Quantum Theory

My high school physics teacher told us that solid objects don't pass through each other because their electrons exchange virtual photons and repel each other as part of the electric force. But with my rudimentary understanding of quantum mechanics, it's not the electrons' charges that repel each other. It's the fact that electrons are fermions and fermions can't occupy the same quantum state (hence the Pauli exclusion principle), and thus electrons cannot occupy other electrons' orbitals. Is that correct? And does the negative charge on electrons have anything to do with the solidity of objects, or is that not a contributing factor at all?

How close does a photon (of the right frequency),have to be to an atom for absorption to take place?

I have a question for everyone who visits this part of the forums. This question applies both with genetics and particle mechanics. I have a hypothesis. The Hypothesis states that no single particle that exists is the same. That a particle in its existence will never be in the same space, time or mass. This is regardless of how that particle acts, looks alike or has same traits of other particles. That each is it own individual. This Hypothesis applies to many studies of science including Biology, Genetics, Physics, and Quantum Physics. So the question, Can a particle be the same with space, time, mass more than once? I do not believe it can. But perhaps someo…

Edit: didn't notice philosophy section - this might be more appropriate there. My bad, please move if necessary. One could argue that, due to quantum states within the brain, every moment in time our minds make an infinite number of different choices, thereby creating an infinite number of different realities every planck moment. I would argue that the only realities which sentient life experiences are those in which we, in the future, create a simulation of our own universe using starting conditions of the big bang (after 1 tP perhaps). This would conveniently be possible using quantum computers. The likelihood of us existing is approximately zero, but in an inf…

For my personal information please: A part of the electron's and proton's masses result from their electric field. When the electron and proton are close to an other, the electrostatic attraction reduce their energy (twice as much as the kinetic energy increases the electron's mass+energy). Must this energy change be included in the electron's mass to compute the orbitals? Also: this energy change isn't necessarily located at the particles (...with all subtleties associated with a particle position). This energy change is rather everywhere around the proton and the electron, where the square field (Ep+Ee)2 differs from Ep2+Ee2. Because this energy change can b…

Consider the classic example of Schrodinger's cat. Till the collapse of the wave equation we have no way of knowing whether the cat is alive or dead. Assume that there is a mirror in the enclosure and the cat looks in the mirror at the same instant that an external observer looks at the cat. Then is the cat truly "alive or dead"? The cat expects himself (or herself) to be alive but the external observer (assume that the external observer has certain privy information about the cat and the cat is chronically ill) expects to find the cat dead. Now do we need a third observer to collapse the resultant wave function to arrive at some realistic conclusion? …

Hello all. This is my first post here, so I hope I don't do anything wrong. I would have posted this in a general 'quick question' forum if there was one, but I figured this would be a good place to ask. So, I've been trying to understand this for a long time, but so far, no one has been able to sufficiently explain it to me. My question comes down to this. Since quantum theory tells us, there is a smallest significant distance; the planck distance, and thus a smallest possible significant time (The time it would take to move over a distance of 1 planck distance going with the speed of light.) how would 'change' then be possible? What I mean by that is, that as I un…

Hello you all! The Bardeen-Cooper-Schrieffer theory (BCS) makes nice explanations and predictions for the behaviour of traditional superconductors. It relies on electrons making pairs at cold - and pairs of fermions are bosons. Some texts about BCS claim that the electron pairs build a Bose-Einstein Condensate (BEC); other texts don't. Hyperphysics yes, en.wiki yes, de.wiki yes, es.wiki no, fr.wiki "some analogy", it.wiki no, pt.wiki no - textbooks diverge as well. So I wanted to check whether the original BCS theory did include the BEC of electron pairs. Here are the Nobel lectures by Bardeen, Cooper and Schrieffer: NobelLecture1972BardeenCooperSchrieffer.z…

Given is a sufficiently flat spacetime. Define the vector [math]\mu= (E/c^2, p/c) [/math], invariant under the Poisson group. mu is the norm of the mass. [math] < \mu, \mu> =m^2[/math] Or [math] |m|=\mu [/math] From this we can get [math]c^4m^2=E^2-p^2c^2[/math]. In the common understanding, [math]E=pc[/math] so that the mass of light is zero. However, for radiation emitted from an atom, or particle annihilation, in the center of momentum frame, the emission is radially symmetric. This implies that the total momenta of an electromagnetic quanta is zero, giving nonzero mass; [math]m=h\omega/c^2[/math].

Hello you all! For an electromagnetic wave (spin=1) we write the wavefunction as a vector (or little more), depending on position and time. For an electron (spin=1/2), as a scalar (though the angular momentum is treated separately then). What mathematical object shall represent a particle with spin=2? Thank you!

As we are aware Richard Feynman proposed that a particle can take any path in a double slit experiment (albeit hypothetically) but ultimately probabilities resolve to a deterministic pattern (interference pattern). What we know for certain is: a) Interference exists irrespective of the number of slits (should be greater than 1) b) Interference exists for electrons, buckyballs etc in addition to photons Then is this model not implicitly deterministic? Although there exist an infinite number of potential pathways for a photon on the incident side of a slit, the presence of a slit seems to ensure that at least 1 (actually several) photons pass through this? …

HI, (Before I ask my question I just want to let you all know that I'm not a Scientist or a student of science. Not that I wouldn't love to be.) If someone has a little extra time would you mind explaining quantum entanglement? I understand "Spooky action at a distance" hahaha... What I don't understand is how it was proven. What were the steps that were taken to come up with that conclusion? What is connecting the atoms? is there more to it then one changing the other? Ok, here comes the crazy question lol... Could the fact that we feel empathy have anything to do with quantum entanglement? I have a sucky education... One year of community college!…

