Non-equilibrium Dynamics of Tunnel-Coupled Superfluids

Non-equilibrium Dynamics of Tunnel-Coupled Superfluids

Author: Marine Pigneur

Publisher: Springer Nature

Published: 2020-08-28

Total Pages: 204

ISBN-13: 3030528448

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The relaxation of isolated quantum many-body systems is a major unsolved problem of modern physics, which is connected to many fundamental questions. However, realizations of quantum many-body systems which are both well isolated from their environment and accessible to experimental study are scarce. In recent years, the field has experienced rapid progress, partly attributed to ultra-cold atoms. This book presents the experimental study of a relaxation phenomenon occurring in a one-dimensional bosonic Josephson junction. The system consists of two 1D quasi Bose-Einstein condensates of 87Rb, magnetically trapped on an atom chip. Using radio-frequency dressing, the author deforms a single harmonic trap, in which the atoms are initially condensed, into a double-well potential and realizes a splitting of the wave function. A large spatial separation and a tilt of the double-well enable the preparation of a broad variety of initial states by precisely adjusting the initial population and relative phase of the two wave packets, while preserving the phase coherence. By re-coupling the two wave packets, the author investigates tunneling regimes such as Josephson (plasma) oscillations and macroscopic quantum self-trapping. In both regimes, the tunneling dynamics exhibits a relaxation to a phase-locked equilibrium state contradicting theoretical predictions. The experimental results are supported with an empirical model that allows quantitative discussions according to various experimental parameters. These results illustrate how strongly the non-equilibrium dynamics differ from the equilibrium one, which is well described by thermodynamics and statistical physics.


Book Synopsis Non-equilibrium Dynamics of Tunnel-Coupled Superfluids by : Marine Pigneur

Download or read book Non-equilibrium Dynamics of Tunnel-Coupled Superfluids written by Marine Pigneur and published by Springer Nature. This book was released on 2020-08-28 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: The relaxation of isolated quantum many-body systems is a major unsolved problem of modern physics, which is connected to many fundamental questions. However, realizations of quantum many-body systems which are both well isolated from their environment and accessible to experimental study are scarce. In recent years, the field has experienced rapid progress, partly attributed to ultra-cold atoms. This book presents the experimental study of a relaxation phenomenon occurring in a one-dimensional bosonic Josephson junction. The system consists of two 1D quasi Bose-Einstein condensates of 87Rb, magnetically trapped on an atom chip. Using radio-frequency dressing, the author deforms a single harmonic trap, in which the atoms are initially condensed, into a double-well potential and realizes a splitting of the wave function. A large spatial separation and a tilt of the double-well enable the preparation of a broad variety of initial states by precisely adjusting the initial population and relative phase of the two wave packets, while preserving the phase coherence. By re-coupling the two wave packets, the author investigates tunneling regimes such as Josephson (plasma) oscillations and macroscopic quantum self-trapping. In both regimes, the tunneling dynamics exhibits a relaxation to a phase-locked equilibrium state contradicting theoretical predictions. The experimental results are supported with an empirical model that allows quantitative discussions according to various experimental parameters. These results illustrate how strongly the non-equilibrium dynamics differ from the equilibrium one, which is well described by thermodynamics and statistical physics.

Non-equilibrium Dynamics of One-Dimensional Bose Gases

Non-equilibrium Dynamics of One-Dimensional Bose Gases

Author: Tim Langen

Publisher: Springer

Published: 2015-05-22

Total Pages: 154

ISBN-13: 3319185640

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This work presents a series of experiments with ultracold one-dimensional Bose gases, which establish said gases as an ideal model system for exploring a wide range of non-equilibrium phenomena. With the help of newly developed tools, like full distributions functions and phase correlation functions, the book reveals the emergence of thermal-like transient states, the light-cone-like emergence of thermal correlations and the observation of generalized thermodynamic ensembles. This points to a natural emergence of classical statistical properties from the microscopic unitary quantum evolution, and lays the groundwork for a universal framework of non-equilibrium physics. The thesis investigates a central question that is highly contested in quantum physics: how and to which extent does an isolated quantum many-body system relax? This question arises in many diverse areas of physics, and many of the open problems appear at vastly different energy, time and length scales, ranging from high-energy physics and cosmology to condensed matter and quantum information. A key challenge in attempting to answer this question is the scarcity of quantum many-body systems that are both well isolated from the environment and accessible for experimental study.


