Hi,
In Griffiths QM, it is claimed that to solve the Schrodinger Equation, we take the solution wavefunction \Psi(x,t) to be of a seperable form \psi(x)\phi(t).
He then says that a superposition of these seperable forms can always give us the general solution. Can someone help me prove that...
Note : I am not sure this is the right section for posting it , but from the rules section i saw that this section can be used for homework related queries and independent study .
Homework Statement
Understanding schrodinger equation . i want to understand the solutions of this equation and...
The general evolution of a ket |\psi\rangle is according to
-i\hbar\frac{d}{dt}|\psi\rangle=H|\psi\rangle
without specifying a representation.
From this equation, how can you simply get a equation in a certain representation F as below:
-i\hbar\frac{\partial}{\partial t}\langle...
Hello,
I'm reading Griffiths' introduction to elementary particles and he seems to claim that the Schrödinger equation can be seen as a non-relativistic limit of the Dirac equation. I was wondering how one could deduce this, e.g. how do we go from
\mathcal L = \bar{\psi} \left( i \gamma^\mu...
Ok, I understand the schrodinger equation for the most part, the thing is though, I don't understand what ∂ means...
In the equation:(∂^2ψ/∂x^2)+8(pi)m/h^2(E-V)ψ=0
It pops up two times. The rest of the equation is kinda self explanatory, but I don't know what on Earth ∂ means
please, tell me...
The Schrodinger equation solved for the hydrogen atom gave good agreement with spectral lines, except for line doublets.
To account for these electron spin theory was grafted onto the theory, despite the problem of electron being a point particle.
In 1928 Dirac gives his different answer...
The normalization condition is:
∫|ψ|^{2}d^{3}r=1
In spherical coordinates:
d^{3}r=r^{2}sinθdrdθd\phi
Separating variables:
∫|ψ|^{2}r^{2}sinθdrdθd\phi=∫|R|^{2}r^{2}dr∫|Y|^{2}sinθdθd\phi=1
The next step is the part I don't understand. It says:
∫^{∞}_{0}|R|^{2}r^{2}dr=1 and...
My DE is
\frac{h^2}{2m} \frac{d^2\psi}{dx^2} + \left(E - \frac{Ae^{-ax}}{x} \right) \psi = 0
where h, m, A < 0 and a and E are constants. I need to construct the following series solution (using the larger root of my indicial equation):
\psi(x) = a_0 \left[x + \frac{Am}{h^2}x^2 +...
How can i solve Schrodinger equation in 3dimension i want to know how can i deduce every equation ? and how can i find equation of spherical harmonic and radial equation ?
i need to understand this proof
Hi all,
In class I've recently been taught the schrodinger equation and about spin(couple weeks apart). My questions are-
1. In laymans terms, what exactly does the S-eqn mean? What I have taken it to be so far, is an equation that determines the probability of the position of an e- in...
Homework Statement
Derive the Non-Linear Schrödinger from calculus of variationsHomework Equations
Lagrangian Density \mathcal{L} = \text{Im}(u^*\partial_t u)+|\partial_x u|^2 -1/2|u|^4
The functional to be extreme: J = \int\limits_{t_1}^{t_2}\int\limits_{-\infty}^{\infty}\...
At the moment I am studying the Schrodinger equation using this resource.
In a 1D solution (sec 3.1 in the paper) they show that a wave function can be expressed as
\Psi(x,t)=\sqrt{2}e^{-iE_{n_x}t}\sin (n_x\pi x)
where n_x is the quantum number. And they show the real part of the solution in...
Schrodinger and Infinite Square Well... hell
Homework Statement
Show that Schrodinger Equation: \frac{d^{2}\psi(x)}{dx^{2}}+k^{2}\psi(x)=0 has the solution \psi(x)=A\sin(kx)
Homework Equations
k=\frac{\sqrt{2mE_{tot}-E_{pot}}}{\hbar}
The Attempt at a Solution
I already know that...
Why "i" in Schrodinger Equation
Schrodinger Equation is "i*h*dphi/dt=H*phi"
That is to say that the change in the state is proportional to a linear tranformation of the actual state (I understood the logic behind that), H is hermitian and that means that its eingenvalues are real (right?)...
Homework Statement
By substituting the wave function \psi (x) = Ax{e^{ - bx}} into the Schoedinger equation for a 1-D atom, show that a solution can be obtained for b = 1/{a_0}, where {a_0} is the Bohr radius.
