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Physics

The study subject of physics is the fundamental understanding of matter, energy, and the interactions between them.

At the most fundamental levels physics is a theory of forces and fields.

Field Based Theories vs Particle Based Theories.

Index

Study Guide

What should we teach first? Should we teach the correct but unfamiliar law with its strange and difficult conceptual ideas, for example the theory of relativity, four-dimensional space-time, and so on? Or should we first teach the simple “constant-mass” law, which is only approximate, but does not involve such difficult ideas? The first is more exciting, more wonderful, and more fun, but the second is easier to get at first, and is a first step to a real understanding of the first idea. This point arises again and again in teaching physics. At different times we shall have to resolve it in different ways, but at each stage it is worth learning what is now known, how accurate it is, how it fits into everything else, and how it may be changed when we learn more. - Feynman.

Branches of Physics

Branch Focus Key Topics
Mechanics Motion of objects and the forces acting on them. Kinematics, dynamics, statics, fluid mechanics, rotational motion
Thermodynamics Heat, temperature, and energy transfer. Laws of thermodynamics, heat engines, entropy, phase transitions
Electromagnetism Electric and magnetic fields and their interactions. Maxwell’s equations, circuits, waves, optics, electromagnetic radiation
Optics Behavior and properties of light. Reflection, refraction, lenses, wave optics, quantum optics
Relativity Motion at high speeds and the effects of gravity on spacetime. Special relativity, general relativity, black holes, gravitational waves
Quantum Mechanics Behavior of particles at atomic and subatomic scales. Wave-particle duality, Schrödinger equation, quantum states, entanglement
Atomic and Nuclear Physics Structure and behavior of atoms and nuclei. Atomic models, radioactivity, nuclear reactions, particle physics
Condensed Matter Physics Properties of solids and liquids. Crystals, semiconductors, superconductors, magnetism, phase transitions
Particle Physics Fundamental particles and forces in the universe. Standard Model, quarks, leptons, Higgs boson, particle accelerators
Astrophysics and Cosmology The universe, its origins, and its large-scale structure. Big Bang, galaxies, stars, black holes, dark matter, dark energy
Surface Science Surface Science studies systems and phenomena occurring specifically at the surface or interface of materials, focusing on the physical and chemical properties that differ from the bulk material. It explores how surfaces interact with their environment, how they influence material behavior, and how surface phenomena impact various technologies.

Physical Systems

Here’s a comprehensive table summarizing the taxonomy of physical systems based on their scale, behavior, interactions, complexity, state of matter, dynamics, energy exchange, and field of study:

Category Subcategory Description Examples
By Scale Macroscopic Systems Systems at human scales, described by classical physics. Pendulums, springs, planets, fluids, engines
Microscopic Systems Systems at atomic or molecular scales, described by quantum mechanics. Atoms, molecules, electrons, photons
Cosmological Systems Systems at the scale of the universe, described by general relativity. Galaxies, black holes, the universe as a whole
By Behavior Mechanical Systems Systems involving motion and forces. Projectiles, rotating objects, vibrating strings
Thermodynamic Systems Systems involving heat, energy, and entropy. Heat engines, refrigerators, phase transitions
Electromagnetic Systems Systems involving electric and magnetic fields. Circuits, antennas, electromagnetic waves
Quantum Systems Systems exhibiting quantum behavior. Quantum particles, superconductors, quantum computers
By Interactions Closed Systems Systems that do not exchange matter with their surroundings (may exchange energy). Sealed container of gas, thermos flask
Open Systems Systems that exchange both matter and energy with their surroundings. Living organisms, ecosystems, chemical reactors
Isolated Systems Systems that do not exchange matter or energy with their surroundings. The universe (theoretically), idealized thermos flask
By Complexity Simple Systems Systems with few components and predictable behavior. Single pendulum, mass on a spring
Complex Systems Systems with many interacting components and emergent behavior. Weather systems, ecosystems, the human brain
By State of Matter Solid Systems Systems composed of solids. Crystals, metals, buildings
Liquid Systems Systems composed of liquids. Water in a pipe, oceans, blood flow
Gaseous Systems Systems composed of gases. Earth’s atmosphere, gas in a container
Plasma Systems Systems composed of ionized gases. Stars, neon lights, fusion reactors
By Dynamics Linear Systems Systems where the output is directly proportional to the input. Simple harmonic oscillators, linear circuits
Nonlinear Systems Systems where the output is not directly proportional to the input. Turbulent fluids, weather systems, double pendulums
By Energy Exchange Conservative Systems Systems where energy is conserved (no dissipation). Idealized pendulums, planetary orbits
Dissipative Systems Systems where energy is lost (e.g., due to friction or resistance). Real-world pendulums, electrical circuits with resistance
By Field of Study Astrophysical Systems Systems in space. Stars, galaxies, black holes
Geophysical Systems Systems related to Earth. Earth’s atmosphere, tectonic plates, oceans
Biological Systems Systems in living organisms. Cells, organs, ecosystems

