A Matrix Product State (MPS) is a mathematical representation commonly used in quantum physics and quantum computing to describe quantum many-body systems. It provides an efficient way to represent and manipulate states of quantum systems that may have an exponentially large dimension in the standard basis. ### Description An MPS is expressed as a product of matrices, which allows for the encoding of quantum states in a way that maintains a manageable computational complexity.
The mathematical formulation of quantum mechanics describes physical systems in terms of abstract mathematical structures and principles. The two primary formulations of quantum mechanics are the wave mechanics formulated by Schrödinger and the matrix mechanics developed by Heisenberg, which were later unified in the framework of quantum theory.
The electromagnetic field is fundamentally described by the framework of classical electromagnetic theory, particularly through Maxwell's equations. These equations encapsulate how electric and magnetic fields interact with each other and with charges.
The Magnus expansion is a mathematical technique used in the field of differential equations and quantum mechanics to solve time-dependent problems involving linear differential equations. Specifically, it is often applied to systems governed by operators that evolve in time, which is particularly relevant in quantum mechanics for the evolution of state vectors and operators. In essence, the Magnus expansion provides a way to express the time-evolution operator \( U(t) \), which describes how a state changes over time under the influence of a Hamiltonian or other operator.
A Lyapunov vector is a mathematical concept used in the study of dynamical systems, particularly in the context of stability analysis and the behavior of differential equations. Lyapunov vectors are related to Lyapunov exponents, which measure the rate of separation of infinitesimally close trajectories of a dynamical system. When analyzing the stability of a fixed point or equilibrium of a dynamical system, Lyapunov exponents help quantify the growth or decay rates of perturbations around that point.
The Lorentz transformation is a set of equations in the theory of special relativity that relate the space and time coordinates of two observers moving at constant velocity relative to each other. Named after the Dutch physicist Hendrik Lorentz, these transformations are essential for understanding how measurements of time and space change for observers in different inertial frames of reference, particularly when approaching the speed of light.
In the context of mathematics, particularly in the study of Lie algebras, an **extension** refers to a way of constructing a new Lie algebra from a given Lie algebra by adding extra structure.
The Legendre transformation is a mathematical operation used primarily in convex analysis and optimization, as well as in physics, particularly in thermodynamics and mechanics. It allows one to convert a function of one set of variables into a function of another set, changing the viewpoint on how the variables are related.
The Laplace transform is a powerful integral transform used in various fields of engineering, physics, and mathematics to analyze and solve differential equations and system dynamics. It converts a function of time, typically denoted as \( f(t) \), which is often defined for \( t \geq 0 \), into a function of a complex variable \( s \), denoted as \( F(s) \).
The Laguerre transform is a mathematical transform that is closely related to the concept of orthogonal polynomials, specifically the Laguerre polynomials. It is often used in various fields such as probability theory, signal processing, and applied mathematics due to its properties in representing functions and handling certain types of problems.
Lagrangian mechanics is a formulation of classical mechanics that uses the principle of least action to describe the motion of objects. Developed by the mathematician Joseph-Louis Lagrange in the 18th century, this approach reformulates Newtonian mechanics, providing a powerful and elegant framework for analyzing mechanical systems.
In the context of field theory and theoretical physics, the Lagrangian is a mathematical function that encapsulates the dynamics of a system. It is a central concept in the Lagrangian formulation of mechanics, which has been extended to fields in the context of quantum field theory and classical field theory.
Koopman–von Neumann classical mechanics is a formalism of classical mechanics that extends traditional Hamiltonian mechanics, providing a framework that emphasizes the use of functional spaces and operators rather than conventional state variables. This approach is rooted in the work of mathematicians and physicists, particularly B.O. Koopman and J. von Neumann, in the 1930s.
The Klein-Gordon equation is a relativistic wave equation for scalar particles, derived from both quantum mechanics and special relativity. It describes the dynamics of a scalar field, which represents a particle of spin-0 (such as a pion or any other fundamental scalar particle).
The term "Jordan map" can refer to different concepts depending on the context in which it is used. However, it is most commonly associated with the Jordan canonical form in linear algebra or the Jordan Curve Theorem in topology. 1. **Jordan Canonical Form**: In linear algebra, the Jordan form is a way of representing a linear operator (or matrix) in an almost diagonal form.
The Joos-Weinberg equation is a mathematical expression used in the context of quantum field theory, particularly in the study of particle physics. It is associated with the calculation of certain processes involving electroweak interactions. However, the term is less commonly referenced in the literature compared to other equations and theories in particle physics, such as the Dirac equation or the Standard Model equations.
The Infeld–Van der Waerden symbols are a set of mathematical symbols used in the field of algebra, particularly in the context of algebraic geometry and invariant theory. They are named after physicists Leopold Infeld and Bartel van der Waerden, who introduced these symbols to facilitate the notation associated with the transformation properties of certain types of algebraic objects.
The Hunter–Saxton equation is a nonlinear partial differential equation that arises in the study of certain physical and mathematical phenomena, particularly in the context of fluid dynamics and optical pulse propagation.
A holonomic basis is a concept in the field of differential geometry and the theory of differential equations, particularly in the study of differential forms and integrability. In a more specific context, a basis of a tangent space in a manifold is said to be holonomic if the basis vectors can be expressed in terms of a coordinate system. This means that the basis elements can be derived from the standard differential of the coordinates.

Pinned article: Introduction to the OurBigBook Project

Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
We have two killer features:
  1. topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculus
    Articles of different users are sorted by upvote within each article page. This feature is a bit like:
    • a Wikipedia where each user can have their own version of each article
    • a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
    This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
    Figure 1.
    Screenshot of the "Derivative" topic page
    . View it live at: ourbigbook.com/go/topic/derivative
  2. local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:
    This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
    Figure 5. . You can also edit articles on the Web editor without installing anything locally.
    Video 3.
    Edit locally and publish demo
    . Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension.
  3. https://raw.githubusercontent.com/ourbigbook/ourbigbook-media/master/feature/x/hilbert-space-arrow.png
  4. Infinitely deep tables of contents:
    Figure 6.
    Dynamic article tree with infinitely deep table of contents
    .
    Descendant pages can also show up as toplevel e.g.: ourbigbook.com/cirosantilli/chordate-subclade
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
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