nLab
quantum fluctuation

Contents

Context

Vacua

Algebraic Quantum Field Theory

algebraic quantum field theory (perturbative, on curved spacetimes, homotopical)

Introduction

Concepts

field theory:

Lagrangian field theory

quantization

quantum mechanical system, quantum probability

free field quantization

gauge theories

interacting field quantization

renormalization

Theorems

States and observables

Operator algebra

Local QFT

Perturbative QFT

Contents

Idea

The theory of quantum physics (quantum mechanics, quantum field theory) is at its heart probabilistic (see at hidden variable theory). Any quantum observable in a given quantum state has a probability distribution with some finite width around its mean value. A measurement will find the observable with given probability in any one of its possible values, and hence it seems as if it “fluctuates”. This intrinsic randomness in quantum physics is referred to as quantum fluctuation. (See also at measurement problem.)

In particular the above holds for the vacuum state of any quantum system. Hence even when a quantum system is a little “excited” as possible, it still quantum fluctuation. These are therefore also called vacuum fluctuations.

References

Last revised on May 17, 2019 at 16:06:29. See the history of this page for a list of all contributions to it.