Tunneling Definition and 247 Threads

Is it possible to achieve commercially viable nuclear fusion in purely electrostatic quantum tunneling way?What should be voltage of electrostatic field (no particles bombarment) to overcome Coloumb bareer and make tunneling fusion probable?

It is a theory, but quantum computing could most likely out perform classical computers. In this regard, would it limit the progression of AI if it could go beyond classical computing? Assuming that quantum computing catches up and out performs classical computers, will computer engineers have...

Good day, everyone! Lately I faced the necessity of solving a problem from a field I know literally nothing about. So I just made an online research but without success. Any help (hints, good sources, relevant equations) would be greatly appreciated! Homework Statement Gold nucleus (Au...

I'm calculating the band-to-band probability using the WKB approximation given by T=exp(-4*lamda*sqrt(2*m*Eg^1.5)/(3*q*hbar*(deltaPhi+Eg))). I am wondering which unit of the plank constant is used here? The one in J-s which is 6.62e-34 or in eV-s which is 4.13e-15? However, the former one...

can anyone tell me what's the formal analogy between electron tunneling in terms of quantum mechanics and electromagnetic waveguide modes at frequencies below cutoff ?

On 8/16/09 a alxm wrote... Macroscopic objects have a quite definite location, and do not tunnel to any appreciable extent. Another way to say it is: The location of a macroscopic object is only a little bit random, and the probability of tunneling is very very small. Is that correct...

Hey everyone, For my a research project on quantum tunneling I have to tie in math somehow, so I was wondering if anyone could help me learn to calculate the probability of a wave (preferably like an electron or electrical voltage) of some sort passing through a rectangular barrier, which is...

I have no idea how to solve these problems. Picture is attached. An electron with energy E is incident on a barrier of height U0 and total width L. It enters the barrier at x = 0, from the left. 1) For an electron with energy E = 6 eV and a barrier of height U0 = 12 eV, at what penetration...

Hi, I'm doing a research project for my high school physics class. I originally set out to research touch screens but was disappointed with how simple the mechanics of the iphone are (or at least the basic physics of it). I continued researching and found that soon Quantum Tunneling may be...

I'm trying to find the experimental evidence for quantum tunneling during a fusion reaction. Take the simple D + D -> T + P reaction. I know that the energies required to make this happen are much lower in actual experiment than what would be predicted by Coulomb's model of the electrical...

I was on another forum and somebody was talking about quantum tunneling and that walking through walls was not impossible. Just highly improbable; the probability of it happening is older than the universe. Some reason it blew my mind away, even though not much was said. Anyone have more insight...

Hello, With regards to a Youtube video- Spin polarized tunneling - video #10: , could some one familiar with electronics provide a circuit or diagram for this to work? Also what type & size of barrier could be used? This should be fairly easy for anyone familiar with electronics, so any help...

I have 2 questions... I was told that the transmutation of Li-7 to Be-8 by proton collisions at energies below the classical barrier verifies the QM description of the weak interaction cross section. Firstly, I found the leap in logic very confusing - does the weak force have a role in...

This may be a bit of a silly question, but I'm wondering if it is feasible to design a freshman level lab experiment using a STM? For example, let's say the lab is simply intended to give the students a better appreciation of how a STM operates within the framework of quantum mechanics, with the...

Hi. Firstly, can a particle every be found within the potential barrier? I've used the search function to look for an answer for this question, but I didn't really get anything conclusive. However, from what I gather, since there is a probability associated with it being 'found'(meaning it...

Would it be possible to tunnel directly to the center of the Earth using currently available means, or would the centrifugal effect cause you to unwittingly continue on toward the nearest point on the surface so that you emerge near the point where you began without ever having gone beyond a...

Homework Statement Suppose a tunneling current in an electronic device goes through a potential-energy barrier. The tunneling current is small because the width of the barrier is large and the barrier is high. To increase the current most effectively, what should you do? a. Reduce the width...

Homework Statement Consider the harmonic scillator potential perturbed by a small cubic term, so that V(x) = \frac{1}{2}m\omega^{2} (x^{2} - \frac{x^{3}}{a}) if a is large compared to the characteristic dimension (\hbar /m\omega)^{1/2}, the states will all me metastable, since there can be no...

Can someone give me either an explanation or a link to explain why tunneling cannot carry information greater than the speed of light? I understand why entanglement cannot, but this is not the same thing

Homework Statement A particle of mass m is incident on a planar barrier which we represent by a potential V(z)=\lambda\delta(x). If the energy of the particle is E, and the incident velocity makes an angle \theta with the z axis, what is the probability that the particle will penetrate the...

Homework Statement An electron of energy E = 2.10 eV is incident on a barrier of width L = 0.67 nm and height Vo = 3.10 eV What is the probability that the electron will pass through the barrier? Homework Equations I know that T=Ge^-2KL. K=2pi*sqrt((E-Uo)/1.505eVnm^2))...

How can we create a potential barrier? And how does it exactly acts as barrier in electron transfer?

From what I read, there is an extremely small probability of one going through a solid wall, according to QM. The chance is so small you might have wait a few lifetimes, or more of the universe to observe it. But how about going very shallowly into the wall? Let's say a few angstroms (Å)...

On pages 23 & 24 of the book Superforce by Paul Davies - The unusual occurances of electrons or other particles as they approach a barrier are described. I would like to know what devices are used in these experiments? What device shoots out electrons or other particles in a single stream...

The probability of finding the particle inside the wall is non-zero, What happen if we do find the particle is inside the wall, would that violate energy conservation? since total energy is smaller than the potential energy of the wall

Wave packets / the wave function is described as the probability density function of a particle, implying that the particle exists exactly at any 1 location at a time according to its associated wave function. This does not make sense to me on many levels, and it seems inconsistent with quantum...