Book Synopsis Non-equilibrium Dynamics of One-Dimensional Bose Gases by : Tim Langen

Download or read book Non-equilibrium Dynamics of One-Dimensional Bose Gases written by Tim Langen and published by Springer. This book was released on 2015-05-22 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work presents a series of experiments with ultracold one-dimensional Bose gases, which establish said gases as an ideal model system for exploring a wide range of non-equilibrium phenomena. With the help of newly developed tools, like full distributions functions and phase correlation functions, the book reveals the emergence of thermal-like transient states, the light-cone-like emergence of thermal correlations and the observation of generalized thermodynamic ensembles. This points to a natural emergence of classical statistical properties from the microscopic unitary quantum evolution, and lays the groundwork for a universal framework of non-equilibrium physics. The thesis investigates a central question that is highly contested in quantum physics: how and to which extent does an isolated quantum many-body system relax? This question arises in many diverse areas of physics, and many of the open problems appear at vastly different energy, time and length scales, ranging from high-energy physics and cosmology to condensed matter and quantum information. A key challenge in attempting to answer this question is the scarcity of quantum many-body systems that are both well isolated from the environment and accessible for experimental study.

Universal Themes of Bose-Einstein Condensation

Universal Themes of Bose-Einstein Condensation

Author: Nick P. Proukakis

Publisher: Cambridge University Press

Published: 2017-04-27

Total Pages: 663

ISBN-13: 1107085691

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Covering general theoretical concepts and the research to date, this book demonstrates that Bose-Einstein condensation is a truly universal phenomenon.


Book Synopsis Universal Themes of Bose-Einstein Condensation by : Nick P. Proukakis

Download or read book Universal Themes of Bose-Einstein Condensation written by Nick P. Proukakis and published by Cambridge University Press. This book was released on 2017-04-27 with total page 663 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covering general theoretical concepts and the research to date, this book demonstrates that Bose-Einstein condensation is a truly universal phenomenon.

Quantum Gases

Quantum Gases

Author: Nick Proukakis

Publisher: World Scientific

Published: 2013-02-21

Total Pages: 580

ISBN-13: 1908979704

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The 1995 observation of Bose–Einstein condensation in dilute atomic vapours spawned the field of ultracold, degenerate quantum gases. Unprecedented developments in experimental design and precision control have led to quantum gases becoming the preferred playground for designer quantum many-body systems. This self-contained volume provides a broad overview of the principal theoretical techniques applied to non-equilibrium and finite temperature quantum gases. Covering Bose–Einstein condensates, degenerate Fermi gases, and the more recently realised exciton–polariton condensates, it fills a gap by linking between different methods with origins in condensed matter physics, quantum field theory, quantum optics, atomic physics, and statistical mechanics. Thematically organised chapters on different methodologies, contributed by key researchers using a unified notation, provide the first integrated view of the relative merits of individual approaches, aided by pertinent introductory chapters and the guidance of editorial notes. Both graduate students and established researchers wishing to understand the state of the art will greatly benefit from this comprehensive and up-to-date review of non-equilibrium and finite temperature techniques in the exciting and expanding field of quantum gases and liquids. Contents:Introductory Material:Quantum Gases: The BackgroundQuantum Gases: Experimental ConsiderationsQuantum Gases: Background Key Theoretical NotionsUltracold Bosonic Gases: Theoretical Modelling:Kinetic and Many-Body ApproachesClassical-Field, Stochastic and Field-Theoretic ApproachesComparison of Common TheoriesOverview of Related Quantum-Degenerate Systems:Nearly Integrable One-Dimensional SystemsOptical Lattice GeometriesLiquid HeliumDegenerate Fermi GasesExciton/Polariton Condensation Readership: Aimed at graduate level students and for researchers. Keywords:Quantum Gas;Bose–Einstein;Condensate;Mean Field;Classical Field;Quantum Dynamics;Cold Atom;Ultracold Atom;Superfluid;Non-Equilibrium;Kinetic Theory;Field Theory;Quantum Fluid;Quantum Liquid;Degenerate Gas;Quantum Statistics;Number-Conserving;Symmetry-Breaking;Finite Temperature;Fluctuations;Stochastic;Gross–Pitaevskii;Bogoliubov;Many Body;Phase-Space Methods;Low-Dimensional;Optical Lattice;Bose;Fermi;Exciton;Polariton;ThermalizationKey Features:This book provides a unique and editorially linked, impartial unified presentation of the leading theoretical models for quantum gases far from equilibrium, and at finite temperaturesIn addition to focusing on bosonic gases, this book also makes connections to related quantum gases and fluids, such as fermionic gases, atoms in optical lattices, as well as exciton and polariton condensatesIntroductory chapters make this book an essential, accessible resource to both graduate students and early researchers as well as established scientists, with individual chapters written and edited by prominent researchers in the fieldReviews:“This book should be the first reference point for learning about various theoretical approaches to describing quantum gases. The editors and contributors have created a unique book with well-written articles, meaningful comparisons of various approximation schemes, a uniform notation and more than one thousand references. In addition, the book features introductory chapters and up-to-date review articles of experimental methods and current frontiers. The completeness and depth of the presentation are impressive.”Wolfgang Ketterle, MIT-Harvard Center for Ultracold Atoms & Nobel Laureate