Homework Equations
- \frac{{{\hbar ^2}}}{{2m}}\frac{{{d^2}\psi...
Homework Statement
Hello!
I am currently stuck with a time independent Schrodinger equation where the potential "V(x)" is hyperbolic in nature. I was wondering if anyone could give me a hint as to how I should approach this problem in order to get an analytical solution (without using...
Hi,
I'm doing a homework problem in my modern physics class and I'm stuck at a point. The question is "Show that the radial probability density of the 1s level in hydrogen has
its maximum value at r = a0, where a0 is the Bohr radius"
I know that the radial schrodinger equation will...
hi all please help me... I'm learning schrodinger equation of a particle in a 1-dimensional box. I read a quantum mechanics book written by A. C Phillips. the wavefuction is
ψ (x,t)= N sin (kx) e-iEt/hbar
but when I compared to what I read from a modern physics book written by Beisser. the...
Homework Statement
the question as well as the hint is shown in the 3 attachments
Homework Equations
The Attempt at a Solution
i know how to normalize an equation, however i do not understand what the hint is saying, or how to do these integrals, any guidance would be greatly...
Homework Statement
Proton traveling along the x-axis approaches a potential barrier at x = 0
Height of potential barrier - U0 = 20eV
Proton Velocity = 44km/s = 44,000m/s
Asked to show that the solution to the one dimensional time independent Schrödinger equation is
\psi(x) = A sin...
Homework Statement
Consider the infinite well, a particle with mass m in the potential
V(x) =
\begin{cases}
0, & 0 < x < a,\\
\infty, & \text{otherwise,}
\end{cases},
At t = 0 the particle is in the state:
\Psi(x,0) = B \left[\sin{\left(\frac{l \pi}{a}x\right)} +...
Consider the potential
V(x) =
\begin{cases}
0, & x < -a & (I) \\
+W, & -a < x < a & (II) \\
0, & x > a & (III)
\end{cases}
for a particle coming in from the left (-\infty) with energy E (0 < E < W). Give the solution to the Schrodinger equation for I, II and III and use these to...
Hello,
I can't seem to find a reference formulating the Schrödinger equation as a set of two differential equations in terms of the modulus |\psi| and the phase S instead as one diff. eq. in terms of the complex wavefunction \psi = |\psi|e^{i S}.
Can anyone show me the way?
I have the following Schrodinger equation:
i* (h-bar) * partial derivative of ψ(x,t) w.r.t time
=
[(m*w^2 / 2) * x^2 * ψ(x,t) ] - (1/2m) * (h-bar)^2 * (laplacian of ψ(x,t))]
m>0 is the mass
w is a positive constant
Assume that the ground state...
Greetings everyone,
I haven’t done any quantum in a while, and was reviewing my textbook, Griffiths Ed. 1. The form of the Schrodinger equation I’m using is:
i\hbar\partial\Psi/\partialt = -\hbar2/2m * \partial2\Psi/\partialx2 + V\Psi
The book says if V is a function of x only, then the...
not all functions are wavefunctions. For functions to be wavefunctions they have to obey a series of "rules". Now, my question is:
there are many functions, which obey these rules which aren't eigenfunctions of the hamiltonian, thereby meaning that they don't obey the Schrodinger Equation...
Suppose you've got a function \psi(t) that satisfies i\dot \psi = H \psi for some self-adjoint Hamiltonian H. I'd like to apply the fundamental theorem of calculus to this guy and write something like
\psi(t) - \psi(0) = \int_0^t \psi'(s)ds.
Can I do this, given only the very bare...
I'm an A-level student (I don't know what the US equivalent is sorry, I'm not an undergraduate is what I'm saying), and I've independently done a project on wave functions for a few simple stationary systems; particle in a box and quantum harmonic oscillator are the ones I focused on in the end...
This is a pretty trivial question, but how is the Schrodinger equation written out in full, time dependency and all in Dirac notation? I'm interested in this from a purely aesthetic point of view but I'm also a bit confused as to what the bras and the kets really are.
Homework Statement
Given a wire with length a and square base b x b (where a >> b), show that the first 1700 (approximately) levels of the electron in the wire are identical for the one dimensional box, when a = 1m and b = 1mm.
Homework Equations
I know that the allowed energies of...
Homework Statement
What are the similarities and differences between the quantization of angular momentum in the Schrodinger theory and in the Bohr model?
Homework Equations
?
The Attempt at a Solution
Similarities:
-In both theories, the principal quantum #, n, determines the...
