaricensembles .......................... 58 3.8 Informationtheory . .. .. .. .. .. .. .. .. .. .. 62 4 Real Gases and Liquids 67 4.1 Correlationfunctions. 67 4.2 Thevirialtheorem .......................... 73 4.3 Mean field theory for the van der Waals equation . 76 4.4 Osmosis ................................ 80 3 4 CONTENTS 5 Quantum Gases and Liquids 83 5.1 Statisticsofidenticalparticles. .. 83 5.2 Blackbodyradiationandthephotongas . 88 5.3 Phonons and the Debye theory of specific heats . 96 5.4 Bosonsatnon-zerochemicalpotential . -
Statistical Physics II
Statistical Physics II. Janos Polonyi Strasbourg University (Dated: May 9, 2019) Contents I. Equilibrium ensembles 3 A. Closed systems 3 B. Randomness and macroscopic physics 5 C. Heat exchange 6 D. Information 8 E. Correlations and informations 11 F. Maximal entropy principle 12 G. Ensembles 13 H. Second law of thermodynamics 16 I. What is entropy after all? 18 J. Grand canonical ensemble, quantum case 19 K. Noninteracting particles 20 II. Perturbation expansion 22 A. Exchange correlations for free particles 23 B. Interacting classical systems 27 C. Interacting quantum systems 29 III. Phase transitions 30 A. Thermodynamics 32 B. Spontaneous symmetry breaking and order parameter 33 C. Singularities of the partition function 35 IV. Spin models on lattice 37 A. Effective theories 37 B. Spin models 38 C. Ising model in one dimension 39 D. High temperature expansion for the Ising model 41 E. Ordered phase in the Ising model in two dimension dimensions 41 V. Critical phenomena 43 A. Correlation length 44 B. Scaling laws 45 C. Scaling laws from the correlation function 47 D. Landau-Ginzburg double expansion 49 E. Mean field solution 50 F. Fluctuations and the critical point 55 VI. Bose systems 56 A. Noninteracting bosons 56 B. Phases of Helium 58 C. He II 59 D. Energy damping in super-fluid 60 E. Vortices 61 VII. Nonequillibrium processes 62 A. Stochastic processes 62 B. Markov process 63 2 C. Markov chain 64 D. Master equation 65 E. Equilibrium 66 VIII. Brownian motion 66 A. Diffusion equation 66 B. Fokker-Planck equation 68 IX. Linear response 72 A. -
Physics/9803005
UWThPh-1997-52 27. Oktober 1997 History and outlook of statistical physics 1 Dieter Flamm Institut f¨ur Theoretische Physik der Universit¨at Wien, Boltzmanngasse 5, 1090 Vienna, Austria Email: [email protected] Abstract This paper gives a short review of the history of statistical physics starting from D. Bernoulli’s kinetic theory of gases in the 18th century until the recent new developments in nonequilibrium kinetic theory in the last decades of this century. The most important contributions of the great physicists Clausius, Maxwell and Boltzmann are sketched. It is shown how the reversibility and the recurrence paradox are resolved within Boltzmann’s statistical interpretation of the second law of thermodynamics. An approach to classical and quantum statistical mechanics is outlined. Finally the progress in nonequilibrium kinetic theory in the second half of this century is sketched starting from the work of N.N. Bogolyubov in 1946 up to the progress made recently in understanding the diffusion processes in dense fluids using computer simulations and analytical methods. arXiv:physics/9803005v1 [physics.hist-ph] 4 Mar 1998 1Paper presented at the Conference on Creativity in Physics Education, on August 23, 1997, in Sopron, Hungary. 1 In the 17th century the physical nature of the air surrounding the earth was es- tablished. This was a necessary prerequisite for the formulation of the gas laws. The invention of the mercuri barometer by Evangelista Torricelli (1608–47) and the fact that Robert Boyle (1627–91) introduced the pressure P as a new physical variable where im- portant steps. Then Boyle–Mariotte’s law PV = const. -
Kinetic Derivation of Cahn-Hilliard Fluid Models Vincent Giovangigli
