Quantum Mechanics

Quantum Mechanics

The framework to do physics that has replaced classical physics as the correct description of fundamental theory.

Classical Physics

An approximation that is conceptually very different from quantum mechanics.

Quantum Electrodynamics

Quantum mechanics applied to electromagnetism.

Quantum Chromodynamics

Quantum mechanics applied to the strong interaction.

Quantum Optics

Quantum mechanics applied to photons.

Quantum Gravity

The application of quantum mechanics to gravitation.

Linearity

A fundamental aspect of quantum mechanics where solutions can be added together without affecting each other.

Dynamical Variables

Variables in a theory connected with observation, the values of which can be compared to experimental results.

Maxwell's Theory of Electromagnetism

A linear theory that states two plane wave solutions can be added together to form a new solution.

Superposition

The principle that multiple waves can propagate simultaneously without interfering with each other.

Complex Numbers

Numbers that have a real part and an imaginary part, necessary for describing quantum mechanics.

Determinism in Quantum Mechanics

The concept in quantum mechanics that certain dynamic variables can have predicted values.

Entanglement

A phenomenon in quantum mechanics where particles become interconnected and the state of one cannot be described independently of the state of another.

Linear Equation

An equation of the form L(u) = 0, where L is a linear operator acting on an unknown u.

Linear Operator

An operator that satisfies properties allowing it to act linearly on unknowns.

Charge Density

The amount of charge per unit volume.

Current Density

Charge per unit area per unit time.

Equations of Motion (EOM)

Mathematical equations that describe the behavior of dynamical variables in a physical system.

Alpha (α)

A constant multiplier that can be applied to solutions while preserving their validity in linear systems.

Solution Space

A collection of all possible solutions to a given set of equations.

First Law of Thermodynamics

Energy cannot be created or destroyed, only transformed from one form to another.

Second Law of Thermodynamics

The total entropy of an isolated system can never decrease over time; it can only increase or remain constant.

Third Law of Thermodynamics

As the temperature of a system approaches absolute zero, the entropy of the system approaches a constant minimum.

Thermodynamic System

A portion of the universe chosen for analysis, which can exchange energy and matter with its surroundings.

Isolated System

A system that cannot exchange energy or matter with its surroundings.

Closed System

A system that can exchange energy but not matter with its surroundings.

Open System

A system that can exchange both energy and matter with its surroundings.

Heat Transfer

The movement of thermal energy from one object to another due to a temperature difference.

Entropy

A measure of the disorder or randomness of a system, indicating the amount of energy not available for doing work.