Wave function Definition and 878 Threads

  1. C

    About the unit of Radial wave function R(r) of Hydrogen atom

    The 1s radial function of the wave function of H atom is: R10=2 a-3/2e-r/a ,where a = 5.29*10-11 meter but substituting a with its value,we will get R10 = 5.2*1015 *e(-1.89036*1010 r) and that is impossible if r=a and R(r)=1.9*1015 where is the problem ? What's more, the unit...
  2. S

    Exploring the Dimensions of Wave Functions

    dimensions of the one-dimensional wave function? is it [si]=L-1/2?
  3. R

    Finding V(x) of a given wave function?

    Homework Statement "A wave function is given by Aexp[(-x2)/(2L2)] with an energy of E = h-bar2/2mL2. Assuming this is a solution to the time-independent Schroedinger equation, a) What is V(x)? Make an accurate sketch of V vs. x with labeled axes b) What sort of classical potential has...
  4. T

    Wave Particle Duality and its relation to the Wave Function

    Ok so from my understanding, the wave particle duality of matter is simply the fact that matter sometimes behaves as a wave and sometimes behaves as a particle. Ok, but I wonder if this has anything to do with the wavefunction. The wave function gives us the probability spread of matter at any...
  5. Demon117

    Given a wave function at t=0, how do you find the wave function at time t?

    I am given the following: A spherically propogating shell contains N neutrons, which are all in the sate \psi(r,0)=4\piij_{1}(kr)(3/\sqrt{34}Y^{0}_{1}+5/\sqrt{34}Y^{-1}_{1}) at t = 0. How do we find \psi(r,t)? My attempt: I have a few thoughts; could you apply the...
  6. A

    Show that a wave function fits the Schrödinger's equation. (Harmonic oscillator)

    Homework Statement The wave function \psi_0 (x) = A e^{- \dfrac{x^2}{2L^2}} represents the ground-state of a harmonic oscillator. (a) Show that \psi_1 (x) = L \dfrac{d}{dx} \psi_0 (x) is also a solution of Schrödinger's equation. (b) What is the energy of this new state? (c) From a look at...
  7. W

    Schrodinger ground state wave function

    Homework Statement Find the ground state wave function for the 1-D particle in a box if V = 0 between x = -a/2 and x = a/2 and V = \infty Homework Equations I would guess -- Schrodinger's time-independent equation...
  8. R

    Wave function of spin 1/2 under parity

    Homework Statement How does the wave function of spin 1/2 change under parity? Homework Equations The Attempt at a Solution The behavior of the eigenfunctions of orbital angular momentum L is easily seen from their explicit form, namely spherical function Yml is multiplied by...
  9. B

    Does the Wave Function Predict the Most Likely Position of an Electron?

    Hi. I have a simple question- Does the wave function describe probability of finding a particle in a certain state upon collapse of the wave function?
  10. L

    Can the wave function collapse before being measured?

    N.B. I am not trying to send information back in time or generate infinite free energy (also I couldn't find how to delete the other thread but could a moderator please delete it for me) If you could send classical information signals faster than light, then according to relativity you could...
  11. A

    Can't The Collapse of The Wave Function be Explained Without MWI?

    Okay, so I am no expert in this field, but would like to acquaint myself more with quantum mechanics. As I understand it, the collapse of the wave function according to MWI only appears to occur, when really the observer is copied into as many different histories or worlds as there are possible...
  12. W

    What is the Probability of Finding an Electron in a Specific Angle in Hydrogen?

