# What is Schrodinger equation: Definition and 560 Discussions

The Schrödinger equation is a linear partial differential equation that governs the wave function of a quantum-mechanical system. It is a key result in quantum mechanics, and its discovery was a significant landmark in the development of the subject. The equation is named after Erwin Schrödinger, who postulated the equation in 1925, and published it in 1926, forming the basis for the work that resulted in his Nobel Prize in Physics in 1933.Conceptually, the Schrödinger equation is the quantum counterpart of Newton's second law in classical mechanics. Given a set of known initial conditions, Newton's second law makes a mathematical prediction as to what path a given physical system will take over time. The Schrödinger equation gives the evolution over time of a wave function, the quantum-mechanical characterization of an isolated physical system. The equation can be derived from the fact that the time-evolution operator must be unitary, and must therefore be generated by the exponential of a self-adjoint operator, which is the quantum Hamiltonian.
The Schrödinger equation is not the only way to study quantum mechanical systems and make predictions. The other formulations of quantum mechanics include matrix mechanics, introduced by Werner Heisenberg, and the path integral formulation, developed chiefly by Richard Feynman. Paul Dirac incorporated matrix mechanics and the Schrödinger equation into a single formulation. When these approaches are compared, the use of the Schrödinger equation is sometimes called "wave mechanics".

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1. ### A Relation between the density matrix and the annihilation operator

This question is related to equation (1),(3), and (4) in the [paper] : https://arxiv.org/abs/2002.12252
2. ### A Schrodinger equation in quantum field theory

What is the Schrodinger equation in QFT? is it the nonrelativistic approximation of a Klein-Gordon scalar field? or Is there more? I have read that the Schrodinger equation describes a QFT in 0 dimensions. I accept every answer
3. ### A The eigenvalue power method for quantum problems

The classical "power method" for solving one special eigenvalue of an operator works, in a finite-dimensional vector space, as follows: suppose an operator ##\hat{A}## can be written as an ##n\times n## matrix, and its unknown eigenvectors are (in Dirac bra-ket notation) ##\left|\psi_1...
4. ### I Time-dependent to time-independent Schrödinger equation

Why you can do separation of variables in time-dependent Schrödinger equation i \hbar \frac{\partial \psi(\vec{r},t)}{\partial t}=-\frac{\hbar^2}{2m}\Delta \psi(\vec{r},t)+V(\vec{r})\psi(\vec{r},t) with \psi(\vec{r},t)=\varphi(\vec{r})T(t) and when in general is that possible?
5. ### Schrödinger Equation (why are U and -x^2 =0?)

I've already found out how to do it, but, either I got lucky and my procedure is wrong or I just don't get it. Why are U and -x^2 equal 0?
6. ### I Schrodinger Equation from Ritz Variational Method

(This is from W. Greiner Quantum Mechanics, p. 293 from the topic of Ritz Variational Method) 1) Are ##\frac{\delta}{\delta \psi^{*}}## derivatives in equations 11.35a and 11.35b? If this is so, we can differentiate under the integral sign to get ##\int d^3x (\hat{H}\psi)## in equation 11.35a...
7. ### A practice problem with Schrodinger equation

So my question is.. Is schrodinger equation for this problem like this?: How to use the condition that E=0? Thank you
8. ### Edge States in Integer Quantum Hall Effect (IQHE)

Hello there, I am having trouble understanding what parts b-d of the question are asking. By solving the Schrodinger equation I got the following for the Landau Level energies: $$E_{n,k} = \hbar \omega_H(n+\frac 12)+\frac {\hbar^2k^2}{2m}\frac{\omega^2}{\omega_H^2}$$ Where ##\omega_H =...
9. ### Proof of Schrodinger equation solution persisting in time

I've started reading Introduction to Quantum Mechanics by Griffiths and I encountered this proof that once normalized the solution of Schrodinger equation will always be normalized in future: And I am not 100% convinced to this proof. In 1.26 he states that ##\Psi^{*} \frac{\partial...
10. ### A Dieter Zeh's MWI as Schrödinger equation + further assumptions

Sorry for derailing that discussion even further. My reference to Dieter Zeh's German book was unlucky, not just because it is not a peer reviewed paper, but also because I did not remember the exact place with the remark. Since this has bothered me since a long time anyway, I now searched the...
11. ### I Schrodinger equation for N particles in a box

[Pathria, statistical mechanics], pg2 ,when discussing ##N## particles in a volume ##V## "...there will be a large number of different ways in which the total energy E of the system can be distributed among the N particles constituting it. Each of these (different) ways specifies a...
12. ### I Wave function using the time dependent Schrodinger equation

Given a wavefunction ψ(x, 0) of a free particle at initial time t=0, I need to write the general expression of the function at time t. I used a Fourier transform of ψ(x, t) in terms of ψ(p, t), but, i don't understand how to use green's functions and the time dependent schrodinger equation to...
13. ### I Kinetic Energy and Potential Energy of Electrons

Time indepedendent Schrödinger equation for a system (atom or molecule) consisting of N electrons can be written as (with applying Born - Oppenheimer approximation): $$[(\sum_{i=1}^N - \frac {h^2} {2m} \nabla _i ^2) + \sum_{i=1}^N V(r_i) + \sum_{i < j}^N U(r_i,r_j)] \Psi = E \Psi$$ Terms in...
14. ### I Derivation of Schrodinger equation (chicken and egg problem?)