Hi! I have a physics presentation tomorrow where I have to explain how a scanning tunneling microscope works. I also have to explain what quantum tunneling is and how it is used in a scanning tunneling microscope. I've done some research on the internet and I think I have a basic grasp of...

Homework Statement Alpha decay typically involves an alpha-particle of 5-6Mev. How can this be explained using quantum mechanics? Homework Equations The Attempt at a Solution I think I need to work out the potential barrier and then work out how much KE an alpha particle has...

Tunneling effect in Supercapacitors ? Hi everyone! This is my first post … so please bear with me! My question concerns the double layer developing within every supercpacitor / EDLC http://en.wikipedia.org/wiki/Electric_double-layer_capacitor" Considering the interface electrode –...

Homework Statement A 10eV electron is incident on a potential barrier of height 25eV and width 1nm. Estimate (order of magnitude) the probability that the electron will tunnel through the barrier, repeat your calculations for a barrier of 01.nm Homework Equations...

I've recently find out that is possible to describe tunneling effect by means of the instantons. Of course there are other methods to compute the transmission probability (WKB for example), but the real utility of this technique is that it can be applied in Quantum Field Theory (and also in...

Dear friends,how to calculate every transmission amplitude for each tunneling chanel in potential DeltaDirac(x- b*Sin(w*t))? Thanks for help...

Hi Supposing that someone had come up with the hypothese of electron tunneling before the discoveries and mathematical structure of QM... Solely within the Maxwell-Lorentz mathematical structure : 1) Could it have been proven that tunneling was impossible ?? 2) Could it...

assuming that the electron has an incident energy of 8eV and that the barrier is of height Vo=13eV and width L=5x10-10m calculate the probability that the electron will be able to tunnel through the barrier.Relevant equations= k = (sqrt(2m(V-E)) /h-answer (sqrt(2x9.1x10-31(13-8)x1.6x10-19)x2pi...

Homework Statement Hey, I found this interesting case in the tunneling problem. How do we calculate the transmission probability when the energy of the approaching particle is equal to the height of the potential barrier? I.e E=Vo. Homework Equations Same equations as in other...

I'm trying to wrap my brain around the notion of tunneling and am hoping somebody could be of assistance. I'm wondering about the history of the idea, why was the notion of quantum tunneling first created? (What prompted the idea?) Also, I'd like to find experiments that have shown that...

Homework Statement In a particular semiconductor device, electrons that are accelerated through a potential of 5 V attempt to tunnel through a barrier of width 0.8 nm and height 10 V. What fraction of the electrons are able to tunnel through the barrier if the potential is zero outside the...

When a particle tunnels through a finite barrier, does it spontaneously appear on the other side, or does it follow a path through the barrier? If it does the later then does it interact with the barrier? Thanks

I knew of this phenomena prior to , though prior to an e-mail amazon sent me I was unaware of what physicists called it. I have a question regarding the proton demonstration in this clip. Is it possible the electroweak force is acting on the 'tunneling' proton? If, as the commentator is...

I'm still in Intro Physics, and I'm a little perplexed by the concept of tunneling. An alpha particle escapes the nucleus by overcoming a potential energy barrier created by Coulombic repulsion with the protons of the nucleus, but this is a spontaneous process and does not require E input...

When considering an electron in a potential well, why is it possible for the electron to tunnel through a barrier of finite potential and not an infinite well. I can see the equations that disprove it (textbook) but i can't see any REASONS persay. Thanks.

Hi everyone, just wanting to know if anyone could help me out about particles tunnelling through square barriers with inital energy E<Vo. Does the energy of the particle change as it tunnels through the square barrier?

Wave functions that produce two lobes of electron probability on opposing sides of the core indicate that our point-like electron must tunnel through the nuclear core when the point charge moves to the opposing lobe. I don't understand what is the driving force for this process? Does this...

Homework Statement This isn't actually a homework question/problem, but a conceptual problem that I've been having regarding tunneling. Can someone please tell me what will happen to a particle's energy if a particle tunnels through some potential barrier, given that the particles energy is...

1. Homework Statement b). Find the kinetic energy K (sub t), the proton will have on the other side of the barrier if it tunnels through the barrier. c) Find the kinetic energy K (sub r), it will have if it reflects from the barrier. Variables: Transmission Coefficient (T) T= e^-2bL T...

1. Homework Statement b). Find the kinetic energy K (sub t), the proton will have on the other side of the barrier if it tunnels through the barrier. c) Find the kinetic energy K (sub r), it will have if it reflects from the barrier. Variables: Transmission Coefficient (T) T=...

Homework Statement Ok, maybe I'm slow at grasping this, but why is the potential energy U of an electron while it is tunneling through a 1 dimensional potential barrier of height V0 = V0? Homework Equations Schrodinger equation in 1D (using semiclassical approximation) The Attempt...

My understanding of the phenomenon: Occasionally a particle will tunnel through a solid barrier rather than bounce off. Theoretically the same is true for larger, more complex structures, it is just a matter of this happening to enough particles simultaneously. So, If you lean against a wall, as...

Homework Statement An electron approaches a potential barrier 10eV high and 0.5nm wide. If the electron has a 1%chance of tunneling through, what must be its energy? Homework Equations Transmission probability = [C/A]^2= [ 1 + (U^2 sinh^2(mu alpha))/(4E(U-E))]^-1 where...

Hi, I am trying to numerically calculate the tunneling probability for a wave function |psi> as a function of x. I have a double well potential. The wave function is initially in the left well. I do not know what exactly I have to find to show tunneling: the probability of being on the left well...