/sci/ - Science & Math

Hey /sci/, please help me out.
I'm just reading a bit into quantum physics and have arrived at the Quantum-Zeno-Effect, double-slit experiment and all that.

A term that repeatedly shows up is "observation". That "observation" changes the outcome of quantum experiments. But what's that supposed to mean?
I see that during the double-split experiment, the outcome depends on whether I put a detecting apparatus on one of the slits or not. But that's measuring to me, not observing. The difference (to me) is that when measuring, you usually interfere with the thing being measured, whereas with observation this can be very different.

What does "observe" mean in a quantum context? A human just watching (observing) something can't really change the outcome of an experiment, or can he?

Gather round, everyfag. It's time to learn Quantum Mechanics, so you stop spewing nonsense on this board.

Imagine a particle of mass m moving in Euclidean space, subject to some force <span class="math">\vec{F}(\vec{x},t)=-\vec\nabla{V}(\vec{x},t)[/spoiler]

The program of Classical Mechanics is to determine its position vector <span class="math">\vec{x}(t)[/spoiler]. Once we know that. Solving Newton's 2nd law, <span class="math">m\vec{x}''(t)=\sum{\vec{F}(\vec{x},t)}[/spoiler], with appropriate initial conditions (typically the initial positions and velocities) suffices to determine <span class="math">\vec{x}(t)[/spoiler].

In Quantum Mechanics picture, we are looking for the particle's wavefunction, and we get it by solving the Schrödinger equation: <span class="math">i\hbar\frac{\partial { \Psi }}{\partial {t}}=-\frac{\hbar^2}{2m}\nabla^2 \Psi+V \Psi [/spoiler]. This role is logically analogous to Newton's 2nd law. Given initial conditions (typically <span class="math">\Psi(\vec{x},0)[/spoiler]), the Schrödinger equation determines <span class="math">\Psi(\vec{x},t)[/spoiler] for all future times, just as Newton's 2nd law determines <span class="math">\vec{x}(t)[/spoiler] for all future times in classical mechanics. When extended to multiple particles, this equation determines the (non-relativistic) behavior of every particle in the universe.

Gather round, everyfag. It's time to learn Quantum Mechanics, so you stop spewing nonsense.

Imagine a particle of mass <span class="math">m[/spoiler] moving in Euclidean space, subject to some force <span class="math">\vec{F}(\vec{x},t)=\vec\nabla{V}(\vec{x},t)[/spoiler]

The program of Classical Mechanics is to determine its position vector <span class="math">\vec{x}(t)[/spoiler]. Once we know that. Solving Newton's 2nd law, <span class="math">m\vec{x}''(t)=\sum{\vec{F}(\vec{x},t)}[/spoiler], with appropriate initial conditions (typically the initial positions and velocities) suffices to determine <span class="math">\vec{x}(t)[/spoiler].

In Quantum Mechanics picture, we are looking for the particle's wavefunction, and we get it by solving the Schrödinger equation: <span class="math">i\hbar\frac{\partial{\Psi}}{\partial{t}}=-\frac{\hbar^2}{2m}\nabla^2\Psi+V\Psi[/spoiler]. This role is logically analogous to Newton's 2nd law. Given initial conditions (typically <span class="math">\Psi(\vec{x},0)[/spoiler]), the Schrödinger equation determines <span class="math">\Psi(\vec{x},t)[/spoiler] for all future times, just as Newton's 2nd law determines <span class="math">\vec{x}(t)[/spoiler] for all future times in classical mechanics. When extended to multiple particles, this equation determines the (non-relativistic) behavior of every particle in the universe.

Gather round, everyfag. It's time to learn Quantum Mechanics.

Imagine a particle of mass m moving in Euclidean space, subject to some force <span class="math">\vec{F}(\vec{x},t)=\vec\nabla{V}(\vec{x},t)[/spoiler]

The program of Classical Mechanics is to determine its position vector <span class="math">\vec{x}(t)[/spoiler]. Solving Newton's 2nd law, <span class="math">m\vec{x}''(t)=\sum{\vec{F}(\vec{x},t)}[/spoiler], with appropriate initial conditions (typically the initial positions and velocities) suffices to determine <span class="math">\vec{x}(t)[/spoiler].

