Heisenberg Definition and 290 Threads

\Delta x \Delta p \geq \frac{\hbar}{2}. Say I want to measure the best I can the position of an electron, in detriment of its momentum (i.e. velocity since I assume that I know its mass quite well). When \Delta x \to 0, \Delta p should tend to +\infty but there's the c limit so that I can't...

I was trying to follow http://www.youtube.com/watch?v=dCua1R9VIiQ&p=EFD655A9E0B979B7&playnext=1&index=54" lecture at the 4:15 mark but am having a little difficulty. In particular, why doesn't he have to take the commutator of all four of the terms you get when you square (p-eA). Is he using...

Homework Statement hi i am new to this principle if i was to calculate the Heisenberg uncertainty of a nuclei of radius r would i take my delta x as r or as the diameter of the nuclei thanks Homework Equations The Attempt at a Solution

Hi, this is my question: suppose that at time t' our system is in the state | \psi(t')\rangle The probability for the system to be in the state | \phi\rangle at the time t'' is the norm of \langle \phi| \psi(t'')\rangle This in the Schrodinger picture. But how i can write the same thing in...

Please tell me where my understanding of the Heisenberg and/or the Schrodinger picture falls apart. -Schrodinger says the state vector of a system changes with time according to a unitary operator that doesn't change with time. -Hesienberg says the state vector of a system doesn't change...

Hello, I'm studying the Heisenberg Model. Given the Hamiltonian H = - 2 \frac{J}{\hbar^2} \vec{S}_1 \vec{S}_2 with \begin{equation} \vec{S} = \frac{\hbar}{2} \; \left( \begin{array}{ccc} \sigma_x \\ \sigma_y \\ \sigma_z \end{array} \right) \end{equation} \sigma_{x,y,z} \quad...

In Six Easy Pieces: Fundamentals of Physics by Feynman, the claim is made that the reason why electrons don't just collide “ontop” of the nucleus is due to the Heisenberg uncertainty principle. This perplexes me greatly; it sounds wrong to me. The moon and the Earth do not collide because...

There are two basic facts that I have difficulty reconciling: (a) the magnetic and electrical components make up a complementary pair of variables (b) Maxwell's equations describe the magnetic component in terms of the electrical one and vice-versa My question is definitely not original...

From what I understand, the Heisenberg Uncertainty Principle means that we can never know the position and velocity of a particle at the same time, as the measurement of one necessarily affects the measurement of the other. Great. I understand that theory, and it makes perfect sense. But what...

I got in an argument with my dad over the weekend. Is the Heisenberg uncertainty principle a result of technological limitation or a basic premise in quantum mechanics? Basically is the information fundamentally "unknowable" or simply unmeasurable?

Heisenberg Uncertainty, Need Some Clarification. TIME SESITIVE, HELP! Homework Statement Use the Heisenberg uncertainty principle to calculate Deltax for a ball (mass = 100 g, diameter = 6.65 cm) with Deltav = 0.645 m/s. Homework Equations PX = h/(4*3.14) The Attempt at a Solution...

Homework Statement Starting from one of the more familiar Heisenberg Uncertainty Relations, derive the Uncertainty Relation involving angular momentum and angular displacement and explain its significance. Homework Equations The relevant uncertainty relationship is that between...

Homework Statement 18. A ball of mass 50 g moves with a speed of 30 m/s. If its speed is measured to an accuracy of 0.1%, what is the minimum uncertainty in its position? 19. A proton has a kinetic energy of 1.0 MeV. If its momentum is measured with an uncertainty of 5.0%, what is the...

After about 20 years I'm going back and brushing up on quantum. I am confused about an electron in an s-orbital having zero angular momentum as well as how angular momentum in general relates to Heisenberg uncertainty. I probably have a few misconceptions as well as missing some key pieces...

Scientists have reportedly been able to transport atoms and molecules as much as 1800 feet. Could the same be done for humans, or would the Heisenberg Uncertainty Principle ultimately make it impossible?

