Quanta & Photons

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Quanta & Photons

Postby juleschang16 » Sun Oct 07, 2018 6:30 pm

Can someone explain the key concept of "equations in quantum mechanics have variables that are quantized or discrete". What is the difference between quantized and discrete?

Becky Belisle 1A
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Re: Quanta & Photons

Postby Becky Belisle 1A » Sun Oct 07, 2018 6:41 pm

I think when it says "quantized or discrete" that discrete is just serving as a definition or qualifier for the word quantized. The difference between them is not the main point. When values are quantized they become discrete.

Laura Gong 3H
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Re: Quanta & Photons

Postby Laura Gong 3H » Mon Oct 08, 2018 1:34 pm

Quantized and discrete are intended to have the same definition here. It just means that the variables in a system has a only a number of distinct values it can be. For example, when we talk about principle energy levels, n, n can only equal to 1, 2, 3 or 4--never 1.2 or 2.4234, etc.

Dimitri Speron 1C
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Re: Quanta & Photons

Postby Dimitri Speron 1C » Mon Oct 08, 2018 4:08 pm

It is meant to draw notice to the fact that numbers in quantum equations cannot be "anything" like in a lot of classical mechanics situations. In lecture he used the example F= ma can have pretty much any number for each of those values, whereas in a quantum equation some variables will only be able to have specific values. (like 1,2,3,4...)

Andrew Lam 3B
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Re: Quanta & Photons

Postby Andrew Lam 3B » Mon Oct 08, 2018 4:27 pm

In essence, you can never have light that strikes in 1.2 photons, 5.64 photons, etc. The particle nature of light only travels in whole number of "packets".

Nathan Tran 4K
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Re: Quanta & Photons

Postby Nathan Tran 4K » Mon Oct 08, 2018 5:18 pm

Doctor Lavelle used a very pertinent example of a water faucet in his discussion of the difference between discrete and quanta variables. Essentially, the holistic view of water exiting a water faucet is comparable to a discrete value because water is seen as continuously flowing. An example of this would be water traveling at a rate of 10 gallons per minute for 10 minutes; the rate is continuous. At a certain point, there were 5.4982097 gallons of water assuming the tub holding the water started at 0 gallons. However, if we scrutinize water on a molecular level, we see that water is really just comprised of water molecules. Water travels one water molecule at a time with no values in between because this would physically be impossible. This is comparable to a quanta variable. A helpful hint is that quanta means "quantity" and quantity should evoke a sense of whole numbers.

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