In Quantum Mechanics picture, we are looking for the particle's wavefunction, and we get it by solving the Schrödinger equation: <span class="math">i\hbar\frac{\partial{\Psi}}{\partial{t}}=-\frac{\hbar^2}{2m}\Psi+V\Psi[/spoiler]. This role is logically analogous to Newton's 2nd law. Given initial conditions (typically <span class="math">\Psi(\vec{x},0)[/spoiler]), the Schrödinger equation determines <span class="math">\Psi(\vec{x},t)[/spoiler] for all future times, just as Newton's 2nd law determines <span class="math">\vec{x}(t)[/spoiler] for all future times in classical mechanics. When extended to multiple particles, this equation determines the (non-relativistic) behavior of every particle in the universe.

Morning /sci/. I never visit this board, so forgive me if you guys get this request often.

Lately I've been looking up various definitions and theories relating to quantum physics/mechanics and related concepts. I'm really interested in knowing what most scientists generally agree on.

What book(s) or internet sources would you recommend I start with as someone with virtually no prior-knowledge on the subject?

please refute this argument in as many ways as you possibly can i know that their is a high probability of this to be illogical in some way and i want you guys to help me figure out how it is illogical

The way i see it their are either 2 possibilities that could happen when you die

Quantum immortality.

this is based on 3 things
1) an event will occur given infinite time if the probability of that event occuring is < 0
2) time is infinite and will exist forever
3) according to quantum physics anything is possible as it is impossible to determine the location of a particle at any given time as that particle has a (minute) chance of being anywhere

it basicaly happens like this: you die and your consciousness ceases to exist, a near infinite amount of time passes, in that time all the atoms in the universe change position so that you are experiencing consciousness again. to you this happens instantaneously after you die as you cannot gauge the passage of time with no consiousness.

their is a 1/infinity chance that your consiousness will be exactly the same etc you could exist as a space squid a trillion miles in the sky a nano second before death.

Everyone will die alot sooner then they think.

2.) argument 1.) infers that your consciousness can exist again after it has been destroyed this might not be the case e.g a man is brain dead for a split second who is bought back to life (happens all the time with NDE's and such) has actually died and the person that is left is an almost exact duplicate of the person who has died but they are not in affect the same. logically extending this you die every unit of plank time and are replaced by a near exact duplicate. since the flow of time is not constant and occurs in frames every unit of plank time their is a brief moment of non counsciousness which occurs every every unit of plank time meaning we in effect every single person dies and gets replaced by a near duplicate every 5X10^-44 seconds

>>5642901
If OP is right, Michio believe there are ways to do it. I vaguely remember he rambling about exotic matter on some of his TV appearances. Maybe he believes such "exotic matter" will be discovered and controlled in the future, which sounds much like him.

Anyone know a good quantum physics book? I would like it to be pretty general as well as well-written.

what i've gathered from my like totally layman's perspective on quantum-level dynamics is that heisenberg's theory sez that below any actually-existing particle there's the
field of probability in which the particle could be at any given measurement/moment.
what's always bothered me about this is that is this an ontological or an epistemological
assertion, i.e. is it somehow REALLY this way or is the probability-field-as-waveform of a particle
just an admission of our own inability to measure a subatomic particle's position in space sans observer? can somebody who's actually studied this shit please clear this up for me so i can go to bed?

How do you spend your free time in a way that isnt a total waste of time like vgames, movies etc

Quantum Physics!!! I've already learned most of it but what the fuck does it mean?! What does /sci/ think the implications are?

Werner Heisenberg waited. The particles above him blinked and sparked out of the air. There were quantums in the lab. He didn't see them, but had expected them now for years. His warnings to the scientific community were not listenend to and now it was too late. Far too late for now, anyway.
Werner was a lecturer for thirteen years. When he was young he watched the physics and he said to dad "I want to be on the faculty of Göttingen daddy."
Dad said "No! You will BE KILL BY SHIFTING PARADIGMS"
There was a time when he believed him. Then as he got oldered he stopped. But now in the larbatory of the University Of Copenhagen he knew there were quantums.
"This is Bohr" the radio crackered. "You must find the quantums!"
So werner gotted his photons and blew up the principle of locality.
"HE GOING TO COLLAPSE US" said the quantums
"I will slanderise him" said the nazis and he badmouthed the research of the “white jew". Werner photoned at him and tried to blow away his critisicm. But then the reich fell and the discoverie was trapped under the weight of post wartime chaos and not able to get out from scientific circles widely until much later .
"No! I must collapse the quantums" he shouted
The radio said "No, werner. You are the quantums"
And then heisenberg was a principle.