Mechanics

Main Field Subfield Description
Classical Mechanics Kinematics Description of motion without regard to forces (position, velocity, acceleration)
Dynamics Motion under the influence of forces (Newton’s laws, energy, momentum)
Statics Equilibrium of systems with zero net force or moment
Rigid Body Mechanics Study of non-deformable bodies in motion and equilibrium
Particle Mechanics Dynamics of particles or point masses
Celestial Mechanics Study of motions of celestial bodies under gravity
Continuum Mechanics Study of materials modeled as continuous media (solids, fluids, multiphase systems)
Solid Mechanics Deformation, stress, and strain in solid materials
Fluid Mechanics Flow, pressure, and motion in liquids and gases
Incompressible Flow – Fluid flows with negligible density changes
Compressible Flow – Flows with significant density variations
Laminar Flow – Smooth, layered fluid motion
Turbulent Flow – Chaotic, irregular fluid motion
Multiphase Flow – Interaction of multiple fluid phases (liquid-gas, liquid-solid, etc.)
Boundary Layer Theory – Thin viscous regions near surfaces
Hydrodynamics – Study of fluid motion ignoring compressibility and thermal effects
Aerodynamics – Air flow around bodies such as aircraft and vehicles
Magnetohydrodynamics (MHD) – Conducting fluids influenced by magnetic fields
Geophysical Fluid Dynamics – Large scale flows in oceans, atmosphere, and planetary interiors
Biofluid Mechanics – Fluid flow in biological systems (e.g., blood circulation)
Fracture Mechanics Initiation and propagation of cracks in solids
Elasticity Reversible deformations in materials under stress
Plasticity Permanent deformations beyond yield point
Viscoelasticity Time-dependent behavior with elastic and viscous characteristics
Damage Mechanics Progressive material deterioration
Rheology Study of flow and deformation of complex (non-Newtonian) fluids
Peridynamics Modeling discontinuities naturally, useful for fracture mechanics
Analytical Mechanics Lagrangian Mechanics Motion via principle of least action using generalized coordinates
Hamiltonian Mechanics Reformulation using energy functions and phase space
Rational Mechanics Axiomatic, deductive mechanics based on continuum assumptions
Hamilton–Jacobi equation
Gibbs–Appell equation of motion
Routhian mechanics
Liouville's formulation.
Udwadia–Kalaba formulation
Computational Mechanics Finite Element Method (FEM) Numerical solution of boundary value problems in solids and fluids
Computational Fluid Dynamics (CFD) Numerical simulation of fluid flows using discretization
Meshless & Multiscale Methods Numerical methods for complex domains and phenomena
Statistical Mechanics Equilibrium Statistical Mechanics Macroscopic properties derived from microscopic behavior
Non-equilibrium Statistical Mechanics Systems evolving toward equilibrium; transport phenomena
Thermodynamic Ensembles Canonical, microcanonical, and grand canonical ensembles
Multibody Mechanics Articulated Systems Systems of rigid or flexible bodies connected by joints
Biomechanics — Mechanics applied to biological systems (tissues, motion, physiology)
Geomechanics — Behavior of geological materials (soils, rocks) under load
Aeroelasticity — Interaction of aerodynamic forces and structural flexibility
Acoustics & Vibrations Wave Mechanics Mechanical wave propagation in solids and fluids
Vibrations Oscillatory motion of systems including resonance and damping
Relativistic Mechanics — Mechanics incorporating special relativity (high-speed systems)
Quantum Mechanics — Fundamental theory for particles at atomic/subatomic scales (non-classical)
Nonlinear Mechanics — Systems with nonlinear responses including chaos and bifurcation theory
Experimental Mechanics — Measurement and validation of mechanical behavior (e.g., strain gauges, interferometry)