Hey all, I'm not sure if this should go in Quantum Theory, or Amateur Science, so I just went with Quantum Theory! Since I'm just getting into this stuff, my question is pretty basic: are things REALLY fields, and are things at the quantum level REALLY probabalistic? The reason I ask this is because I'm starting to get confused on what to use as a mental image or a visual model, and what these things actually represent. My understanding of quantum field theory is that there is a field for every subatomic particle we know of: an electron field, a quark field, and then various force-carrying fields such as a gravity field, higgs field, etc. Following from this t…

Individual quantum is a particle but it moves forward in a wave-like manner, a wave which has a crest & a trough,just like a sea wave.This nature of the individual quantum is in total contradistinction to what happens in the macro world where a bullet moves forward in a straight line.your thoughts?

I have a question about the shape of the wave of a single photon entering the double-slit experiment, in time and space. Although I thought it was basic, it seems to be difficult because I did try other fora and Wiki, but nobody could give an answer. This is my last shot. Of course the interference pattern shows the shape, the envelop, in time. But because I don't have accurate measurement data (most pixtures of the pattern are simple and idealised) I cannot construct it from there. So I wonder if there is the (rough) formula, only as an approximation. Not exactly, because that will probably be of a high mathematical level.

Single subatomic particles that can occupy numerous areas of space at one time and the entanglement that is a physical phenomenon that occurs when particles like small molecules in the size of small diamonds, interact and then become separated. Before the interaction each particle is described by its own quantum state. After the interaction the pair can still be described with a definite quantum state but each member of the pair must also be described relative to one another and then each member of this pair is indefinite in terms of important factors such as position, momentum, spin, polarization, etc in a manner distinct from the intrinsic uncertainty of a quantum …

I was reading about the Hall Effect and i thought i understood it, then as I was reading further I don't. What i understood is that if you place a magnet near a copper wire the electrons go in the opposite direction. Theory says that a curent is flowing trough the wire from top to bottom, and the driftting electrons are flowing from bottom to the top. And this is confusing. What do i miss in my knowledge ? And second i was reading about Magnetic force exerted on a current carryin wire. I attach a picture . Can someone explain teach me the intuition of thing in the picture ?

Hi all, This is my first time here, please help me along Qn: Calculate the De Broglie wavelength of a neutron with a translational kinetic energy = kT at 300K. k = boltzmann constant = 1.38 x 10^-23 JK-1 Solution: λ = h / p = h / (2mE)^1/2 (E: kinetic energy) = h / (2mkT)^1/2 (substitute E with kT, the translational kinetic energy) why do we use translational energy = kT here? I googled, most of the webpage suggest KE = 3/2 kT (or kBT) (kB: boltzmann constant) I am trying to understand why the question omit 3/2? To my understanding 3/2 is to account for the 3 axis of direction, x, y, and z direction. So instead of KE = 1/2 kT, we get 3/2 kT. Any guidance is appreci…

Are standing waves = to " a regular distance"? Or does this only apply to QM? The reason I ask is because of how a typical distance in the physical real world " also" applies to time. Time I mean the speed of light, and "typical distance" I mean " example" from your house to your job. Yes I know about atomic clocks and time dilation. Not sure if c is applicable to " ordinary time though" as in 12: 40 pm, 1:20 am and so fourth. Distance from x to dx, is this another way of describing what I am asking? The way I am thinking is that c " time" which does not exist in this dimension being constant in the known universe must be = to " any distance, ve…

I find this subject interesting , yet at the heart of quantum theory. If anyone has any eureka feelings about " spin" at the quantum level please could you share them !

I am not able to understand exactly why operators are required in Quantum Theory, what is its use According me its like normal + - * and / operator used in mathematics . for example a+b = some value, so here + is an operator, so I want know is the operator used in Quantum Theory also the same,does it work in same manner how it is different Thanks a lot in advance for replies

Solargraphy is extremely long exposure photography. I was wondering if cameras could be set up on say, on satellites, and at different elevations around the planet, to take combined, long term photographs of the entire planet, portions of nature, and, more importantly, human populations. If we had a photograph showing human activity over the course of say 10 years, it would probably be blurred beyond recognition, but what if we used high resolution, or even a 10-year video being sped up to a speed of minutes, would we be able to retrieve data from the different patterns of motions? I was wondering if things like this might be able to provide statistical data about every…

A qubit which is the base unit of a quantum computer (analogous to bit in classical computer) can be superposed. if there is a 3 bit quantum computer it can simultaneously store 8 states. However how stable are these 8 states. Can one state for example be corrupted? Can 2 states in the qubit "interfere" with each other? How reliable are these constructs? How feasible is it to build a quantum computer? What is the current research on the subject?

Hello Scienceforum.net users, I have multiple (somewhat ludicrous) ideas for a "photon cannon" type of idea. The theory is that a large piece of artillery could store up a super dense "energy ball" of photons via a large array of hypersensitive solar panels and would then be placed in a silicon-lead alloy projectile that would fire from the artillery and cause a mass area of high radiation along with the possibility of a large electromagnetic pulse. (This is in theory though. I'm not planning on becoming the next Robert Oppenheimer) My question is though, how would I be able to store and condense a mass amount of photons for a prolonged period of time? (note that if m…

How does Quantum mechanics explain diffraction? If light goes throught a single slit it is diffracted, the waves bent in the slit. In classical waves this is caused by the carrier, which consists of particles which radiate spherical. But a EM-wave has no carrier. So why does the wave bends in exactly the same way as classical waves?