Kinetic derivation of Cahn-Hilliard fluid models Vincent Giovangigli To cite this version: Vincent Giovangigli. Kinetic derivation of Cahn-Hilliard fluid models. 2021. hal-03323739 HAL Id: hal-03323739 https://hal.archives-ouvertes.fr/hal-03323739 Preprint submitted on 22 Aug 2021 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Kinetic derivation of Cahn-Hilliard fluid models Vincent Giovangigli CMAP–CNRS, Ecole´ Polytechnique, Palaiseau, FRANCE Abstract A compressible Cahn-Hilliard fluid model is derived from the kinetic theory of dense gas mixtures. The fluid model involves a van der Waals/Cahn-Hilliard gradi- ent energy, a generalized Korteweg’s tensor, a generalized Dunn and Serrin heat flux, and Cahn-Hilliard diffusive fluxes. Starting form the BBGKY hierarchy for gas mix- tures, a Chapman-Enskog method is used—with a proper scaling of the generalized Boltzmann equations—as well as higher order Taylor expansions of pair distribu- tion functions. An Euler/van der Waals model is obtained at zeroth order while the Cahn-Hilliard fluid model is obtained at first order involving viscous, heat and diffu- sive fluxes. The Cahn-Hilliard extra terms are associated with intermolecular forces and pair interaction potentials. -
Transitions Still to Be Made Philip Ball
impacts Transitions still to be made Philip Ball A collection of many particles all interacting according to simple, local rules can show behaviour that is anything but simple or predictable. Yet such systems constitute most of the tangible Universe, and the theories that describe them continue to represent one of the most useful contributions of physics. hysics in the twentieth century will That such a versatile discipline as statisti- probably be remembered for quantum cal physics should have remained so well hid- Pmechanics, relativity and the Standard den that only aficionados recognize its Model of particle physics. Yet the conceptual importance is a puzzle for science historians framework within which most physicists to ponder. (The topic has, for example, in operate is not necessarily defined by the first one way or another furnished 16 Nobel of these and makes reference only rarely to the prizes in physics and chemistry.) Perhaps it second two. The advances that have taken says something about the discipline’s place in cosmology, high-energy physics and humble beginnings, stemming from the quantum theory are distinguished in being work of Rudolf Clausius, James Clerk important not only scientifically but also Maxwell and Ludwig Boltzmann on the philosophically, and surely that is why they kinetic theory of gases. In attempting to have impinged so forcefully on the derive the gas laws of Robert Boyle and consciousness of our culture. Joseph Louis Gay-Lussac from an analysis of But the central scaffold of modern the energy and motion of individual physics is a less familiar construction — one particles, Clausius was putting thermody- that does not bear directly on the grand ques- namics on a microscopic basis. -
Kinetic Theory of Gases and Thermodynamics
Kinetic Theory of Gases Thermodynamics State Variables Kinetic Theory of Gases and Thermodynamics Zeroth law of thermodynamics Reversible and Irreversible processes Bedanga Mohanty First law of Thermodynamics Second law of Thermodynamics School of Physical Sciences Entropy NISER, Jatni, Orissa Thermodynamic Potential Course on Kinetic Theory of Gasses and Thermodynamics - P101 Third Law of Thermodynamics Phase diagram 1/112 Principles of thermodynamics, thermodynamic state, extensive/intensive variables. internal energy, Heat, work First law of thermodynamics, heat engines Second law of thermodynamics, entropy Thermodynamic potentials References: Thermodynamics, kinetic theory and statistical thermodynamics by Francis W. Sears, Gerhard L. Salinger Thermodynamics and introduction to thermostatistics, Herbert B. Callen Heat and Thermodynamics: an intermediate textbook by Mark W. Zemansky and Richard H. Dittman About 5-7 Tutorials One Quiz (10 Marks) and 2 Assignments (5 Marks) End Semester Exam (40 Marks) Course