What can collapse a wave function?

In quantum mechanics, wave function collapse occurs when a wave function—initially in a superposition of several eigenstates—reduces to a single eigenstate due to interaction with the external world. Historically Werner Heisenberg was the first to use the idea of wave function reduction to explain quantum measurement.

Do photons have a wave function?

Because photons have zero rest mass, no wave function defined for a photon can have all the properties familiar from wave functions in non-relativistic quantum mechanics.

Does the detector collapse the wave function?

It is true that the wave function can collapse even though there is no interaction with a detector.

Does wave function collapse instantly?

Yes the collapse of a wave function is instantaneous. No experiment to date has uncovered any finite speed for this collapse.

What has the wavefunction collapsed to immediately after the measurement?

The instant we make the measurement, the wavefunction collapses to one of the three basis eigenstates. If it collapses to |1⟩, then the value for momentum associated with the state is measured.

Why do atoms change when observed?

When a quantum “observer” is watching Quantum mechanics states that particles can also behave as waves. Once an observer begins to watch the particles going through the openings, the picture changes dramatically: if a particle can be seen going through one opening, then it’s clear it didn’t go through another.

Are photons wave packets?

The photon’s existence is embodied in a wave function, which gives the probability of measuring the photon at any time, place, and frequency. The wave function for a single photon is usually a “wave packet”–nearly zero everywhere except in a narrow range of space and time.

Do photons have spin?

Electrons and quarks (particles of matter) can have a spin of –1/2 or +1/2; photons (particles of light) can have a spin of –1 or +1; and Higgs bosons must have a spin of 0. Though particle spins are tiny, they have an impact on our everyday world. The spin property of photons allows us to create 3D movies.

What is the collapse postulate?

According to the collapse postulate, a measurement precipitates a discontinuous jump to one of these terms; the others disappear. That is, a theory that could underwrite the collapse process just described without ineliminable reference to measurement would constitute a solution to the measurement problem.

What is Quantum Mechanics probability?

In quantum mechanics, a probability amplitude is a complex number used in describing the behaviour of systems. Born was awarded half of the 1954 Nobel Prize in Physics for this understanding, and the probability thus calculated is sometimes called the “Born probability”.

What happens after measurement quantum mechanics?

We have a qubit (a superposed quantum state) formed by some linear combination of |0> and |1>. After measurement, it becomes a classical bit ( 0 or 1). In this case, the evolution of the larger system can be described by unitary evolution, and we can use the projective measurements to measure things out.

What is the wave function of a photon?

Let’s start with the example of the wave function for a photon that has been shot from a laser and aimed at a photographic plate. The photon must pass through a barrier with two slits before it hits the photographic plate. This is the famous Double Slit Experiment. The wave function is the equation which describes the changing or “evolving” photon.

What happens to a photon when it is absorbed by electrons?

In this case, the photon is absorbed by an electron in the photographic plate, which creates a dark spot on the plate. Upon measurement, that is, this interaction, the probabilities calculated by the wave function instantaneously convert to a 100\% probability for the specific dark spot and 0\% everywhere else.

Does Consciousness collapse the wave function?

In the 1920’s and 1930’s, some quantum physicists considered the possibility that consciousness collapses the wave function. This possibility is suggested by an odd aspect of the Double Slit Experiment. When the “which path” information is discovered about the quantum particle in any manner whatsoever, the wave function collapses.

What is the collapse of a wave function called?

When the atom interacts with an object (is “measured”), the wave function collapses. Upon collapse, the atom is measured as having one of the two possible energy levels. In this animation, the collapse of the wave function is called “decoherence.”