# What is Tunneling: Definition and 268 Discussions

In computer networks, a tunneling protocol is a communications protocol that allows for the movement of data from one network to another. It involves allowing private network communications to be sent across a public network (such as the Internet) through a process called encapsulation.
Because tunneling involves repackaging the traffic data into a different form, perhaps with encryption as standard, it can hide the nature of the traffic that is run through a tunnel.
The tunneling protocol works by using the data portion of a packet (the payload) to carry the packets that actually provide the service. Tunneling uses a layered protocol model such as those of the OSI or TCP/IP protocol suite, but usually violates the layering when using the payload to carry a service not normally provided by the network. Typically, the delivery protocol operates at an equal or higher level in the layered model than the payload protocol.

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1. ### A Flash memory and electron tunneling

Flash memory depends on tunneling in order to work—electrons have to tunnel through an oxide layer. Now, the wavelength of an electron is at most 24 pm. An atom is on the order of 100 nm wide, and the oxide layer must be at least several atoms thick. How can there be any significant tunneling?
2. ### A Tunneling from a True Vacuum to a False One: Is it Possible for the Higgs Field?

Could the Higgs field in a true vacuum tunnel to a false one? How much time would that process require?
3. ### Confused about quantum tunneling through 200V not eV

I have the equations to calculate transmission probability, my problem is that the barrier is given in Volts not electron volts. $$200V = e \cdot 200 eV = 3.2 \cdot 10^{-17} eV$$ I am not even sure if that's a correct conversion. But if it is then this "barrier" is extremly small and 99.999%...
4. ### Tunneling a VPN Within a VPN: Is It Possible?

Is it possible to put a vpn inside of another vpn, kind of like a tunnel in a tunnel? If so, how?
5. ### I Wavefunction properties tunneling effect

I am considering tunnel effect with a potential barrier of a certain height that is ##\neq 0## only for ##0 \le x \le a## . I write the Hamiltonian eigenfunctions outside the barrier as:## \psi_E(x)=\begin{cases} e^{ikx}+Ae^{-ikx} \quad \quad x \le0 \\ Ce^{ikx} \quad \quad x\ge a \\...
6. ### Quantum Tunneling to an infinite wall

I have the equations for all three regions but usually for region 3, which is Ce^ikx+De-ikx, the C term would be zero since there is no reflection, but with the infinite wall would it reflect? Would the whole wavefunction go to zero like when working with the infinite square wall? I'm stuck on...
7. ### A Metastable vacuum and tunneling

Hi all, I'm currently reading about instantons and theta vacua (section 93, p 572 of http://web.physics.ucsb.edu/~mark/ms-qft-DRAFT.pdf) Srednicki remarks in passing the following: What is a good way to "see" 93.5 is true? Is there a slightly simpler way than below which is my current...
8. ### I Superluminal Quantum tunneling without FTL messaging

I recently viewed a PBS "Space time" video The video references two articles of which one is paywalled while the other is not. https://iopscience.iop.org/article/10.1088/1367-2630/abb515/pdf https://www.nature.com/articles/s41586-020-2490-7?proof=tIn the discussion section of the free article...
9. ### I Could Light Absorption Be Linked to Quantum Tunneling?

Hi, I have just now started learning about quantum mechanics, and I have an Idea, which i am 99 percent sure is wrong, but i wanted to post it just in case. Okay, so I researched it a little and it turns out that the probability for a single particle to experience quantum tunneling is 0.1%...

I recently found out that for nuclear fusion to occur the temperature needs to be around 100 Million Kelvin and that the hottest part of the sun is only at 27 Million Kelvin. And that the reason nuclear fusion is occurring in the sun is because of quantum tunneling—allowing a very small fraction...
11. ### A Green's function for tunneling electrons between quantum dots

Good afternoon! I am writing with such a problem, I hope to find someone who could help me. I'm almost desperate! So, there is such a thing as the Braess paradox, this is a classic paradox for roads and power grids, and there is also such an article...
12. ### I Quantum Tunneling in an STM: ELI5 Requested

In an STM, you image the surface topography by tunnelling electrons from the metallic tip to the conductive surface, while measuring the current. I have worked with these instruments before and I never understood why does one need a quantum explanation for this. Wouldn't the electron jump to...
13. ### I Quantum Tunneling in the Sun and Conservation of Energy

Hi, In my textbook it says that if you consider the electrostatic repulsive barrier that protons in the Sun need to overcome in order to get into the range of the strong nuclear force to fuse together then it fails to fully account for the measured power output of the Sun. It says that the...
14. ### I Potential step and tunneling effect

We know that thanks to the tunnel effect, in the case of a finite potential step (V) and considering a stationary state, when a plane wave with energy E < V encounter the step the probabability that the wave-particle coming from -∞ (where potential is V=0) will be ≠ 0, in particular the wave...
15. ### What Prerequisites do I need in order to understand Quantum Tunneling?