Content Suppose to be 12 lectures. Kinetic Theory of Gases Kinetic Theory of Gases Thermodynamics State Variables Zeroth law of thermodynamics Reversible and Irreversible processes First law of Thermodynamics Second law of Thermodynamics Entropy Thermodynamic Potential Third Law of Thermodynamics Phase diagram 2/112 internal energy, Heat, work First law of thermodynamics, heat engines Second law of thermodynamics, entropy Thermodynamic potentials References: Thermodynamics, kinetic theory and statistical thermodynamics by Francis W. Sears, Gerhard L. Salinger Thermodynamics and introduction to thermostatistics, Herbert B. Callen Heat and Thermodynamics: an intermediate textbook by Mark W. Zemansky and Richard H. Dittman About 5-7 Tutorials One Quiz (10 Marks) and 2 Assignments (5 Marks) End Semester Exam (40 Marks) Course Content Suppose to be 12 lectures. -
2. Classical Gases
2. Classical Gases Our goal in this section is to use the techniques of statistical mechanics to describe the dynamics of the simplest system: a gas. This means a bunch of particles, flying around in a box. Although much of the last section was formulated in the language of quantum mechanics, here we will revert back to classical mechanics. Nonetheless, a recurrent theme will be that the quantum world is never far behind: we’ll see several puzzles, both theoretical and experimental, which can only truly be resolved by turning on ~. 2.1 The Classical Partition Function For most of this section we will work in the canonical ensemble. We start by reformu- lating the idea of a partition function in classical mechanics. We’ll consider a simple system – a single particle of mass m moving in three dimensions in a potential V (~q ). The classical Hamiltonian of the system3 is the sum of kinetic and potential energy, p~ 2 H = + V (~q ) 2m We earlier defined the partition function (1.21) to be the sum over all quantum states of the system. Here we want to do something similar. In classical mechanics, the state of a system is determined by a point in phase space.Wemustspecifyboththeposition and momentum of each of the particles — only then do we have enough information to figure out what the system will do for all times in the future. This motivates the definition of the partition function for a single classical particle as the integration over phase space, 1 3 3 βH(p,q) Z = d qd pe− (2.1) 1 h3 Z The only slightly odd thing is the factor of 1/h3 that sits out front. -
3.3 BBGKY Hierarchy
ABSTRACT CHAO, JINGYI. Transport Properties of Strongly Interacting Quantum Fluids: From CFL Quark Matter to Atomic Fermi Gases. (Under the direction of Thomas Sch¨afer.) Kinetic theory is a theoretical approach starting from the first principle, which is par- ticularly suit to study the transport coefficients of the dilute fluids. Under the framework of kinetic theory, two distinct topics are explored in this dissertation. CFL Quark Matter We compute the thermal conductivity of color-flavor locked (CFL) quark matter. At temperatures below the scale set by the gap in the quark spec- trum, transport properties are determined by collective modes. We focus on the contribu- tion from the lightest modes, the superfluid phonon and the massive neutral kaon. We find ∼ × 26 8 −6 −1 −1 −1 that the thermal conductivity due to phonons is 1:04 10 µ500 ∆50 erg cm s K ∼ × 21 4 1=2 −5=2 −1 −1 −1 and the contribution of kaons is 2:81 10 fπ;100 TMeV m10 erg cm s K . Thereby we estimate that a CFL quark matter core of a compact star becomes isothermal on a timescale of a few seconds. Atomic Fermi Gas In a dilute atomic Fermi gas, above the critical temperature, Tc, the elementary excitations are fermions, whereas below Tc, the dominant excitations are phonons. We find that the thermal conductivity in the normal phase at unitarity is / T 3=2 but is / T 2 in the superfluid phase. At high temperature the Prandtl number, the ratio of the momentum and thermal diffusion constants, is 2=3.