free particle

If the potential is zero (or constant) everywhere, one describes a free particle.

An electron in a metal normally behaves as a free particle.

It is usually assumed, as here, that a free particle impinges on the barrier from the left.

This ensures that the free particle moves at the expected velocity with the given momentum/energy.

The second term is the free particle propagator, corresponding to i times a diffusion process.

Consequently, the propagator becomes that of a free particle and the field is no longer interacting.

For a free particle with zero electric charge, the full set of equations are:

For a free particle the potential is .

In the case of the free particle, the conserved quantity is the angular momentum.

Two free particles may begin at the same point on the surface, traveling with the same constant speed in different directions.

The net charge could be also placed in the complex scalar field condensate instead of free particles.

Under sufficiently extreme conditions, quarks may become deconfined and exist as free particles.

In both cases, the particle behaves as a free particle outside of the barrier region.

When quarks are in extreme proximity, the nuclear force between them is so weak that they behave almost like free particles.

The Klein-Gordon equation for a free particle has a simple plane wave solution.

For example, consider a free particle.

Note that the normalization of the path integral needs to be fixed in exactly the same way as in the free particle case.

In such a plasma there are no hadrons; quarks and gluons become free particles.

However, gluons are never observed as free particles, since they are confined within hadrons.

A simple example of this is a free particle, whose energy eigenstates have wavefunctions that are propagating plane waves.

The typical example is the free particle with the space of square integrable functions on three dimensional space.

Linearity: The previous assumptions only allow one to derive the equation for plane waves, corresponding to free particles.

A free particle (mass m and velocity v) in Euclidean space moves in a straight line.

Drywasher - A mechanical apparatus used for separating free particles of placer gold from dry sediments.

In the more common Schrödinger picture, even the states of free particles change over time: typically the phase changes at a rate which depends on their energy.