Relativity

Main Field Subfield Description
Relativity Special Relativity Theory describing physics in inertial frames at constant velocities, introducing time dilation, length contraction, and mass-energy equivalence (E=mc²).
General Relativity Theory of gravitation modeling gravity as curvature of spacetime caused by mass-energy; explains phenomena like black holes, gravitational waves, and cosmology.
Relativistic Mechanics Mechanics of particles and fields consistent with special relativity, including relativistic dynamics and electromagnetism.
Relativistic Quantum Mechanics Extension of quantum mechanics consistent with special relativity (e.g., Dirac equation, Klein-Gordon equation).
Quantum Field Theory in Curved Spacetime Study of quantum fields in a curved spacetime background, bridging quantum theory and general relativity.
Experimental Relativity Tests and observations verifying relativity predictions, including time dilation in particle accelerators and gravitational wave detection.
Applications in Astrophysics and Cosmology Uses relativity to understand black holes, neutron stars, the expanding universe, and cosmic background radiation.

Optics

Main Field Subfield Description
Optics Geometrical Optics Describes light propagation in terms of rays; includes reflection, refraction, lenses, and mirrors.
Physical Optics Studies wave nature of light, including interference, diffraction, polarization, and coherence.
Quantum Optics Examines light as quantized photons; studies quantum states of light, entanglement, and quantum information.
Nonlinear Optics Studies light-matter interactions where response depends nonlinearly on the light intensity (e.g., frequency doubling).
Laser Optics Focuses on the generation, properties, and applications of lasers.
Fiber Optics Transmission of light through optical fibers for communication and sensing.
Optical Materials Studies materials’ interaction with light, including absorption, emission, and refractive properties.
Optoelectronics Combines optics and electronics, including devices like photodetectors and LEDs.
Imaging and Vision Optics Optical systems for image formation, microscopy, and human vision.
Computational Optics Use of algorithms and simulations to model optical systems and processes.

Quantum Mechanics

Quantum physics is a branch of physics that explores the behavior of matter and energy at the smallest scales, describing phenomena that cannot be explained by classical physics, involving discrete energy levels, wave-particle duality, superposition, and entanglement.

Main Field Subfield Description
Quantum Mechanics Non-Relativistic Quantum Mechanics Standard quantum theory for low-energy systems; Schrödinger equation, wavefunctions, operators
Quantum Field Theory (QFT) Quantum mechanics combined with special relativity; fields as fundamental entities; particle creation/annihilation
Quantum Statistical Mechanics Application of quantum mechanics to ensembles and thermodynamic systems; density matrices, quantum ensembles
Quantum Information Theory Study of quantum computation, quantum communication, entanglement, quantum cryptography
Quantum Optics Interaction of light (photons) with matter at the quantum level; lasers, photon statistics
Many-Body Quantum Mechanics Quantum mechanics of systems with many interacting particles; condensed matter, nuclear physics
Relativistic Quantum Mechanics Quantum mechanics incorporating relativity before full QFT (e.g., Dirac equation, Klein-Gordon)
Quantum Foundations Conceptual and philosophical aspects; measurement problem, interpretations of quantum mechanics
Quantum Chemistry Application of quantum mechanics to molecular structure, reactions, and properties
Quantum Control Manipulation of quantum systems for desired dynamics, e.g., in quantum computing and sensing

Thermodynamics

Note: Getting information from this name is a mistake; the field has broaden so much.

"Thermodynamics" is an archaic name that reflects the field's origins in the study of heat. However, modern thermodynamics encompasses a far broader range of phenomena, including general energy transformations and the principles of entropy. A more accurate name today might be “Energetics and Entropy Theory.”

Thermodynamics is the branch of physics that studies the macroscopic behavior of systems based on the statistical averaging of microscopic degrees of freedom, governed by conservation laws and entropy considerations. It formalizes the relationships among thermodynamic state variables (e.g., energy \(E\), entropy \(S\), volume \(V\), pressure \(P\), temperature \(T\), particle number \(N\)) under various constraints and transformations, using a mathematically consistent axiomatic framework.