The classical wave equation in 1-D reads: $$\frac{\partial^2 u}{\partial x^2}(x,t) = \frac{1}{v^2}\frac{\partial^2 u}{\partial t^2}(x,t)$$ The D'alembert solution to the wave equation is: $$u(x,t) = f(x+vt) + g(x-vt)$$ so a allowed wave function solution to the 1-Dimensional classical wave...
15. ### How to explain the Quantum Mechanics/Math of the stages of MRI imaging

"B0 is a static magnetic field (produced by a superconducting magnet) that initially causes the protons in the body to align with the field and precess at the larmor frequency along the z axis . From a mathematical perspective this precession around the B0 axis occurs due to the time evolution...
16. ### I Physical interpretation of phase in solutions to Schrodinger's Eqn?

Hello all, So I've been working through the solutions to some simple introductory problems for the Schrodinger Equation like the infinite square well, and I'm trying to make sense of how to think about the phase component. For simplicity's sake, let's start off by assuming we've measured an...
17. ### Exploring the Time-Energy Uncertainty Relation to Solve a Schrodinger Equation

I am guessing time-energy uncertainty relation is the way to solve this. I solved the Schrodinger equation for both the regions and used to continuity at ##x=-a, 0,a## and got ##\psi(-a<x<0) = A\sin(\kappa(x+a))## and ##\psi(0<x<a) = -A\sin(\kappa(x-a))## where ##\kappa^2 = 2mE/\hbar^2##...
18. ### I Proving the Schrodinger Equation

How did scientists prove the accuracy of Schrodinger's equation to describe the behaviour of subatomic particles, especially in the 1920s? How do you monitor an electron's momentum and position when they are so small? Also, if the Schrodinger equation just describes probabilities, is the...
19. ### I Schrodinger Equation as Flow Equation

I was playing with the Schrodinger equation and realized that it can be interpreted as a flow equation. If we set $$\psi = A e^{i \theta}$$ We can put the Schrodinger in the form ∂ψ∂t=(−∇ψ)⋅v+iEψ If v=ℏθm and E=ℏ2m(−∇2AA+∇2θ)+ρV I find this intuitive personally as it shows that the...
20. ### Solving 1-D Schrodinger Equation in Python (Scipy) Numerically

I've tried to make an animation using python to demonstrate the 1-D simple harmonic oscillator and step potential examples. Hope that it can be useful for some of you. Have fun~ :) https://blog.gwlab.page/solving-1-d-schrodinger-equation-in-python-dcb3518ce454 By the way, If you are...
21. ### I General solution of the hydrogen atom Schrödinger equation

Hello everyone! I have two questions which had bothered me for quite some time. I am sorry if they are rather trivial. The first is about the general solution of the hydrogen atom schrödinger-equation: We learned in our quantum mechanics class that the general solution of every quantum system...
22. ### Explain the Schrodinger equation

Please explain in simple words, the meaning of the Schrodinger wave equation in the quantum mechanics model of atom. $$\frac{\partial^{2} \psi}{\partial x^{2}}+\frac{\partial^{2} \psi}{\partial y^{2}}+\frac{\partial^{2} \psi}{\partial z^{2}}+\frac{8 \pi^{2} m}{h^{2}}(E-U) \psi=0$$
23. ### I Why the linear combination of eigenfunctions is not a solution of the TISE

The linear combination of the eigenfunctions gives solution to the Schrodinger equation. For a system with time independent Hamiltonian the Schrodinger Equation reduces to the Time independent Schrodinger equation(TISE), so this linear combination should be a solution of the TISE. It is not...
24. ### Current through Ballistic 2DEG Channel

So I am a bit uncertain what approach is best for solving this problem and how exactly I should approach it, but my strategy right now is: 1. Solve the time-independent Schrödinger Equation with the given Hamiltonian and find energy eigenvalues of system: -Here I struggle a bit with actually...
25. ### I Solving Schrödinger's equation for a hydrogen atom with Euler's method

Hi, first-time poster here I'm a student at HS-level in DK, who has decided to write my annual large scale assignment on Schrödinger's equation. My teacher has only given us a brief introduction to the equation and has tasked us to solve it numerically with Euler's method for the hydrogen atom...
26. ### I Matrix Notation for potential in Schrodinger Equation

