Physics, mathematics and quantum physics

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Are there any phisicists, mathematics and quantum physicists on these forums who can tell me what is a good place to start if I want to study these things? I think I would have to start from the ground, even though I know a bit about these things from before. My knowledge is just too fragmented and incoherent, and I don't know the maths at all.
But I want to learn, I just don't know where to start.

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@Cyracuz,

I recently read a couple of good books on quantum physics. They went back to the early part of the 20th century and explained the concepts pretty well.

"physics, math, and quantum physics" is pretty vague. What are you actually wanting to learn about?

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@DrewDad,

Well, I understand some relatively complex ideas from physics in a more philosophy, layman science kind of way. I know what quantum physics is, what it applies to and some of it's limitations.

But I can't use physics to calculate the force of something, for instance. Not on paper at least, though we all use the principles to do normal daily tasks.
I can't describe a movement with mathematics. Even a simple movement I understand completely, I can't write it down, because I don't speak the language.

But what I want to know specifically... How about how much force it takes to lift 1kg mass 1 meter, to start simple.

And from there, what is the physics term for force, and how is it explained? And the same for matter. Gravity is a factor, and that one is still not clear to even the most knowledgable scientists from what I hear.

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I recommand "In search of Schrodinger's Cat" by John Gribbon. He gives a good lay understanding of the science and the story of how our understanding of Quantum Physics was developed.

More importantly he avoids the pop-science silliness that many people like to indulge in regarding metaphysical truths or imagined ways that Quantum Physics sheds light on everyday experience.

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@ebrown p,

Oh... and if you want to really understand Quantum Physics, you are going to have to learn the maths.

Learning the math is the first step in any serious study of these topics.

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@ebrown p,

Yes, that is what I have started thinking. But where to start? Smile

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@Cyracuz,

Cyracuz wrote:

But what I want to know specifically... How about how much force it takes to lift 1kg mass 1 meter, to start simple.

OK, this is classic mechanics, not quantum physics. http://en.wikipedia.org/wiki/Analytical_dynamics

Quantum physics has to to with particles at an atomic level.

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I would start with the Feyman Lectures on Physics, then onto his Six Easy Pieces, which is available on CD, then on to his Six Not So Easy Pieces

Feynman also wrote on Quantum Electro Dynamics with QED, The Strange Case of Light and Matter.

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@Cyracuz,

http://en.wikipedia.org/wiki/Force

Quote:

In physics, the concept of force is used to describe an influence which causes a free massive body to undergo an acceleration.

...

An applied force has both magnitude and direction, making it a vector quantity.

...

Today, this acceleration due to gravity towards the surface of the Earth is usually designated as \vec{g} and has a magnitude of about 9.81 meters per second squared (this measurement is taken from sea level and may vary depending on location), and points toward the center of the Earth.[27] This observation means that the force of gravity on an object at the Earth's surface is directly proportional to the object's mass. Thus an object that has a mass of m will experience a force:

F = m*g

http://en.wikipedia.org/wiki/File:Freebodydiagram3_pn.svg

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@Cyracuz,

Cyracuz wrote:

How about how much force it takes to lift 1kg mass 1 meter, to start simple.

The force required is anything greater than (and in the opposite direction of) that exerted by gravity.

Force, however, only describes how hard the object is being pushed. The energy used to raise 1 kilogram one meter is 9.81 Joules (one Joule is equal to a Newton-meter, or one Newton exerted over the distance of one meter).

http://www.ftexploring.com/energy/power_1.html

Quote:

Confused about the difference between power and energy? I don't mean the kind of power politicians crave. I'm talking about the kind of power related to energy that you learn about in physics.

In physics, power and energy do go hand in hand, but they're not the same thing. Whenever energy is changing or moving, there also is power, telling us how fast the energy is being transformed.

Energy, as described in other pages on this site, is the property of matter that makes things happen. To make things happen, energy must change form or change locations. Power is a measure of how fast those energy changes are happening.

Energy comes in set quantities like Joules (1 Newton-meter), foot-pounds, Calories, or BTU's (British Thermal Units).

Power is a rate. In physics, rates describe how something changes with time.

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It depends on how well you want to learn it. If you want to have an approximate idea, there are probably any number of popular works. If you want to really learn it, you have to learn calculus and elementary physics from actual text books before you can even start. Statistics wouldn't hurt either.

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@Cyracuz,

Cyracuz wrote:

I think I would have to start from the ground, even though I know a bit about these things from before. My knowledge is just too fragmented and incoherent, and I don't know the maths at all.
But I want to learn, I just don't know where to start.

Well, where would you be starting from? What do you know so far?

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@Cyracuz,

I would recommend finding a good book on the history of Physics/Quantum Mechanics. It should mention most of the famous people and the main concepts as they occurred. Given this background, then pursue general books on a specific topic, say for example radiation or string theory, then try the Maths to follow the deeper arguments you can meet by reading the detailed evidence and analysis.

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@Cyracuz,

(see pm)

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@Ionus,

Thanks guys Smile

Like I said, what I know from before is fragmented.

I know about gravity, in the same way I understand what's happening when a car drives past. Where the energy comes from, and how it is directed into the force needed to move the car through the propulsion system.
I know about quarks and photons. I know that light is a particle and wave, and that the potential location of the particle is related to the wave function.

And I have read some about the hisory of physics and how and why quantum physics was developed.

I need to learn the mathematics behind it, as you all are suggesting. I really should get me some high school textbooks. Smile

Quote:

...reading the detailed evidence and analysis.

Yes, that's what I want. I am so amazed by all the discoveries I read about, but I keep asking "how do you know?"..

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@Cyracuz,

Quote:

I know that light is a particle and wave, and that the potential location of the particle is related to the wave function.

What does this mean? Can you tell me an experiment that I could do to show that light is a particle? Can you tell me an experiment that I could do to show that light is a wave?

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@ebrown p,

The double-slit experiment "explained".

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@Cyracuz,

Most of what is known is from bashing enough bits together to obtain results that prove a certain particle exists. Usually there are mathematical models and symmetry concepts that suggest the existence of the particle that is being searched for, but there are some interesting border areas. What makes a wave a particle ? What happens on an event horizon ? How far back into the Big Bang can we really use physics before it becomes philosophy, or for that matter how far can we break down components of matter before we hit philosophy ?

What is the true nature of matter if everything is a wave at its base ? Perhaps there is no matter as a seperate identity, perhaps it is a function of strings and gravity.

It is a lot of mental fun and I hope you continue. I wouldnt bother with the maths if you want to improve your general knowledge first. A good history book on physics will answer your question "how do you know?"..

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@Cyracuz,

Cyracuz wrote:

I need to learn the mathematics behind it, as you all are suggesting. I really should get me some high school textbooks.

High School books are not going to cut it. To know enough mathematics to understand quantum mechanics, you need matrix algebra and multiple-variable calculus. You want to check a university library for books on these subjects.

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I would suggest ordering older books online, which is normally pretty cheap.

Here's what I have:

Calculus , James Stewart 5th
Linear algebra and applications, Otto Bretscher
Intro to Probability, Roussas
Real Analysis, Bartle and Sherbet
[For abstract algebra, I just have a general dover book, which is ok. It's: Modern Algebra, Warner]

Physics, Tipler Mosca
Matter and Interactions 1 and 2 , Chabby and Sherwood

That should cover the basics, and will also give you enough math to learn some higher physics stuff too.

**A warning on the Linear Algebra book, if you are looking for efficiency to just get a decent understanding of the material in a relatively short time, I'd go with Strang's version. Much quicker.**

Once you have an ok math background, everything gets easier.

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