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Main Field Subfield Description
Thermodynamics Classical (Macroscopic) Thermodynamics Study of bulk systems, energy exchanges, work, heat, and thermodynamic laws without microscopic detail.
Statistical Thermodynamics (Statistical Mechanics) Explains thermodynamic properties from microscopic particle behavior and probability/statistics.
Chemical Thermodynamics Thermodynamics of chemical reactions, phase equilibria, and reaction spontaneity
Equilibrium Thermodynamics Study of systems in thermodynamic equilibrium where macroscopic properties are time-invariant
Non-Equilibrium Thermodynamics Analysis of systems out of equilibrium, including transport phenomena (heat, mass, momentum) and irreversible processes
Thermochemistry Energy changes associated with chemical reactions and phase changes
Thermomechanics (Thermophysical Mechanics) Coupling of mechanical behavior with thermal effects such as thermal expansion, thermoelasticity, and heat conduction
Engineering Thermodynamics Application of thermodynamics principles to engineering systems like engines, turbines, refrigeration
Biological Thermodynamics Thermodynamic principles applied to biological systems and processes
Statistical Thermodynamics of Quantum Systems Quantum statistical mechanics describing thermodynamics at quantum scales

Condensed Matter Physics

Subfield Focus Area Examples / Key Concepts
Crystallography Study of atomic structure and symmetry in solids Bravais lattices, space groups, X-ray diffraction
Electronic Structure Behavior of electrons in solids Band theory, density functional theory (DFT), Fermi surfaces
Solid State Physics Classical core of condensed matter physics Semiconductors, insulators, conductors, magnetism
Magnetism Magnetic ordering and spin interactions Ferromagnetism, antiferromagnetism, spin waves, magnonics
Superconductivity Zero-resistance states, Meissner effect BCS theory, high-Tc superconductors, Josephson junctions
Semiconductor Physics Charge transport in semiconducting materials p-n junctions, transistors, excitons
Optoelectronics / Photonics Light-matter interaction in solids LEDs, laser materials, quantum dots
Strongly Correlated Systems Materials where interactions dominate single-particle behavior Mott insulators, heavy fermions, Hubbard model
Quantum Hall Effects Topological phases under strong magnetic fields Integer and fractional QHE, Chern numbers
Topological Matter Phases protected by topology Topological insulators, Weyl semimetals, edge states
Low-Dimensional Systems Properties of 2D/1D/0D materials Graphene, nanotubes, quantum dots, monolayer TMDs
Spintronics Use of spin for information processing Spin valves, spin-Hall effect, MRAM
Quantum Materials Engineered or natural systems with quantum coherence Kitaev materials, quantum spin liquids, twisted bilayer graphene
Disordered Systems / Glasses Non-crystalline states, structural randomness Amorphous solids, spin glasses, localization
Soft Condensed Matter Systems with weak interactions and large fluctuations Liquid crystals, polymers, colloids, biological materials
Mesoscopic Physics Intermediate scale between quantum and classical regimes Quantum dots, Coulomb blockade, phase coherence
Nanostructures Physics at the nanoscale Quantum confinement, surface effects, nano-electronics
Surface and Interface Physics Phenomena at material boundaries Thin films, heterostructures, 2D electron gases
Nonequilibrium Systems Systems out of thermodynamic equilibrium Transport phenomena, driven systems, pattern formation
Ultrafast Dynamics Time-resolved phenomena on femto/picosecond scales Pump-probe spectroscopy, phonon dynamics
Quantum Criticality Behavior near zero-temperature phase transitions Scaling laws, non-Fermi liquids, quantum fluctuations
Emergent Phenomena Collective behaviors not evident from microscopic laws Quasiparticles, collective modes, fractionalization
Computational Condensed Matter Simulation and modeling of condensed systems DFT, Monte Carlo, molecular dynamics, tight-binding
Experimental Techniques Tools for characterizing materials ARPES, STM, neutron scattering, TEM, SQUID
Surface Science Surface Science studies systems and phenomena occurring specifically at the surface or interface of materials, focusing on the physical and chemical properties that differ from the bulk material. It explores how surfaces interact with their environment, how they influence material behavior, and how surface phenomena impact various technologies.

