Tunneling Definition and 268 Threads

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...

Suppose someone drops a clock and it tunnels through the Earth. What time will have elapsed according to the clock when it emerges on the other side of the Earth?

Homework Statement I am to show that quantum effects are negligible in: (i) The diffraction of a tennis ball of mass m=0.1 kg moving at a speed of 0.5 m/s by a window of size 1X1.5 m^2 (ii)The tunneling probability for a marble of mass m=5 g moving at a speed of 10 cm/s against a...

in zener tunneling phenomena, are the carriers locally generated or non-locally generated? i.e, should we assume the process as though it were generation of holes in the valence band and electrons in the conduction band? i hope someone could shed some physics on this concept. thanks.

Homework Statement When an electron has tunnelled through a potential barrier it's wavefunction is described by a plane wave traveling in the positive x direction. In this region the probability density is constant. I am trying to explain why it is constant but can't find any info in books or...

Homework Statement By using the graph attached, Why high energy alpha particles are emitted by alpha-emitters of short wavelength? Homework Equations Transmission Coefficient Equation : T=exp(-2kd) The Attempt at a Solution Ain't really sure. Can't really figure out why is...

An electron and proton with the same energy E approch a potential barrier whose height V is greater than E. Do they have the same probabilty of getting through? If not, which has a greater probability? Why is that true? So if the electron and proton have the same energy, that means that the...

Homework Statement There's two parts. Part A) Find the Probability than an electron will tunnel through a barrier if energy is 0.1 ev less than height of the barrier. Barrier is 1nm. Part B) Find tunneling probability if the barrier is widened to 3 nm.Homework Equations I believe relevant...

correct me if I am wrong, but from what I remember, standard tunneling occurs because of the Heisenberg uncertainty principle. There is some known error in the position of a particle (probably a 3d gaussian distribution centered on the mean and with a standard deviation equal to this error...

Hello, I am trying to learn something about how experimental physics is done. I am very new at it and am looking for experienced guidance. A friend of mine (zapperz) suggested that a good way to measure the effect of a magnetic field on electrons in the tunneling state is to have the...

Just wondering in regards to the potential step, what exactly is it in term of physical substance? If its made up of some or any sort of matter, wouldn't the tunneling be effected by the molecular structure and the distance/gap between the particles?

I am interested in measuring the effects of a magnetic field on an electron in a tunneling state. I know very little about solid state and I have very little experimental experience. In order to learn what is required to perform such an experiment, I thought I would pose my question here...

Hello, I know that electrons will be deflected if they move in a magnetic field. I was wondering if tunneling electrons would be deflected in the opposite direction? plxmny

Gentlemen, The website [PLAIN]www.altair.org[/URL] describes how to create a homebuilt quantum tunneling experiment which I would like to try. It requires the use of a Gunnplexer. If I search for that term, all references to that term seem presuppose more knowledge that I have. Can...

I am working on a project involving a scanning tunneling microscope, and to move atoms i need an untra high vacuum chamber. Any info you have on UHV or STM would be immensly appreciated.:rolleyes: Thanks

Homework Statement We consider a simple model of alpha decay. Imagine an alpha particle moving around inside a nucleus. When the alpha bounces against the surface of the nucleus, it meets a barrier caused by the attractive nuclear force. The dimensions of this barrier vary a lot from one...

Hi, this is my first post here so apologies for any faux-pas I inadvertly do. Anyways, to the subject at hand. Evanescent Wave Coupling -> abbrv. -> EWC Can someone explain to me evanescent (decaying) waves work? I have been reading a wiki article about EWC, and it made many...

I have seen the mathematical proof of how can a particle tunnel through a barrier of higher potential energy but I was unable to understand what happens to the particle during its motion in the barrier. Can you help me? Can this be one of the probable mechanism of teleportation on which I can...

I am a freshman high school student working on a scanning tunneling microscope for a science fair project. I need to build a vacuum for bottom up capabilities. If anyone can help with the STM or the vacuum it would be greatly appreciated.:rolleyes:

Say I have a particle with a kinetic energy of 5 (in some units). And I have a potential barrier of 10 between 0<x<1 (again, in ome unit system), and 0 elsewhere. According to quantum theory, the partcile may be found between 0 and 1. And in this region, if the energy is conserved (5 = T + 10)...

Evolutionary "tunneling" Consider a specific organism. It initially undergoes a genetic change which is nonbeneficial - even detrimental - to several generations. That intermediary state, however, eventually leads (synergistically with a secondary mutation) to an overall postive adaptation...

When something tunnels, is it just because of the fact that the wavefunction just decided to randomly pick a place that would be disallowed by classical physics? or is there more to it?

I am trying to understand the PBS NOVA ‘The Ghost Particle’ shown Tuesday 28 February 2006. http://www.pbs.org/wgbh/nova/neutrino/ Question 1 - When neutrinos pass through the Earth interacting in a statistically predictable manner, is this an example of quantum tunneling conforming to a...

Hi, for my integration class I am building a scanning tunnelling microscope (STM). I found some interesting designs and I choose the cheapest one (students are poor) witch uses a unimorph disk. Here is the STM design I plan to build: http://www.geocities.com/spm_stm/". For my class I need to...

Hi, for my integration class I am building a scanning tunnelling microscope (STM). I found some interesting designs and I choose the cheapest one (students are poor) witch uses a unimorph disk. The circuits are not that hard to build but I also need to understand them. I have some knowledge in...

Supposed we have a metal sandwitched between two thin dielectrics. If i contact an electrical voltage on the dielectric, there will be tunneling current due to electron tunneling from the metal across the dielectric. i could attempt to calculate this current from a semiclassical approach using...

Quantum tunneling and other experiments(for experimental experts)... Please read on this website: http://en.wikipedia.org/wiki/Faster-than-light So,what does it mean-does it mean we can start to hope for traveling faster than light? I also found,what some others wrote about this,from other...

I can't work out what I am doing wrong in this question. Anyways, here it is: A 3.0 MeV proton is incident on a potential energy barrier of thickness 10fm and height 10 MeV. What is the transmission coefficient T. And here is what I have tried: T=e^(-2bL) b=\sqrt{\frac{8\pi^2m(U_b-E)}{h^2}}...

Can the phenomenon of quantum tunneling be explained? Any theory that can account for it? Or is it just empirical? Would someone kindly answer my questions? o:)

in barrier tunneling, if voltage is applied between two different materials, for eg Cu and Al and then the polarity is inversed, will there be any difference in the tunneling current?