    Homework Statement Calculate the probability of finding the electron in a hydrogen within the angle \pm30\circ from the x-y plane.The hydrogen is in the (2,1,1) state. Homework Equations probability = \int\int\int\left|R_{2,1,1}\right|^{2} \left|Y^{1}_{1}\right|^{2} r^{2} sin(\theta) dr...
  13. H

    Does additivity apply to Fourier transform of the wave function

    I was wondering if this is correct: \phi(k-a)=\phi(k)-\phi(a) Where k=p/h (h bar that is) and a is some constant and \phi is the Fourier transform of a wave function (momentum function). I know that if I had some real formula for \phi I could just test this but the problem isn't like...
  14. Shackleford

    Radial Wave Function: Solving Equation for Normalized Radial Wave Function

    Radial Wave Function; Normalized Radial Wave Function 5. Is the brute-force method the only way to show the Equation is satisfied? By that I mean differentiating R20 once, twice, and substituting it in? I tried that earlier, but it was very nasty...
  15. S

    Zernike Polynomials Applied to Schrondinger's Equation

    Have Zernike Polynomials ever been applied to Schrondinger's Equation instead of psi? They're widely used in optics and seem to offer comparable positive traits. http://en.wikipedia.org/wiki/Zernike_polynomials http://wyant.optics.arizona.edu/zernikes/zernikes.htm
  16. R

    Collapsing a wave function by measurement

    Lets say we have a system in a 1D infinite potential well, prepared somehow with the wavefunction: (phi)=C(a-x)x. I understand that if I try to measure the system's energy, I will collapse the system to an eigen state ((psi)=Asin(n pi x/length)+Bcos(n pi x/length)), returning an eigen energy...
  17. J

    Help with understanding wave function

    Homework Statement Here are the screenshots of the textbook... http://i37.tinypic.com/nce7md.jpg http://i36.tinypic.com/8zpwew.jpg What I don't understand is the parameter (x - vt) I am confused by the picture. This is why I can't even ask a precise question, and rather I can only...
  18. Z

    How is the Wavefunction ψ(x) Related to the Probability Distribution P(x)?

    Homework Statement wave function of a particle in one dimension wave function of a particle in one dimension at time t=0 given by psi(x,0) = A(x^0.5)*(e^-ax) for x>0 or x=0 psi(x,0) = 0 for x<0 where x is in nms and a = 1nm where is the particle most likely to be found? or for...
  19. G

    Quantum Wave Function: Infinite Sheet of Charge & Pinhole

    Imagine an infinite, positive, uniform sheet of charge with a pinhole in it. A negative particle oscillates back and forth through the pinhole and in the +-x direction. The magnitude of the force on it is constant in time (although the force reverses direction when the particle passes through...
  20. B

    Stationary States and Spreading of Wave Function

    What I know: In stationary states the time dependence is factored out so it is of the form phi(q) * e^(-i omega t), thus in its appearance there is no wave function spread. However I recall from texts that wave packet spread is considered a universal phenomena in quantum mechanics, so I am...
  21. J

    Wave function on slope potential

    What are solutions to \psi''(x) = (a_0 + a_1 x)\psi(x) ? First idea I've had was that I could try some kind of perturbation with respect to the a_1 variable, so that \psi(x) = A_1e^{\sqrt{a_0}x} + A_2e^{-\sqrt{a_0}x} + \psi_1(x) would be an attempt. But I couldn't find...
  22. C

    Exploring Wave Function Collapse and the Double Slit Experiment

    I'm still wrestling with the whole uncertainty principal / wave function collapse idea. Obviously a basic building block of QM, I'm having a hard time understanding the real world evidence which supports these QM piles. 1. So from my understanding, the uncertainty principle tells us it is...
  23. B

    Spread of Wave Function Under Potential

    I have books (Quantum Theory by Bohm for example) with derivation of the spread of the wavefunction of a free particle in the Schrodinger equation. But does this spreading only happen as a free particle? What about under the general Schrodinger equation where there exist potentials that seem to...
  24. K

    What is a wave function and its collapse?

    I think that the wave function is the description of a particle's position at a point in time. But I'm not precisely sure what an eigenfunction is and how it is different. I know that certain eigenfunctions return certain values, and that even if you do not have a certain eigenfunction you can...
  25. M

    How does a wave function collapse?