Statistical Physics

Subfield Systems Studied Core Concepts Methods / Tools
Equilibrium Statistical Mechanics Gases, solids, liquids at equilibrium Microstates, entropy, partition function, ensembles (microcanonical, canonical, grand canonical) Ensemble theory, thermodynamic limit, analytical calculations
Non-equilibrium Statistical Mechanics Systems far from equilibrium (e.g. heat flow, diffusion, driven systems) Fluctuations, entropy production, relaxation, transport coefficients Master equations, Langevin and Fokker–Planck equations, linear response theory
Critical Phenomena & Phase Transitions Magnetic systems, fluids, superconductors Order parameter, symmetry breaking, scaling laws, universality, renormalization Renormalization group, scaling theory, Monte Carlo simulations
Quantum Statistical Mechanics Quantum gases, condensed matter systems Bose-Einstein statistics, Fermi-Dirac statistics, quantum entanglement Density matrix formalism, second quantization, path integrals
Information-Theoretic Statistical Mechanics Abstract systems, coding, computation models Entropy, mutual information, complexity measures Shannon entropy, maximum entropy principle, inference methods
Stochastic Processes & Fluctuation Theory Brownian motion, molecular noise, financial systems Random walks, noise, correlation functions, fluctuation–dissipation theorem Stochastic differential equations, Langevin dynamics
Computational Statistical Physics Many-body systems, disordered systems Numerical estimation of statistical quantities, finite-size scaling Monte Carlo, Molecular Dynamics, Metropolis algorithm
Statistical Field Theory Continuous systems, critical systems Field variables, correlation functions, path integrals, effective actions Functional integrals, diagrammatic methods, RG methods
Disordered and Complex Systems Glasses, spin glasses, neural networks Frustration, replica symmetry breaking, complexity landscapes Replica trick, mean-field theory, message passing
Thermodynamics (as statistical limit) Macroscopic systems Laws of thermodynamics as emergent from microstates Thermodynamic identities, Legendre transforms

Theoretical Physics

Theoretical physics is the branch of physics that develops mathematical models, conceptual frameworks, and abstract principles to explain, predict, and unify natural phenomena.

It seeks to formulate laws of nature in a rigorous, often mathematical form, and to derive consequences that can be compared with experimental or observational data.

Category Branch Description
Classical Theoretical Physics Mechanics (Newtonian, Lagrangian, Hamiltonian) Motion of particles and rigid bodies
Classical Field Theory (Electromagnetism, Fluid dynamics, Elasticity, Gravitation) Fields as continuous systems, differential equations
Thermodynamics & Statistical Mechanics (classical) Heat, energy, macroscopic laws, ensembles
Relativistic Theories Special Relativity Space-time, Lorentz invariance, relativistic dynamics
General Relativity Gravity as spacetime curvature, cosmology
Quantum Theories Quantum Mechanics Microscopic systems, uncertainty, wave–particle duality
Quantum Field Theory (QFT) Quantum fields, particle physics, Standard Model
Quantum Many-Body Theory Condensed matter, superconductivity, correlated systems
Quantum Gravity (speculative) String theory, loop quantum gravity, unification attempts
Statistical & Mathematical Physics Statistical Mechanics (classical & quantum) Microscopic origins of thermodynamics, phase transitions
Mathematical Physics Rigorous mathematical structures of physics
Nonlinear Dynamics & Chaos Complex dynamical systems, turbulence, attractors
High-Energy & Fundamental Theories Particle Physics Theory Standard Model, gauge theories
Beyond Standard Model (BSM) Supersymmetry, GUTs, extra dimensions
Cosmology & Astroparticle Theory Inflation, dark matter/energy, early universe
Condensed Matter & Emergent Theories Solid-State Theory Electronic structure, magnetism, phonons
Field-Theoretic Methods in Condensed Matter Effective field theories, topological phases
Statistical Field Theory Field methods applied to many-body systems
Modern & Interdisciplinary Frontiers Computational/Theoretical Modeling Simulation and numerical methods in theory
Information-Theoretic Physics Quantum information, entanglement, holography
Complex Systems & Network Theory Emergent and collective behavior in many-body and social systems