Book Synopsis Quantum Gases by : Nick Proukakis

Download or read book Quantum Gases written by Nick Proukakis and published by World Scientific. This book was released on 2013-02-21 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 1995 observation of Bose–Einstein condensation in dilute atomic vapours spawned the field of ultracold, degenerate quantum gases. Unprecedented developments in experimental design and precision control have led to quantum gases becoming the preferred playground for designer quantum many-body systems. This self-contained volume provides a broad overview of the principal theoretical techniques applied to non-equilibrium and finite temperature quantum gases. Covering Bose–Einstein condensates, degenerate Fermi gases, and the more recently realised exciton–polariton condensates, it fills a gap by linking between different methods with origins in condensed matter physics, quantum field theory, quantum optics, atomic physics, and statistical mechanics. Thematically organised chapters on different methodologies, contributed by key researchers using a unified notation, provide the first integrated view of the relative merits of individual approaches, aided by pertinent introductory chapters and the guidance of editorial notes. Both graduate students and established researchers wishing to understand the state of the art will greatly benefit from this comprehensive and up-to-date review of non-equilibrium and finite temperature techniques in the exciting and expanding field of quantum gases and liquids. Contents:Introductory Material:Quantum Gases: The BackgroundQuantum Gases: Experimental ConsiderationsQuantum Gases: Background Key Theoretical NotionsUltracold Bosonic Gases: Theoretical Modelling:Kinetic and Many-Body ApproachesClassical-Field, Stochastic and Field-Theoretic ApproachesComparison of Common TheoriesOverview of Related Quantum-Degenerate Systems:Nearly Integrable One-Dimensional SystemsOptical Lattice GeometriesLiquid HeliumDegenerate Fermi GasesExciton/Polariton Condensation Readership: Aimed at graduate level students and for researchers. Keywords:Quantum Gas;Bose–Einstein;Condensate;Mean Field;Classical Field;Quantum Dynamics;Cold Atom;Ultracold Atom;Superfluid;Non-Equilibrium;Kinetic Theory;Field Theory;Quantum Fluid;Quantum Liquid;Degenerate Gas;Quantum Statistics;Number-Conserving;Symmetry-Breaking;Finite Temperature;Fluctuations;Stochastic;Gross–Pitaevskii;Bogoliubov;Many Body;Phase-Space Methods;Low-Dimensional;Optical Lattice;Bose;Fermi;Exciton;Polariton;ThermalizationKey Features:This book provides a unique and editorially linked, impartial unified presentation of the leading theoretical models for quantum gases far from equilibrium, and at finite temperaturesIn addition to focusing on bosonic gases, this book also makes connections to related quantum gases and fluids, such as fermionic gases, atoms in optical lattices, as well as exciton and polariton condensatesIntroductory chapters make this book an essential, accessible resource to both graduate students and early researchers as well as established scientists, with individual chapters written and edited by prominent researchers in the fieldReviews:“This book should be the first reference point for learning about various theoretical approaches to describing quantum gases. The editors and contributors have created a unique book with well-written articles, meaningful comparisons of various approximation schemes, a uniform notation and more than one thousand references. In addition, the book features introductory chapters and up-to-date review articles of experimental methods and current frontiers. The completeness and depth of the presentation are impressive.”Wolfgang Ketterle, MIT-Harvard Center for Ultracold Atoms & Nobel Laureate

