Wave Particle Duality and its relation to the Wave Function

In summary, the wave particle duality of matter is simply the fact that matter sometimes behaves as a wave and sometimes behaves as a particle. The wave function gives us the probability spread of matter at any location. Once we know where that matter is, the wavefunction collapses and probability is one.
  • #1
torquerotates
207
0
Ok so from my understanding, the wave particle duality of matter is simply the fact that matter sometimes behaves as a wave and sometimes behaves as a particle. Ok, but I wonder if this has anything to do with the wavefunction. The wave function gives us the probability spread of matter at any location. That means that once we know where that matter is, the wavefunction collapses and probability is one. Now the part that I don't get is if we don't make the measurement, the matter is a wave and does this wave have the exact same spread as the wavefunction? That is, does the probability of finding that matter(or particle) at give point correspond to the actual amplitude of that matter manifested as a physical wave?
 
Physics news on Phys.org
  • #2
Let's take an electron to be concrete. You are making a distinction between the electron and the electron's wave function that I don't think really exists. In the mathematics of quantum mechanics, the wave function of an electron tells you everything there is to know about the electron. The electron *is* the wave function, in some sense. You have some idea, I think, of "matter manifested as a physical wave" as distinct from the "wave function." There is just the wave function.

When we say that some electron is "behaving as a wave" what we mean is that we are leaving the wave function alone for a while and not measuring anything so that the wave function does not collapse. Left alone, the wave function behaves somewhat similar to familiar water waves or sound waves, which is of course why it is called the "wave" function.

When we say that the electron is "behaving like a particle" what we mean is that we are measuring the electron's position. When we do such a measurement we find that the electron is in one spot and not spread out at all, which fits our idea of what a "particle" should be like.
 
  • #3
torquerotates said:
The wave function gives us the probability spread of matter at any location.

No. The wave function gives us the probability of a detection at a given point (be it in configuration or a momentum space or elsewhere). It is better to think of it as a state of a field. Quantum mechanics may be misleading. Quantum fields are technically more difficult but less misleading in a philosophical sense. The book "Introduction to realistic quantum physics" by Guliano Preparata, which some will certainly find somewhat controversial, nevertheless elucidates pretty well some of these points.

He writes in the Introduction:

And it is in the typical notion of "wave-particle complementarity" of the Copenhagen "vulgata" that any hope of a realistic, objective interpretation of QM fades away, leaving in its place a well defined set of rules to "compute" the statistical distributions of the outcomes of given observations (or observables) on a statistical ensemble of identical physical systems.
...
Let's begin with the idea that quantum behaviour has to do with the microscopic world only. The well-known collective phenomena of Ferromagnetism, Superconductivity and Superfluidity, whose classical impossibility is easy to demonstrate, bear witness to the fact that there exist macroscopic pieces of matter whose behaviour cannot be described by classical physics. If not classical, what is then the relevant physics? Most contemporary physicists have no doubt that QFT must be involved in the still mysterious workings of these fascinating phenomena, but, beyond a few phenomenological attempts, such as the Landau-Ginsburg approach, no real headway has ever been made into this kind of physics. And, I contend, the fallacious philosophy of QM is largely responsible for this unfortunate state of affairs. Conversely, couldn't the situation improve, indeed change drastically if we were to realize the centrality of QFT and find that QM is but some kind of approximation of QFT in a well defined, limiting physical situation?"
 
Last edited:

1. What is wave-particle duality?

Wave-particle duality is a concept in quantum mechanics that states that all particles have both wave-like and particle-like properties. This means that particles can exhibit characteristics of both a wave and a particle depending on how they are observed or measured.

2. How does the wave-particle duality relate to the wave function?

The wave function is a mathematical representation of a particle's wave-like properties. It describes the probability of finding a particle at a specific location, rather than its exact position. The wave function is used to calculate the behavior and interactions of particles, taking into account both their wave-like and particle-like properties.

3. Can you give an example of an experiment that demonstrates wave-particle duality?

One classic example is the double-slit experiment, where particles are fired at a barrier with two small slits. The particles behave like waves, creating an interference pattern on the other side, indicating their wave-like nature. However, when observed, the particles behave like individual particles, passing through one of the two slits and creating two distinct lines on the other side.

4. What are the implications of wave-particle duality in physics?

Wave-particle duality challenges our understanding of the fundamental nature of matter and energy. It suggests that particles can exist in multiple states simultaneously and that the act of observation can influence the behavior of particles. This concept is essential in understanding the behavior of particles on a quantum level and has led to groundbreaking discoveries in physics.

5. How does the wave function collapse when a particle is observed?

The collapse of the wave function occurs when a particle is observed or measured, and its location and properties become known. This means that the particle's wave-like behavior collapses into a specific location, and its wave function becomes a single point. This collapse is still not fully understood and is a subject of ongoing research in quantum mechanics.

Similar threads

  • Quantum Physics
2
Replies
36
Views
1K
  • Quantum Physics
Replies
4
Views
248
Replies
1
Views
560
Replies
9
Views
721
Replies
25
Views
1K
Replies
8
Views
1K
Replies
32
Views
2K
Replies
19
Views
4K
  • Quantum Physics
2
Replies
41
Views
4K
Back
Top