Ontology

Ontological Abstraction Definition Purpose Ontological Role Example
Particle Localized entity with well-defined properties Fundamental constituents of matter Discrete unit; simplest “thing” Electron, quark, photon
Field Continuous entity assigning values to space-time points Describes forces, energy, and waves Fundamental framework for interactions; sometimes more basic than particles Electromagnetic field ( \mathbf{E}, \mathbf{B} )
System Collection of particles, fields, or subsystems Study dynamics, thermodynamics, collective behavior Aggregated entity; higher-level organization Hydrogen atom, solar system, condensed matter system
Observable Measurable quantity of a system or field Connects theory to experiment Interface between model and empirical reality Position, momentum, energy, spin
Phenomenon An observed or measured occurrence Serves as the empirical target of theories Emergent / derivative; “what we see” Diffraction pattern, superconductivity
State Specification of a system’s configuration at a given time Predict evolution and responses Represents potentiality rather than a physical “thing” Quantum state (
Interaction / Force Mechanism by which entities influence each other Explain changes in motion or field configuration Fundamental relational abstraction Electromagnetic, gravitational interactions
Symmetry / Conservation Law Structural constraints governing invariances Guides dynamics, selection rules Abstract structural property, often fundamental Lorentz invariance, gauge symmetry

Classical Field Theory

Classical field theory is the branch of theoretical physics that describes physical systems in terms of continuous fields—quantities defined at every point in space and time.

It generalizes classical mechanics from discrete particles to distributed systems, providing the mathematical framework for phenomena such as electromagnetism (Maxwell’s equations), gravitation (general relativity), and continuum media (fluids, elasticity).

Its foundations are typically expressed through differential equations derived from variational principles (e.g., the Euler–Lagrange equations).

See more in Classical Field Theory (CFT).

Quantum Field Theory (QFT)

Quantum field theory is the branch of theoretical physics that combines quantum mechanics and special relativity to describe matter and interactions as excitations of underlying fields.

In QFT, particles are understood as quantized field excitations, and interactions are mediated by the exchange of such quanta.

QFT provides the foundation for the Standard Model of particle physics, unifying the electromagnetic, weak, and strong nuclear forces, and also serves as a framework in condensed matter physics for describing many-body systems and emergent phenomena.

Its formalism is based on Lagrangians, path integrals, and operator algebras, with central tools including renormalization and symmetry principles.

See more in Quantum Field Theory (QFT).