Non-equilibrium Dynamics of One-Dimensional Bose Gases

Non-equilibrium Dynamics of One-Dimensional Bose Gases

Author: Tim Langen

Publisher:

Published: 2015

Total Pages:

ISBN-13: 9783319185651

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This work presents a series of experiments with ultracold one-dimensional Bose gases, which establish said gases as an ideal model system for exploring a wide range of non-equilibrium phenomena. With the help of newly developed tools, like full distributions functions and phase correlation functions, the book reveals the emergence of thermal-like transient states, the light-cone-like emergence of thermal correlations and the observation of generalized thermodynamic ensembles. This points to a natural emergence of classical statistical properties from the microscopic unitary quantum evolution, and lays the groundwork for a universal framework of non-equilibrium physics. The thesis investigates a central question that is highly contested in quantum physics: how and to which extent does an isolated quantum many-body system relax? This question arises in many diverse areas of physics, and many of the open problems appear at vastly different energy, time and length scales, ranging from high-energy physics and cosmology to condensed matter and quantum information. A key challenge in attempting to answer this question is the scarcity of quantum many-body systems that are both well isolated from the environment and accessible for experimental study.


Book Synopsis Non-equilibrium Dynamics of One-Dimensional Bose Gases by : Tim Langen

Download or read book Non-equilibrium Dynamics of One-Dimensional Bose Gases written by Tim Langen and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This work presents a series of experiments with ultracold one-dimensional Bose gases, which establish said gases as an ideal model system for exploring a wide range of non-equilibrium phenomena. With the help of newly developed tools, like full distributions functions and phase correlation functions, the book reveals the emergence of thermal-like transient states, the light-cone-like emergence of thermal correlations and the observation of generalized thermodynamic ensembles. This points to a natural emergence of classical statistical properties from the microscopic unitary quantum evolution, and lays the groundwork for a universal framework of non-equilibrium physics. The thesis investigates a central question that is highly contested in quantum physics: how and to which extent does an isolated quantum many-body system relax? This question arises in many diverse areas of physics, and many of the open problems appear at vastly different energy, time and length scales, ranging from high-energy physics and cosmology to condensed matter and quantum information. A key challenge in attempting to answer this question is the scarcity of quantum many-body systems that are both well isolated from the environment and accessible for experimental study.

Interferometry with Interacting Bose-Einstein Condensates in a Double-Well Potential

Interferometry with Interacting Bose-Einstein Condensates in a Double-Well Potential

Author: Tarik Berrada

Publisher: Springer

Published: 2015-12-17

Total Pages: 229

ISBN-13: 3319272330

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This thesis demonstrates a full Mach–Zehnder interferometer with interacting Bose–Einstein condensates confined on an atom chip. It relies on the coherent manipulation of atoms trapped in a magnetic double-well potential, for which the author developed a novel type of beam splitter. Particle-wave duality enables the construction of interferometers for matter waves, which complement optical interferometers in precision measurement devices, both for technological applications and fundamental tests. This requires the development of atom-optics analogues to beam splitters, phase shifters and recombiners. Particle interactions in the Bose–Einstein condensate lead to a nonlinearity, absent in photon optics. This is exploited to generate a non-classical state with reduced atom-number fluctuations inside the interferometer. This state is then used to study the interaction-induced dephasing of the quantum superposition. The resulting coherence times are found to be a factor of three longer than expected for coherent states, highlighting the potential of entanglement as a resource for quantum-enhanced metrology.