    Hi. I've asked the question many times (as I'm sure many others have) why does the particle behave differently once it has been observed? Does that not mean it knows it has been observed? How does it know? The only answer I get is: "observing destroys the wave function" , but that doesn't...
  26. C

    Expectation Value For a Given Wave Function

    Homework Statement Find the expectation value of x (Find <x>) given the wave function: \psi(x)=[sqrt(m*alpha)/h_bar]e^[(-m*alpha*|x|)/(h_bar)^2] This wave function represents the single bound state for the delta-function potential. It's the solution to the shrodinger equation given the...
  27. L

    Solving an Ensemble of Particles Wave Function Problem

    b]1. Homework Statement [/b] I have the soloution to this question, but am confused as to what has been done between each step between lines 2,3,4. Can anyone explain how they have been simplified (espicially what happened to the operator) and what the value of the intergral is? I think I am...
  28. Z

    Normalization of wave function .

    I want to know how to normalize symmetric and anti-symmetric wave functions ??
  29. B

    Measuring Spin - wave function collapse

    It is my understanding that a measurement of S_z followed by a measurement of S_y will result in a particle which is in an eigenstate of S_y . But it appears that a measurement of say S_y followed by a measurement of S_x results in zero. I see this from a question in which I am asked to...
  30. V

    What are the properties of a normalized wave function?

    At time = 0 a particle is represented by the wave function \Psi(x,0) = \left\{ \begin{array}{ccc} A\frac{x}{a}, & if 0 \leq x \leq a, \\ A\frac{b-x}{b-a}, & if a \leq x \leq b, \\ 0, & otherwise, \end{array} \right where A, a, and b are constants. (a) Normalize \Psi (that is, find A, in...
  31. LarryS

    Wave Function: Real vs Imaginary Part

    Wave functions are, of course, almost always complex-valued. In all of the examples that I have seen (infinite square well, etc.), the real part of the wave function and the imaginary part of the wave function are basically the same function (except for a phase difference and possibly a sign...
  32. S

    How Does the Normalization of a Wave Function Work?

    hello i attached my question if i can get some help i think that there is another way to solve this problem
  33. C

    Description of Wave Function Collapse

    Hello, I'm new to Physics Forums, so I apologize if this question seems somewhat uninformed, but I have recently started studying quantum mechanics, and was curious about the idea of the wave function collapse, and how, from what I can tell, it seems to be approached completely independently...
  34. fluidistic

    Uniqueness of solution to the wave function

    Homework Statement Demonstrate that if u_1 and u_2 are solutions of the wave equation \frac{\partial ^2 u}{\partial t^2} - \triangle u=0 such that u_1 (0,x)=u_2(0,x), \partial _t u_1 (0,x)=\partial _t u_2(0,x) and such that the difference "tends to 0 at infinity" sufficiently quickly, then...
  35. T

    Wave function of hydrogen in 2s state

    Homework Statement Suppose that a hydrogen atom is in the 2s state. Taking r = a0, calculate value for \psi2s(a0) Homework Equations I did spherical harmonics for l=0 ml=0 times the radial wavefunction for n=2 l=0. Got the same thing as the solution manual attached but when I started...
  36. F

    Normalizing wave function, factor of 2 out

    Homework Statement Consider the wave function \Psi(x, t) = Ae^{-\lambda|x|}e^{-i\omega t} where A, \lambda and \omega are positive real constants. Normalize \PsiHomework Equations \int |\Psi(x, t)|^{2} dx = 1 |\Psi(x, t)|^{2} = \Psi^{*}\PsiThe Attempt at a Solution I have a model solution -...
  37. T

    Parity of wave function corresponding to even potential

    Homework Statement Using time independent 1D Shrodinger equation, show that if V(x) is even and Psi(x) is a solution, Psi(-x) is also solution. Then, assume Psi(-x) and Psi(x) differ only by a constant, show that the constant is either +1 or -1. Homework Equations The Attempt at a...
  38. G

    What is the correct A value for normalizing the given wave function?

    Homework Statement The function \Psi(r) = A(2-{Zr\over a})e^-{Zr\over 2a} gives the form of the quantum mechanical wavefunction representing the electron in a hydrogen-like atom of atomic number Z when the electron is in its first allowed spherically symmetric excited state. Here r...
  39. L

    Is This Wave Function Normalization Correct?