Lectures

References

  • Quantum Dynamics
  • Quantization (physics)
  • Superposition Principle
  • Bell's theorem
  • Carroll, S. M. (2022). Reality as a vector in Hilbert space. In Quantum mechanics and fundamentality: Naturalizing quantum theory between scientific realism and ontological indeterminacy (pp. 211–224). Springer.
  • https://en.wikipedia.org/wiki/Quantum_foundations
  • https://en.wikipedia.org/wiki/Interpretations_of_quantum_mechanics
  • Coecke, Bob, and Aleks Kissinger. “Picturing quantum processes: A first course on quantum theory and diagrammatic reasoning.” Diagrammatic Representation and Inference: 10th International Conference, Diagrams 2018, Edinburgh, UK, June 18-22, 2018, Proceedings 10. Springer International Publishing, 2018.
  • Max Planck (1900): "On the Law of Distribution of Energy in the Normal Spectrum." : Contribution: Introduced the concept of quantization of energy, proposing the idea of quantized energy levels or "quanta" to explain blackbody radiation.
  • Albert Einstein (1905): "On a Heuristic Viewpoint Concerning the Production and Transformation of Light." : Proposed the photoelectric effect, demonstrating that light can be described as discrete packets of energy (photons).
  • Louis de Broglie (1924): "Recherches sur la théorie des quanta" ("On the Theory of Quanta"): Introduced the idea of wave-particle duality, suggesting that particles, such as electrons, can exhibit both wave-like and particle-like behavior.
  • Werner Heisenberg (1925): "Über quantentheoretische Umdeutung kinematischer und mechanischer Beziehungen" ("Quantum-Theoretical Reinterpretation of Kinematic and Mechanical Relations") - Formulated matrix mechanics, a foundational approach to quantum mechanics focusing on matrices and observables.
  • Erwin Schrödinger (1926): "Quantisierung als Eigenwertproblem" ("Quantization as an Eigenvalue Problem") Contribution: Developed wave mechanics, an alternative formulation of quantum mechanics based on wave functions and partial differential equations.
  • Max Born, Werner Heisenberg, Pascual Jordan (1926): "Zur Quantenmechanik II" ("On Quantum Mechanics II") Contribution: Introduced the matrix formulation of quantum mechanics, known as matrix mechanics.
  • Paul Dirac (1927): "The Quantum Theory of the Emission and Absorption of Radiation." - Developed quantum field theory, which combines quantum mechanics with special relativity, and introduced the Dirac equation describing relativistic electrons.
  • Max Born (1928): "On Quantum Mechanics of Collisions." - Formulated Born's rule connects the wave function to the probability of finding a particle in a particular state.
  • John von Neumann (1932): "Mathematische Grundlagen der Quantenmechanik" ("Mathematical Foundations of Quantum Mechanics") - Provided a rigorous mathematical quantum mechanics formulation, incorporating matrix and wave mechanics into a unified framework.
  • Kindergarden quantum mechanics graduates …or how I learned to stop gluing LEGO together and love the ZX-calculus
  • Scott Aaronson | Quantum Computing: Dismantling the Hype | The Cartesian Cafe with Timothy Nguyen
  • https://en.wikipedia.org/wiki/Physics
  • https://en.wikipedia.org/wiki/Cosmology
  • https://en.wikipedia.org/wiki/Astronomy
  • https://en.wikipedia.org/wiki/Continuum_mechanics
  • Thermodynamics
    • https://en.wikipedia.org/wiki/Thermodynamic_system
    • Elements of classical and statistical thermodynamics
    • Münster A. Classical Thermodynamics 1970
    • Treatise on thermodynamics
    • https://en.wikipedia.org/wiki/List_of_textbooks_in_thermodynamics_and_statistical_mechanics
    • https://en.wikipedia.org/wiki/History_of_thermodynamics
    • Sadi Carnot - Reflections on the Motive Power of Fire
    • Rudolf Clausius
      • On the Moving Force of Heat
      • On the Mechanical Theory of Heat
    • William Thomson (Lord Kelvin) - On the Dynamical Theory of Heat
    • Josiah Willard Gibbs
      • A Method of Geometrical Representation of the Thermodynamic Properties of Substances by Means of Surfaces
      • On the Equilibrium of Heterogeneous Substances
    • Ludwig Boltzmann - On the Relationship between the Second Law of Thermodynamics and Probability Theory
    • Gilbert N. Lewis - A New Conception of Thermal Pressure and the Thermodynamics of Fluid Systems
    • Walther Nernst - The New Heat Theorem
    • Lars Onsager - Reciprocal Relations in Irreversible Processes
    • Ilya Prigogine - Étude Thermodynamique des Phénomènes Irréversibles
    • Herbert Callen - Thermodynamics and an Introduction to Thermostatistics
    • Elliot Montroll & George Uhlenbeck - Studies in Statistical Mechanics
    • David Chandler - Introduction to Modern Statistical Mechanics
  • https://en.wikipedia.org/wiki/Statics
  • https://en.wikipedia.org/wiki/Mechanics
  • https://en.wikipedia.org/wiki/Continuum_mechanics
  • https://en.wikipedia.org/wiki/Applied_mechanics
  • https://en.wikipedia.org/wiki/Mechanical_engineering
  • https://en.wikipedia.org/wiki/Fluid_dynamics
  • https://en.wikipedia.org/wiki/Dynamics
  • https://en.wikipedia.org/wiki/Branches_of_physics
  • https://en.wikipedia.org/wiki/Celestial_mechanics
  • https://en.wikipedia.org/wiki/Solar_System
  • https://en.wikipedia.org/wiki/Mathematical_formulation_of_quantum_mechanics
  • https://en.wikipedia.org/wiki/Mechanics
  • https://en.wikipedia.org/wiki/Classical_mechanics
  • https://en.wikipedia.org/wiki/Analytical_mechanics
  • https://en.wikipedia.org/wiki/Orbital_mechanics - Astrodynamics.