Book Synopsis Interferometry with Interacting Bose-Einstein Condensates in a Double-Well Potential by : Tarik Berrada

Download or read book Interferometry with Interacting Bose-Einstein Condensates in a Double-Well Potential written by Tarik Berrada and published by Springer. This book was released on 2015-12-17 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis demonstrates a full Mach–Zehnder interferometer with interacting Bose–Einstein condensates confined on an atom chip. It relies on the coherent manipulation of atoms trapped in a magnetic double-well potential, for which the author developed a novel type of beam splitter. Particle-wave duality enables the construction of interferometers for matter waves, which complement optical interferometers in precision measurement devices, both for technological applications and fundamental tests. This requires the development of atom-optics analogues to beam splitters, phase shifters and recombiners. Particle interactions in the Bose–Einstein condensate lead to a nonlinearity, absent in photon optics. This is exploited to generate a non-classical state with reduced atom-number fluctuations inside the interferometer. This state is then used to study the interaction-induced dephasing of the quantum superposition. The resulting coherence times are found to be a factor of three longer than expected for coherent states, highlighting the potential of entanglement as a resource for quantum-enhanced metrology.

Novel Superfluids

Novel Superfluids

Author: Karl-Heinz Bennemann

Publisher: Oxford University Press

Published: 2013-02-28

Total Pages: 641

ISBN-13: 0199585911

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This book reports on the latest developments in the field of Superfluidity, one of the most fundamental, interesting, and important problems in physics, with applications ranging from metals, helium liquids, photons in cavities, excitons in semiconductors, to the interior of neutron stars and the present state of the Universe as a whole.


Book Synopsis Novel Superfluids by : Karl-Heinz Bennemann

Download or read book Novel Superfluids written by Karl-Heinz Bennemann and published by Oxford University Press. This book was released on 2013-02-28 with total page 641 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reports on the latest developments in the field of Superfluidity, one of the most fundamental, interesting, and important problems in physics, with applications ranging from metals, helium liquids, photons in cavities, excitons in semiconductors, to the interior of neutron stars and the present state of the Universe as a whole.

Nature

Nature

Author: Sir Norman Lockyer

Publisher:

Published: 2007

Total Pages: 1692

ISBN-13:

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Book Synopsis Nature by : Sir Norman Lockyer

Download or read book Nature written by Sir Norman Lockyer and published by . This book was released on 2007 with total page 1692 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Probing Non-equilibrium Dynamics in Two-dimensional Quantum Gases

Probing Non-equilibrium Dynamics in Two-dimensional Quantum Gases

Author: Cheng-An Chen

Publisher:

Published: 2022

Total Pages: 0

ISBN-13: 9788303113351

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This thesis explores the physics of non-equilibrium quantum dynamics in homogeneous two-dimensional (2D) quantum gases. Ultracold quantum gases driven out of equilibrium have been prominent platforms for studying quantum many-body physics. However, probing non-equilibrium dynamics in conventionally trapped, inhomogeneous atomic quantum gases has been a challenging task because coexisting mass transport and spreading of quantum correlations often complicate experimental analyses. In this work, the author solves this technical hurdle by producing ultracold cesium atoms in a quasi-2D optical box potential. The exquisite optical trap allows one to remove density inhomogeneity in a degenerate quantum gas and control its dimensionality. The author also details the development of a high-resolution, in situ imaging technique to monitor the evolution of collective excitations and quantum transport down to atomic shot-noise, and at the length scale of elementary collective excitations. Meanwhile, tunable Feshbach resonances in ultracold cesium atoms permit precise and dynamical control of interactions with high temporal and even spatial resolutions. By employing these state-of-the-art techniques, the author performed interaction quenches to control the generation and evolution of quasiparticles in quantum gases, presenting the first direct measurement of quantum entanglement between interaction quench generated quasiparticle pairs in an atomic superfluid. Quenching to attractive interactions, this work shows stimulated emission of quasiparticles, leading to amplified density waves and fragmentation, forming 2D matter-wave Townes solitons that were previously considered impossible to form in equilibrium due to their instability. This thesis unveils a set of scale-invariant and universal quench dynamics and provides unprecedented tools to explore quantum entanglement transport in a homogenous quantum gas.