Hi All, I understand that it is impossible for man to know both the position and momentum of a particle with arbitrary accuracy. This is a result of the physics of photons which are necessary to observe an object. Now although man cannot know the exact position and momentum...

Is the Heisenberg Uncertainty Principle as statement about the state of a particle or only a statement about what can be observed about a particle?

a 1.0 micrometer diameter dust particles (mass 1.0x10^-15kg) in a vacuum chamber pass through a hole (diameter assumed to be exactly that of particle) onto a detection plate 1.0m below. By how much does the diameter of the circle increase Homework Equations This is clearly a Heisenberg...

What is approximation of the chaotic phases for Heisenberg feromagnet in low temperatures?

Hi, I have a problem with the uncertainty principle. The way I understand it, Heisenberg used ideas from classical mechanics and the concept of wave/particle duality to show a contradiction in classical mechanics, i.e. that it is impossible to know with exact precision both the momentum and...

I read that the Heisenberg uncertainty principle arises for stuff like electrons simply because the observer affects the observed . That is,because photons (or what ever the observer uses to detect the position) will affect the trajectory of the particle... That doesn't make much sense to...

So, I'm doing some undergraduate research in quantum spin systems, looking at the ground states of the Heisenberg Hamiltonian, H=\sum{J_{ij}\textbf{S}_{i}\textbf{S}_{j}}. But I think I have a critical misunderstanding of some fundamental quantum mechanics concepts. (I'm a math major, only had...

Sorry about not using symbols but I haven't learned how to do that yet. 1. Homework Statement A woman is on a ladder of height H. She drops small rocks of mass m toward a point target on the floor. Show that according to the Heisenberg Uncertainty Principle, the average miss distance...

Hi everybody! I'm looking for the critical exponent ν (i.e. the one of the correlation length) of the Heisenberg (i.e. equal coupling in all directions) antiferromagnetic spin-1/2 model in 1D... Furthermore, do you know to which universality class it belongs? Is it true that it's the...

if we can find a 'soliton' solution for Nonlinear Schroedinguer equation , then does this imply that Uncertainty principle is false ?? since a soliton is a localized wave packet then i can find the position of the soliton and its momentum so apparently i have violated uncertainty.

Hello all I have a question concerning The Heisenberg Uncertainty Principle. The principle mathematically looks like this- \Delta x\Delta p \geq \hbar/2 The principle states that you can not measure more than two quantities simultaneously. If you know a...

hi folks, last problem I can't get done here. I usually have a good idea of where to start, what to use. but I'm a bit flummoxed. Homework Statement A neutron, of mass m = 1.67 10-27 kg, is localized inside a carbon nucleus, of radius 7.0 fm (1 fm 10-15 m). Use the uncertainty relations...

Homework Statement Sort of stuck deriving the Klein-Gordon equation from Heisenberg equation of motion \dot{\varphi} = i [H, \varphi ] Homework Equations \dot{\varphi} = \frac{\partial\varphi}{\partial t} H = \int d^3x \mathcal{H} \Pi (x) = \dot{\varphi}(x) \mathcal{H} = \Pi...

Homework Statement Using the uncertainty relation for momentum and position, show that the quantum-mechanical uncertainty in the position of a particle at temperture T is \Delta x~\sqrt{\frac{h^{2}}{4mkT}} where T is the temperature and k is the Boltzmann's constant. Homework Equations...

Just reading about how if an operator commutes with the Hamiltonian of the system then its corresponding obserable will be a conserved quantity. my notes say that if \hat{L} commutes with the hamiltonian then the angular momentum will be conserved. this kind of makes sense but surely it's...

Homework Statement Particles pass through a single slit of width 0.2 mm in a diffraction setup. The de Broglie wavelength of each particle is 633 nm. After the particles pass through the slit, they spread out over a range of angles. Use the Heisenberg uncertainty principle to determine the...

HUP states that "certain physical quantities, like the position and momentum, cannot both have precise values at the same time. The narrower the probability distribution for one, the wider it is for the other." (Wikipedia) I am not a physicist, but I have been pondering this question: In this...

Wich are the differences between the theorem of ehrenfest and the Heisenberg's rappresentation of quantum mechanics?