    Homework Statement http://www.ph.qmul.ac.uk/~phy319/problems/problems1.doc" Question 2)b The Attempt at a Solution http://img685.imageshack.us/img685/9033/p270210111001.jpg Is this correct? Thanks!
  40. H

    Wave Function - Normalisation & Calculation of Expectation Values

    Homework Statement i. Confirming the wavefunction is normalised ii. Calculating the expectation values: <\hat{x}> , <\hat{x^{2}}> , <\hat{p}> , <\hat{p^{2}}> as a function of \sigma iii. Interpreting the results in regards to Heisenberg's uncertainty relation. Homework Equations...
  41. I

    Is My Normalized Wave Function Accurate?

    Hi, I built a small program to show that the normalized hydrogen wave function (ground state) integrates to unity, as expected. But I got an absurd value: 4.6x10^19 instead. I spanned a big volume (30 Bohr's radius) calculating and summing the product dr*dphi*dtheta * psi * psi. Worse yet...
  42. H

    Why are even and odd functions orthogonal in quantum mechanics?

    shai n and shai m are mutually orthogonal ...where n and m can any numerical value...but i can't imagine it how they can be perpendicular to one another ... (to me the worst thing is to think shai4 and shai100 are perpendicular) and what is the advantage or reason of it...can anyone help me to...
  43. S

    Solving the Wave Function: Find Ea, q, and Time?

    Homework Statement http://img29.imageshack.us/img29/5236/phst.jpg Homework Equations http://img25.imageshack.us/img25/8815/11203939.jpg I need to find the equation for the question. The Attempt at a Solution a) A bunch of waves/wave functions, that have phases/amplitudes that interfere...
  44. nomadreid

    Measurement effect upon wave function

    If I understand correctly, a measurement affects the wave function only at the moment of measurement. In other words, if one were able to compare two wave functions, one when there were measurements, and one in which there were no measurements, the only difference would be at the meager set of...
  45. C

    How Do You Calculate the Position of a Neutron Using Wave Functions?

    Hello I need to calculate <x> (x is the location of neutron) and the state is and the integral is: Can I move the x to be near the integral symbol? and how to I multiply the matrices? And is this true: Can I move the psi to be near the psi*? And psi*x psi =psi^2=1 right? thanks
  46. F

    Question on the Collapse of the wave function?

    Fact 1.From relativity we have come to view the universe as 4 Dimensional. That is 3 Dimensions of space and 1 of time. As such I have the following questions. Questions 1. Given the universe is 4D, does it not follow that all objects within the universe is 4D? 2. If 1 is true, does it mean...
  47. P

    Basis Transformation for Wave Function

    Homework Statement It's not a homework problem. I'm reading my textbook (Sakurai's Modern QM), and I'm not sure about a step (eq 3.6.6 through 3.6.8). Here it is: We start with a wave function that's been rotated: \langle x' + y' \delta \phi, y' - x' \delta \phi, z' | \alpha \rangle Now...
  48. B

    How to Find Instantaneous Displacement in a Sinusoidal Wave?

    Homework Statement A sinusoidal sound wave is described by the displacement wave function s(x,t)=(2.00 μm)cos⁡[(15.7 m^(-1) )x-(858 s^(-1) )t] b) Determine the instantaneous displacement from equilibrium of the elements of air at the position x = 0.050 m at t = 3.00 ms Homework...
  49. S

    Real and imaginary parts of wave function

    A very general question: What do the real and imaginary parts of a wave function correspond to physically? Cheers
  50. C

    Confirming Symmetric & Antisymmetric Solutions for Wave Function

    Homework Statement Hello, Can you confirm that what I wrote is correct for the given potential? https://www.physicsforums.com/attachment.php?attachmentid=22309&stc=1&d=1260118852 Now I wrote the term for the wave funcation and for the given symetric potential , the functions of the...
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