Quantum Theory

Hello ladies and gentlmens. In this topic i would like to invite people interested in quantum mechanics. Im 4th year bachelor student and would like to know more about the origin of tunnel effect. Why is it happening?

THIS PAPER has certain equations in its final section, the author has no degree in physics...... However the author linked me to THIS PAPER saying he had his equations taken from that. Are the two related ? I couldn't make out anything from the first?

Hi all, I've started a new YouTube series on the ontology and physical basis of Quantum Mechanics with Episode 1 on Wave-Particle Duality and the Single Slit experiment, would love your feedback! Channel promotion removed by moderator per Rule 2.7 Episode 2 will be out in a couple of weeks and cover the Double Slit experiment with observation (my favourite experiment of all time!) Hope it's of interest.

Hi I'm having difficulty with the part of inserting the graph in MATLAB using the plasmon polariton surface equations. Estou seguindo essas equações e tenho que gerar esse gráfico e não estou conseguindo alguém me orientar? Constantes %format long format short e syms m=9.11*10^(-31) % Massa do elétron - KG q=1.602*10^(-19) % Coulomb - c eo=8.8541878176*10^(-12) % Constante de permissividade do vácuo - F/m C = 300*10^6; % Velocidade da Luz em m/s n=8.45*10^(28) % n is the number of electrons (densidade do eletron) [8] oo=5.7*10^(7) % σ (COBRE)= 4.3*10^(7) condutividade (Siemens/m) = (S/m) h=6.626*10^(-34) % h constante de Planck - J⋅s p…

This follows on from the thread 'what makes an electron orbit', but it's ten pages long (and counting) and gets a bit awry half way through. So I decided to start a new thread, and include a poll, where you can cast your vote, and include your reasoning to back it up. I've kept the description simple to just waves and particles, so it allows anyone to explain what they mean by (for instance) a particle. Note, that I have not studied QFT, so I'll only provide a basic description from what I've been told, and then I'll provide a few examples to the whole wave-particle duality conundrum. It would be nice to hear a few expert opinions, as I know there's a few on here …

I suspect the blurred lines are a result of the uncertainity of which atom will absorb the light rather than a matter of timing. From the reference frame of light, emission and absorption are simultaneous events.

if one particle decays by two, if even parity is not conserved, will the parity of the final state be well defined?

For more than a century, the famous dual slit experiment (performed on particles such as electrons) has been baffling scientists who couldnt explain why the particles where 'behaving like waves', and invented an irrational 'particle-wave duality' to explain it. Most scientists take this 'explanation' for granted and mechanically repeat it, even if they assure us that they dont understand it. 'If you think you understand quantum mechanics, then you don't understand quantum mechanics', as Feynman noted. The reason why they dont understand it is because it is illogical and contradictory. You cant understand a contradiction, because there is nothing to understand. This exp…

I have been searching for the answer to the question of whether either observation or consciousness can influence the outcome of the double slit experiment for several years now and I feel I have made a lot of progress in understanding the problem but I have possibly reached the limits of my expertise to come to any definite conclusion except to say that this is an extremely thorny issue with no easy answers. It is my understanding that it is nearly the mainstream conclusion that observation and consciousness can influence the outcome of the double slit experiment. I have little interest in the philosophical or psychological aspects of this issue as long as th…

And can you explain the results of the Stern Gerlach experiment, which showed that the spin of a charged particle can have only two values, plus or minus 1/2????

I found a fidelity between initial and final state (pure). Now when t=0 , I am getting F=1 When t=pi/2(90 degree) i am getting F= (4.5)(10^-5) But my teacher says this is wrong and I should get F=1. Why should I get 1 and Why am I not getting 1? What's wrong with my calculation? Here alpha is the coherent state and its value is sqrt 5 Adobe Scan 31-Aug-2021 (2).pdf

That remark was in reference to "Forget about time travel. I wish ordinary travel were restored"...remembering that some of us are still in lockdown. Are you referring to this paragraph? "The quantum laws of physics do permit exotic matter to exist, and it has been created in the laboratory in very tiny amounts: in the so-called Casimir vacuum between two electrically conducting plates, and in the so-called squeezed vacuum that is generated by optical physicists using nonlinear crystals." I admit my understanding of exactly what he is saying, is probably somewhat flawed. Swansont, can you elaborate on what exactly your objection to Thorne's rundown is, as dum…

Hello you all! Here, I suggest photocathodes that resonate at the light's frequency like a radiowave antenna to improve the sensitivity. As usual, I didn't check the state of the art, and since antennas for light exist already on solar cells, I could well be late. To increase the field, the cathode has a sharp tip like at some electron guns, and it shall resonate well, but metals are lossy at visible frequencies. Silver must be the best choice, followed by aluminium if the light isn't blue. From the CRC Handbook of Chemistry and Physics, section "optical properties of metals", for silver at 2eV = 620nm = 3*1015rad/s: The extinction coefficient k=4.18 so the current i…

if a beam of spin-up-along-vertical particles are put through a horizontally aligned stern-gerlach apparatus, a left horizontal beam and a right horizontal beam are produced. On either of these paths, if the vertical spin in measured, 50% of them will be found to be spin down-along-vertical. If on the other hand, no measurement at all is made until after the point where the two paths are joined, none of them are found to be spin down along vertical at all. question: what happens if one path is made longer than the other but the paths are kept joined? If the long path is made greater than c/t (where t is the measured transit time and c is the …

The double-slit experiment got me on this journey to try to manifest what I want. Is there any ways you guys manifest that you can show me?