Summary:: What tools like Calculus, Algebra, etc do I need to Understand how to Write a Quantum Tunneling Equation? I am New to QM however I feel I may have what it takes to do the Math, however, I am not privy to what the Prerequisites are that are needed to perform the...
16. ### I Pair production via Quantum Tunneling has negative Kinetic energy?

If we have a photon being converted to a positron-electron pair, but we lack enough energy for this to happen (hv<2Me*c^2) but the difference is smaller than the uncertainty amount, such that tunneling may be possible, would the resultant pair have net negative energy? Would tunneling even be...
17. ### B Quantum Tunneling different individual transmission probabilities

I have gone through all the videos on Youtube about Quantum Tunneling and became interested in it, so any helpful feedback would be appreciated. Do all the different individual transmission probabilities of electrons, protons, and such remain constant? May I ask what is the "formula" or...
18. ### Bohr-Sommerfeld, WKB, and current-biased Josephson junction

I've already found the turning points, in the case of the left turning point, the local minimum of the potential, ##\delta_{min}=1.11977## when evaluating for an arbitrary value of current ##J=0.9I_C##. The left turning point is therefore ##\delta_r=2.48243##. I know the Bohr-Sommerfeld...
19. ### I Is it possible to explain Quantum tunneling with the HUP?

I'm a student in South Korea(It is my first English question ever). I found descriptions of quantum tunneling explained by the uncertainty principle in Korea. There are two kinds of descriptions to explain quantum tunneling; position-momentum and time-energy uncertainty principle. First...
20. ### I Valley degeneracy in tunneling current

I'm trying to understand the valley degeneracy to calculate the tunneling current. Here is the equation of tunneling current.$$I_T=q\frac {g_sg_v} {L} \sum_{k} v_g(k)(f_v-f_c)T$$ ##g_v## is valley degeneracy. I thought it comes from the symmetry of structures, depending on a certain point in...
21. ### B Emission from a coated cathode and tunneling

I am wondering about an exercise exam question (it isn't homework): "at low temperatures (<2000 K), thermionic emission of a tungsten cathode depends on tunneling. By coating the tungsten with a suitable substance, the emission by tunneling can be greatly increased. Question: which two...
22. ### A Electron frequency components during orbital tunneling

For example, we have this two potencial wells approaching, the electron is confined in one. the final appearance will be like this: THEN, if we know a wave packet is formed by many frequencies, but in a potencial well there are just few frequencies allowed, energy levels, so let's say, one...
23. ### Quantum tunneling: T(E) graph for a potential barrier diagram

This is the V(x) diagrams and what I am thinking (really not sure though) is that for the first one you the energy has to reach V2 before it can start transmitting and the graph can take off from T=0, since there is an increase in energy potential that is V2. And as the energy increases, the...
24. ### B Tunneling through possible worlds

Forgive my poor lingo. As my bio states, I only have a complete degree in HS. Is it possible to quantum tunnel across possible worlds? If so, is there a hyper-dimensional plane where this would be made possible? And if so, how would you conceptualize or describe it? Information breakage...
25. ### A Scanning Tunneling Microscope I-V curve

I know that scanning tunneling microscopy (STM) I-V curve is exponential for a conducting sample. How would it look like if I had a semiconductor and a non-conductor sample?
26. ### I Understanding Electron Behavior in Quantum Tunneling through Dielectrics

When an electron leaves a conductor and tunnels through a thin dielectric; how does it behave in the space occupied by the dielectric? Does it behave like a ballistic electron traveling through vacuum? Is it instead that the electron never really occupies the space in the dielectric?
27. ### B Simulation Theory: Exploring QM Phenomena

Hi guys, something has been bugging me for a while now and I thought I’d just ask it here in the hope someone can explain it to me. Ever since Elon Musk brought it up, I’ve been thinking about the simulation theory (I know it’s not his original idea, it’s just the event that brought it to my...
28. ### I Tunneling through a finite potential barrier

I have 3 questions. After thinking about it I feel these questions may indicate that I have some misunderstanding in basic knowledge or some missed parts. 1. Why is the (time independent) wavefunction an exponential decay inside the potential barrier? I know the mathematical derivation, but I am...
29. ### I What basically is Klein tunneling ?