Book Synopsis Probing Non-equilibrium Dynamics in Two-dimensional Quantum Gases by : Cheng-An Chen

Download or read book Probing Non-equilibrium Dynamics in Two-dimensional Quantum Gases written by Cheng-An Chen and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis explores the physics of non-equilibrium quantum dynamics in homogeneous two-dimensional (2D) quantum gases. Ultracold quantum gases driven out of equilibrium have been prominent platforms for studying quantum many-body physics. However, probing non-equilibrium dynamics in conventionally trapped, inhomogeneous atomic quantum gases has been a challenging task because coexisting mass transport and spreading of quantum correlations often complicate experimental analyses. In this work, the author solves this technical hurdle by producing ultracold cesium atoms in a quasi-2D optical box potential. The exquisite optical trap allows one to remove density inhomogeneity in a degenerate quantum gas and control its dimensionality. The author also details the development of a high-resolution, in situ imaging technique to monitor the evolution of collective excitations and quantum transport down to atomic shot-noise, and at the length scale of elementary collective excitations. Meanwhile, tunable Feshbach resonances in ultracold cesium atoms permit precise and dynamical control of interactions with high temporal and even spatial resolutions. By employing these state-of-the-art techniques, the author performed interaction quenches to control the generation and evolution of quasiparticles in quantum gases, presenting the first direct measurement of quantum entanglement between interaction quench generated quasiparticle pairs in an atomic superfluid. Quenching to attractive interactions, this work shows stimulated emission of quasiparticles, leading to amplified density waves and fragmentation, forming 2D matter-wave Townes solitons that were previously considered impossible to form in equilibrium due to their instability. This thesis unveils a set of scale-invariant and universal quench dynamics and provides unprecedented tools to explore quantum entanglement transport in a homogenous quantum gas.

Quantum Field Theory of Non-equilibrium States

Quantum Field Theory of Non-equilibrium States

Author: Jørgen Rammer

Publisher: Cambridge University Press

Published: 2011-03-03

Total Pages: 0

ISBN-13: 9780521188005

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Quantum field theory is the application of quantum mechanics to systems with infinitely many degrees of freedom. This 2007 textbook presents quantum field theoretical applications to systems out of equilibrium. It introduces the real-time approach to non-equilibrium statistical mechanics and the quantum field theory of non-equilibrium states in general. It offers two ways of learning how to study non-equilibrium states of many-body systems: the mathematical canonical way and an easy intuitive way using Feynman diagrams. The latter provides an easy introduction to the powerful functional methods of field theory, and the use of Feynman diagrams to study classical stochastic dynamics is considered in detail. The developed real-time technique is applied to study numerous phenomena in many-body systems. Complete with numerous exercises to aid self-study, this textbook is suitable for graduate students in statistical mechanics and condensed matter physics.


Book Synopsis Quantum Field Theory of Non-equilibrium States by : Jørgen Rammer

Download or read book Quantum Field Theory of Non-equilibrium States written by Jørgen Rammer and published by Cambridge University Press. This book was released on 2011-03-03 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum field theory is the application of quantum mechanics to systems with infinitely many degrees of freedom. This 2007 textbook presents quantum field theoretical applications to systems out of equilibrium. It introduces the real-time approach to non-equilibrium statistical mechanics and the quantum field theory of non-equilibrium states in general. It offers two ways of learning how to study non-equilibrium states of many-body systems: the mathematical canonical way and an easy intuitive way using Feynman diagrams. The latter provides an easy introduction to the powerful functional methods of field theory, and the use of Feynman diagrams to study classical stochastic dynamics is considered in detail. The developed real-time technique is applied to study numerous phenomena in many-body systems. Complete with numerous exercises to aid self-study, this textbook is suitable for graduate students in statistical mechanics and condensed matter physics.