The quantum teleportation is based on the quantum Entanglement; Imagine two particles, like two photons. They interact in a point and their function states create a single function state. . The first particle is then analyzed in a lab, called lab A. And the second one in lab B; an experiment accomplished on the first particle will change its function state and its behaviour it's going to be appreciate also on the second particle. They receive the same perturbation, even if the distance between them. The measurement on the first, will define instantly the state of B. But, in this phenomena there isn't migration of information. However, Imagine a third parti…

How scientist could detect "undetectable particles"? In the case of neutrinos this question is very common. In fact neutrinos reply to weak and gravitational interactions, so when they go across a beam of matter, they can't interact with its atoms ( On electromagnetic or strong interactions) .There are some indirect ways to find them, thank to Beta decay. -Electron neutrinos Electron neutrinos are the easiest to reveal; in neutrinos detectors there is a great amount of CCl4 (Carbonium tetrachloride); when neutrinos from the Sun or deep space impact with Clorium (Cl N=17), they convert it in Argon gas (Ag N=18) and there is also an emission of an electron. …

The solar neutrinos problem has represented one of the most important issues in the history of physics. It concearned a discrapancy between the number of neutrinos which reach the Earth from the Sun predicted by the physics models and the effective number of neutrinos observed in experiments. -Flow expected Solar neutrinos with photons are created in Sun's core thank to the nuclear reaction between Hydrogen cores, which form Helium; In this type of reaction is created an amount of neutrinos. The flow of neutrinos could be calculated by the brightness of the Sun, which is propotional to the amount of energy released from it. n ν = 2 L Q − 〈 q …

I imagine it must be difficult to represent a massless particle like the photon with this type of field. How does QFT interpret the photon, and if the theory allows it?

I was recently reading about atomic structure's journey, when i saw the electron probability distribution graphs for some orbitals. Why is the electron probability density maximum "at the nucleus" for s subshell ? does it have any physical significance? the confusing part for me is that the probability of finding an electron would be the least at nucleus, so how come probability density is maximum? P.S. I am a high school student, so it would be extremely good if someone could explain this to me in a simple way

I recently learnt that according to quantum mechanics, the probability of finding an electron anywhere(except nodes) is non zero. The probability of finding the electron of the sodium atom in my vapour lamp, in Andromeda galaxy is, although very very small, but non zero. I am unable to wrap my head around this fact. Is the aforesaid statement just a mathematical consequence? Could someone please explain this to me? P.S. I am a high school student, so it would be extremely good if someone could explain this to me in layman terms

Quantum mechanics introduces the concept of identical particles, and according to the quantum number of spin, particles are divided into two categories: fermions with a half-integer spin and bosons with an integer spin. Are identical particles really exactly the same? In fact, the "identity" here is statistically identical, that is, "identical particles" refer to particles that satisfy the same statistical laws (Fermi statistics and Bose statistics). Specific to a single particle, it can still have different states, such as spin states. There is another difference between individual particles, which is the particle chirality, a brain-burning concept. According …

One of the most unpleasant thing about quantum entanglement is that it can't be used for information or energy transfer. No-communication theorem - Wikipedia Some scientists, however, are trying to overcome this problem: Squeeze light to teleport quantum energy | New Scientist However this method doesn't seem to be practical for any significant amounts of energy, if at all. Do you think there could be some quantum effects which may allow us to transfer significant amounts of energy for a large distances with high efficiency? Possibly something on the verge of classical and quantum physics?

Would I be right to understand that this is a description of the impossibility of knowing the simultaneous position and momentum of a particle? If it is not an example of the "how not why" question could I ask why (or how) this is the case? Is this an observer related phenomenon or is it the case that the particle itself cannot actually be in a particular place with a particular momentum? (as applied to a particular frame of reference if that does not in itself imply an observer) I wanted to post in this thread https://www.scienceforums.net/topic/125204-life-was-inevitable/?do=findComment&comment=1178225 but thought it was better to…

Hello. I know that with the help of excitons you can get a superconductor, but I do not know how this is realized, because an exciton has no charge. I was wondering how this happens and at what temperatures. Thanks in advance.