Recently, in my quantum physics classes i was introduced to the concept of tunneling of particle through a barrier potential and about transmission probability. Our instructor mentioned about something known as "Klein tunneling". Can somebody explain to me what is Klein tunneling and why...
30. ### A Tunneling Electron Energies

If we have a MIM device of Ti/Nb2O5/Ti at room temperature (300K), with a measured barrier height(s) of 0.0eV, the insulator thickness is say 2nm, and let's call the electron affinity of Nb2O5 4eV, and the Work function of Ti 4eV (for the sake of a simplified question), what is the average /...
31. ### I Source of energy for quantum tunneling of a particle

If a micro-particle tunnel through a barrier which has higher potential energy than the energy of the particle, then from where does the particle get the energy to cross that barrier?
32. ### Solving F-N Tunneling Equation Unit Match Problem

Hi, Everyone, Hope you are fine and doing great. I am new here and need to ask how can we match both sides of F-N tunneling equation in unit. I am attaching the equation, i am working on but i could not solve the unit match problem. if the left term has unit A/V2 then how can we solve 2nd...
33. ### I Concepts to understand Quantum Tunneling

What concepts should be cleared to better understand quantum tunneling?.
34. ### I Energy of an electron with Schrodinger's equation

Hello, I was trying to make a simple model of an electron tunneling through several potential barriers. The electron will flow through a conductor to a heterojunction of possibly semiconductor/oxide layers. I assume the electron is coming as a plane wave from the left with some energy E. We know...
35. ### B Quantum Tunneling: Reflection and Transmission Probabilities Explained

(P1 + P2)2 - 4P1P2 = (P1 - P2)2 (A - B = C) The reflection and transmission probabilities are R = C/A T = B/A Can one understand this from the first equation? ----[
36. ### I Quantum Tunneling Max Distance

I was assuming that it is possible to repeatedly measure an electron's position, but that it was not possible to know the result of the subsequent measurement because of the uncertainty principle. What I was wondering was whether the maximum distance between the two measurements is limited by...
37. S

### Can Macroscopic Objects Tunnel Through Walls According to Quantum Mechanics?

ok i read about that quantum mechanics article about how macroscopic objects have a extremely low probability of passing through a wall.Now i very clearly remember that 5-6 years back i have noticed my smiley sponge ball going into a place it cannot go to.Do you think it may have gone through...
38. ### Light-beam propagation across impassable barrier?

Hi all, (See attached image file) Two mutually coherent and collimated light beams intersect as shown, creating the stationary 'bright' and 'dark' fringes of fig.A. Suppose that, after the fringe pattern has formed, we insert a very thin (compared to the fringe-width) and (ideally) perfectly...
39. ### I (Conceptual) Infinity energy via quantum tunneling & Nuclear Fusion?

I was unsure whether or not to post this question here or in the Nuclear physics sub-section, but it's a relatively simple question: Given that quantum tunneling exists, would it be possible to produce infinite energy via repeated nuclear fusion reactions? Now given the second law of...
40. ### B Quantum tunneling - Questions about some pop-science claims

This might become a series of questions, but let me begin with the most essential one. According to QM/QFT, would it be true that there is a non-zero chance for an object on Earth to instantaneously tunnel to the moon for example? Like let's say a paper with a note on it. Could this paper...
41. ### I Quantum "tunneling" of sorts and QFT....

Hi all, Another naive question related a previous post (where the topic diverged somewhat). I'm wondering about the following thought experiment: Consider the field associated with a single electron. Now, confine the field to a region (volume) of radius R - that is, field values outside of R...
42. ### I Quantum Tunneling: Can it Cause Stable Systems To Transition?

I have noticed that quantum tunneling can cause unstable systems to suddenly transit to a stable state without going through its energy barrier. Can quantum tunneling cause stable systems, with as low energy as possible, to transit to other states?
43. ### How Does Quantum Tunneling Affect Electron Confinement in Potential Wells?

Homework Statement An electron with a total energy of Eo = 4.4 eV is in the potential well shown above. 1) Find the ratio of the wavelength in Region III to the wavelength in Region I. λ III / λI = 1.772) Given that the wave function of the electron vanishes at the left boundary of Region...
44. ### Mathematica Solving recurrence equations in QM tunneling example

I am ultimately trying to get Mathematica to solve some equations which are related to a tunnelling problem with an oscillating delta potential. I have the coefficients for absorption and emission: $$T_n = \frac{sm}{i\hbar^2} (T_{n-1} + T_{n+1})$$ T_q = \frac{sm}{2ik_q \hbar^2} (T_{q-1}...
45. ### B Exactly how quantum tunneling leads to a Big Bang?

In wikipedia says that in a big amount of time quantum tunneling can create a new Big Bang. EXACTLY, how this happens. https://en.wikipedia.org/wiki/Future_of_an_expanding_universe ("Beyond" part) *note: I'm in high school, but feel free to explain this with complicate process.
46. ### B Does right/left spin reverse in tunneling particles?

As I understand it, a relativistic reversal can occur in a Lorentz boost. A particle's forward angular momentum can become backward angular momentum, if the observer accelerates sufficiently. But the particle and its angular momentum are unchanged. The only change is in the observer’s frame...