I'm working on the time-dependent Schrodinger equation, and come across something I don't understand regarding notation, which is not specific to TDSE but the Schrodinger formalism in general. Let's say we have a non-trivial potential. There is a stage in the development of the TDSE where we...
27. ### AI meets Chemistry in solving electronic Schrödinger equation

Abstract: The electronic Schrödinger equation can only be solved analytically for the hydrogen atom, and the numerically exact full configuration-interaction method is exponentially expensive in the number of electrons. Quantum Monte Carlo methods are a possible way out: they scale well for...
28. ### Schrodinger Equation Research Question

Hey guys, I have had my eye on quantum mechanics for a while now and finally decided that I have a large enough understanding of the concept/math/theories behind it to write a research paper on it, specifically Schrodinger Equation. But I am having a hard time finding a good research question...
29. ### Schrodinger equation in three dimensions. Atom with one electron.

When solving the Schrodinger equation by separation of variables to atom with one electron and in the spherical coordinates, we get $$\Psi = \Theta(\theta)\phi(\varphi)R(r)$$ Specifically, $$\phi = e^{im\rho }$$ The question is, why we adopt this particular solution, in general, we have this...
30. ### Exponential Wavefunction for Infinite Potential Well Problem

Using the boundary conditions where psi is 0, I found that k = n*pi/a, since sin(x) is zero when k*a = 0. I set up my normalization integral as follows: A^2 * integral from 0 to a of (((exp(ikx) - exp(-ikx))*(exp(-ikx) - exp(ikx)) dx) = 1 After simplifying, and accounting for the fact that...

32. ### I Relativistic quantum mechanics

Given that the Minkowski metric implies the Lorentz transformations and special relativity, why do the equations of relativistic quantum mechanics, i.e., the Dirac and Klein-Gordon equations, require a mass term to unite quantum mechanics and special relativity? Shouldn't their formulation in...
33. ### I How do you normalize this wave function?

I have a basic question in elementary quantum mechanics: Consider the Hamiltonian $$H = -\frac{\hbar^2}{2m}\partial^2_x - V_0 \delta(x),$$ where ##\delta(x)## is the Dirac function. The eigen wave functions can have an odd or even parity under inversion. Amongst the even-parity wave functions...
34. ### I Schrodinger equation on the complex disk

Hi to all member of the Physics Forums. I have this question: it is possible consider the analogue of the Schrodinger equation on the plane with configuration space ##(x,p)\in\mathbb{R}^4## on the complex disk ##\mathbb{D}=\{z\in\mathbb{C}: |z|<1\}##? Ssnow

44. ### I Schrodinger equation for a free particle in 3d space

I've got the solution to the question but I just need more detail. I can't work out the first step of the solution to the second step. That should read, I don't know what they multiplied ih-bar by to make it (i/h-bar)^2?
45. ### Help please (concerning eigenfunctions and the Schrödinger equation)

i have an exam in 2 days and in this question i don't know how should i proceed after that i simplified the wave function but i don't know how to confirm that it's an eigenfunction
46. ### I What is the Meaning of the Schrödinger Equation?

I would like to discuss the Schrödinger equation in order to get some insight. The equation, as I understand it, is essentially an expression of the conservation of energy. What it says is that ∆Total Energy= ∆ Kinetic Energy + ∆ Potential Energy. In Schrödinger's day, there were various...
47. ### Non trivial solution to Schrödinger equation for 1-D infinite well

Hello, I am trying to find the solution of Schrödinger equation on matlab. However, when I apply boundary conditions, MATLAB only gives me the solution with both coefficients 0. I want to find the solution : Asin(n*pi*x/L) You can see my code below. Could you please tell me where is my mistake...
48. ### I Solving the Quantum Mechanics of a Hydrogen Atom

Hello, I have a little problem understanding the quantum mechanics of a hydrogen atom. Im troubled with the following question: before i measure the state of a (simplified: without fine-, hyperfinestructure) hydrogen atom, which is the right probability density of finding the electron? is it...
49. ### A Do we need stochasticity in a discrete spacetime?

Suppose that the spacetime is discrete, with only certain positions being possible for any particle. In this case, the probability distributions of particles have nonzero values at the points on which the wavefunction is defined. Do we need randomness in the transitions of particles in such a...
50. ### Show that this Equation Satisfies the Schrodinger Equation

I apologize for the bad formatting: To start off, I'm trying to use the Schrodinger Equation in the form: (ħ/2m) d^2Ψ(x,t)/dx^2+V(x,t)Ψ(x,t)=EΨ(x,t) I couldn't remember if I need to also take the partial derivative with respect to T as well, but I started off with just X. I plugged in my...