Can anyone prove, in layman terms (or as close an approximation to layman terms as is possible), why exactly ∆p ∆x ≥ h-bar /2 ? Please explain every step in the deduction, and not just with formulae. I can't just take something for granted. Thanks in advance.

Hello there!I have a small question regarding Heisenberg uncertainty relationship. If one sets up a double slit experiment and one looks through which hole the electron passes, so it acts as a particle and you know exactly where it is. If immediately after that slit, you place some sort of...

Any guidance towards designing an expiriement/lab/activity related to Heisenberg Uncertainty Principle? It doesn't have to be complex or anything, just something at least related to the HUP. I can't think of anything, my understanding is that this principle only really applies at the quantum...

Today I was assigned a question (that is due tomorrow) and I currenlty have very little idea how to solve it... Any help to get me started here would be greatly appreciated. 1. Use the uncertainty principle to estimate the uncertainty in energy of a proton confined to a nucleus 1.0 x 10^-14m in...

Hello everyone. I've been reading the forums for a while so decided to register hoping to increase my learning curve in my physics and mathematics classes. I started back to college last year after a 5 year break since I had quit college. I was previously a music education major, so when I...

Hello all, I have gathered that the orbit of an electron cannot be calculated due to the uncertainty principal which states that position becomes uncertain when momentum is measured and vice versa. From this I understand that an orbit is not possible for an electron, hence the term...

I've a problem to understand the Ising model and the Heisenberg model. Can anyone explain to me what is the different between ising model and the Heisenberg model?

A measurement establishes the position of a proton with an accuracy of ±1.00 x 10 ^ -11 m. Find the uncertainty in the proton's position 1.00s later. DE Dt ≥ h / 4 ∏ Dx Dp ≥ h / 4 ∏ using DE Dt ≥ h / 4 ∏ DE = 5.276*10^-35 J where t = 1.00s I am stuck as...

In the Heisenberg picture, we move the time dependence away from the states and incorporate them in the operators. That is, if we write the time dependent state in the Schrodinger picture as |\Psi(t)\rangle=e^{-iHt}|\Psi\rangle, then an expectation value for an operator Q at time t, which we...

A fundamental quantity that we calculate with QM is \langle \Phi|\Psi\rangle-- the probability amplitude for observing a system to be in state |\Phi\rangle given that it is in state |\Psi\rangle. In the Schrodinger picture the states are time-dependent and we can ask, "What is the probability...

I was reading a book and came upon these lines: Based on these lines alone, what would you make of the author's grasp on the principle? If you didn't know what the HUP was, what impression would you get?

Did I do this right? An exercise in a book where my answer came out opposite from the author's. [PLAIN]"camoo.freeshell.org/22.9.pdf"[/URL] Laura

A block is at rest. The block is macroscopic so we can see that it is at rest and where it is, i.e. we know its position with certainty. Suppose we use the Heisenberg Uncertainty Principle to estimate the position uncertainty Δ x. Consider the following argument: Since the engine is at rest...

[SOLVED] Heisenberg and energy of an electron in a potential well Homework Statement An electron is confined within a one dimensional potential well that measures 1 nm. using the uncertainty principle, estimate the order of magnitude for the ground state energy of the electron in the well in...

A student is examining a bacterium under the microscope. The bacterial cell has a mass of 0.200 (a femtogram is 10^-15) and is swimming at 4.00 microns per second, with an uncertainty in the speed of 5.00%. E.coli bacterial cells are around 1 micron, or 10^-6 meters in length. The student is...

Might there be a similarity between Dyson's equation and Heisenberg equation? (It's just a feeling, nothing based on arguments.) Both describe how a system (density matrix or Green's function) behaves in time. Both require knowledge of the intial system at time t=0 and the potential acting on...

[SOLVED] Heisenberg Uncertainty Principle question Suppose that the x-compenent of the velocity of a 3.0 x 10^-4 kg mass is measured to an accuracy of plus or minus 10^-6 m/s. What then is the limit of the accuracy with which we can locate the particle along the x-axis? Any help on where to...