How do you find an expression for the energy eigenvalues from the TISE (Time Indipendant Schrodinger Equation) for a given potential.
e.g. why is:
E = (N + 1) hbar*omega
an expression for the energy eigenvalues for a potential of:
V = 1/2*m*omega2x2
??
I really have no idea where to start...
Hi, i am beginning elementary Quantum Mechanics as my course. While studying one question arise in my mind :
In the solution of Schrodinger wave equation there are two parts.
ψ=A*exp(jKx) + B*exp(-jkx). (for confined electron)
But when dealing with free electron the solution is of...
Homework Statement
In David Griffiths Introduction to Quantum Mechanics (2nd ed.), page 32 he normalizes a time independent wave function to get the coefficient A. He dropped the sine part of the integration with no explanation. What is the justification.
Homework Equations
The time...
Homework Statement
Show that function
Y = C sin θ (5cos2θ - 1 )ei\phi
satisfies Scrhödinger equation for hydrogen?
Homework Equations
The Attempt at a Solution
I derivated the required elements of the equation but ended up to some messy equation with lots of sines and...
Hi,
I'm trying to set up a programme to compute the numerical solution to the time dependant schrodinger equation of a ground state wave packet in a harmonic oscillator using the leapfrog method. I've been at it for two weeks trying different methods and I'm starting to get extremely stressed...
Hi,
Note: I will be sloppy with constant factors in this post. Only the general structure of the equations matters.
Consider a particle in a linear potential,
\frac{\mathrm d^2}{\mathrm d x^2} \psi(x) + x \psi(x) - E \psi(x) = 0.
Mathematically, this is a second-order ODE, and there...
I have been trying to find an analytic solution to the time-dependent Schrodinger Equation. I plan to make a movie of the probability function as it changes over time, but I can't seem to find any analytic solution for the wave function.
Is it possible to solve the time-dependent Schrodinger...
Homework Statement
The solution of the Schrodinger equation for atom depends on four quantum numbers: the principal n, the orbital l, magnetic m1, and the spin Ms
n = 1, 2, 3, 4, ... (integers)
l = 0, 1, 2, ... (n-1)
m1 = -1, -1+1,...0...1-1, 1
Ms = -1/2, 1/2
List all possible values of...
I discovered physics at a later age and am trying to learn more about Schrodinger's equation, here it is in one dimension -- got to crawl before you walk, I guess -- http://scienceworld.wolfram.com/physics/SchroedingerEquation.html == my question is the variable that is multiplied by i x h bar...
hi
i need the schrödinger equation for a particle(electron) in a ring under the influence of a magnetic field that goes through perpendicular to the plane of the ring and i want to consider the spin too.
Well, the particle in the ring is pretty easy:
- \frac{ \hbar^2}{2mr^2}...
The postulates of quantum mechanics include:
(1) Schrodinger's equation describes how the wave function of a system changes over time, and appears to make the wave function continuous over time.
(2) When a measurement is made of quantity m, the wave function instantly changes to an...
Homework Statement
A particle of mass m is confined in a two-dimensions by the potential energy V = 1/2k(x2+4y2). Write down the Schrodinger equation for the system. Write down the ground state wave function and find the lowest four energy levels in terms of the quantities ħ, k, m etc. Make...
ψ and its derivatives occur only linearly in the Schrodinger equation, that is, second or higher powers of these quantities do not appear in the equation.
Schrodinger equation for a free particle is
i\hbar∂ψ(x,t)/∂t = (-\hbar2/2m)(∂2ψ(x,t)/∂x2)
Here (∂2ψ(x,t)/∂x2) is second power of ψ. Then...
Homework Statement
Hello! I'm looking at a situation where there is a finite potential Vo for x<0, but zero potential for x>0. For a particle moving from left to right, I'm wondering what coefficients for the solution to the Schrodinger equation are equal to zero, and also how to prove that...
Hamilton-Jacobi Equation related to Schrodinger??
Where it comes from the Schrodinger equation? Is it related to Hamilton-Jacobi equation? And
any good text to consult??
Homework Statement
We have been examining a one-dimensional infinite square well where the infinite walls are located at -b and +b. The energy levels in this quantum system are non-degenerate, that is for each energy there is only one wave function. Let us place an infinite potential step...
hi
i was currently thinking about this step here:
\langle \psi_n, - \Delta \psi_n \rangle = \int |\nabla \psi_n|^2 dx
how do you get from the laplacian to this other expression?