Quantum physics, quantum computing.
Discuss

Quantum Entanglement - I can't help but think it works like this:

Take two pieces of paper and put an "A" on one and a "B" on the other. Place them into separate envelopes. Send them to two friends. One friend opens his envelope and sees "B." He instantly knows the other friend's envelope contains "A."

But everywhere I read, scientists say this is not how it works and that some sort of interaction is actually taking place.

So my question is: What experiment or observations shows us that my scenario is not enough to describe entanglement and that some interaction actually takes place?

Hey /sci/, I have a question or 2 about quantum physics that I hope you might be able help me with.

How is it that just by observing something you can change its position in space-time, according to newtonian (or classical) physics they must be a force acting on an object for another to occur and if the position of the object is changing, a force must be acting on it. So where does this force come from?

Also, the act of observing an object, by light being recieved by our eyes and thus sending an electrical signal to our brains, as far as changing reality is concerened, is this limited to animals and other setietn beings? What about the blind?

Sorry if some of this might seem a tiny bit moronic, just curious is all.

Hey guys, I need to know something about quantum physics. I've been studying the main experiments and trying to wrap my head around it, and I had a question about the electron slits experiment.

You know how when they had light flashes to record where the electrons hit the back "plate" to see where they turned up, and which it was discovered that the electrons behaved differently when they were being "observed"?

Isn't that just the photons interacting with the electrons and changing their behavior: particles interacting with other particles?

How can we TRULY measure something like that without interfering with it?

I have a book on the fundamentals of atomic physics, published in 1951.

Have any basic atomic theories been refuted / altered since then?

Basically, do I have to read the book with two grains of salt instead of the usual one?

Hey /sci/
What are the mandatory requirements for getting into a decent college for Quantum Mechanics/Physics?
Also on a semi-related note, how does this make you feel?
http://www.youtube.com/watch?v=dbh5l0b2-0o&feature=channel_video_title

Hey /sci/

I'm here to ask you if you know an equation that could be used on a pipe filled with water. That matched the following variables.

1.) Pressure inside pipe
2.) Pressure outside pipe
3.) Nozzle area
4.) Velocity of water from pipe

Thanks for any help

Long time lurker here, needing some help.
I've been writing a paper for a physics course I'm doing and I can't find my results anywhere.

Simply put my experiment was how changing pressure and ratio of water and air lead to the greatest expulsion of water from a nozzle.

Can someone explain the 'trend to me' and some concepts that I could use?

This will be helpful beyond thanks.

What if quantum values and math work the same on a large scale, only seem different on paper because many other dimensions exist than X/Y/Z/time, while most our physics formulas only account for X,Y,Z and (sometimes) time. The four forces would indeed then just be one. And it could account for all the "missing" energy in the universe (dark energy, the static energy present in a proton's empty space between quirks and empty space [vacuum, not the virtual particles] itself, and probably others).

Does this make sense?

Hey, /sci/. This is going to be more philosophy than science, but if you give this post a couple of minutes, I doubt you'll regret it. It'll make you think.

So, consequentialism (and utilitarianism) are considered moral philosophies/systems/theories. Whichever word you prefer; they are... types of morality, if you will. Now, picture an amoral society. Of course we can conclude that there isn't any traditional morality. However, what about things like altruism, kindness, empathy, and consequentialism (whether for the collective good, or for self-interest)? Do you separate things like altruism which can be seen in some animals (i.e. chimpanzees) from morality since animals do not have "morality" in the sense that we do, or is this still not legitimately amoral?

Furthermore, consider this. Could consequentialism be completely avoided in an amoral society, or is it inherent in humans? On that note, I have never associated immorality with illogic, or senselessness yet consqeuntialism and utilitarianism are considered moral systems. From this, can we conclude that true amorality is impossible for current humans, or that consequentialism and altruism can still exist independent of morality? If they can exist independent of morality; is morality necessary? If they cannot; do you think true amorality exists?

Quantum Physics FTW!