Questions tagged [non-linear-schroedinger]
The non-linear-schroedinger tag has no usage guidance.
27
questions
2
votes
1answer
39 views
Derivation of non-linear Schrödinger equation from many-body QM
I hope this (and not MathOverflow) is the right place to post this question. I am a math student taking a methods of mathematical physics course, in which we cover the solution theory the non-linear ...
0
votes
0answers
14 views
Treatment of a light pulse moving from linear material A into non-linear material B
When I simulate the propagation of a pulse through a material without non-linear effects, I can use the non-linear schrödinger equation
$$\partial_tE=\frac{i}{2k_0}\nabla^2E$$
with $k_0$ the wave ...
0
votes
1answer
48 views
Soliton solution of the NLS equation
My understanding of soliton - it is a moving pulse in a medium which does not change its structure with time. It has other properties like no interaction with other solitons (this could certainly be ...
1
vote
0answers
92 views
Lax pairs, Nonlinear Schrodinger Equation
Briefly: I have two Lax pairs in matrix form and using compatibility condition I have found a nonlinear partial differential equation system. I have searched this system very much seems the nonlinear ...
1
vote
0answers
33 views
Intuition behind focusing vs defocusing in integrable systems like NLS, KdV, mKdV
The following are examples of integrable systems arising from the AKNS system (check out AKNS paper here and a short Wikipedia description)
Non-Linear Schrodinger equation
Korteweg-de Vries equation
...
0
votes
1answer
51 views
Conversion of the nonlinear schrodinger equation from $\partial_zE$ to $\partial_tE$
While reading some papers about the nonlinear schrodinger equation (NLS) I noticed that the authors sometimes use (for the linear case)
$$\partial_zE=\frac{i}{2k_0}\nabla^2E$$
and sometimes
$$\...
0
votes
1answer
53 views
Linearizing the Lugiato-Lefever Partial Differential Equation
Problem Statement:
Given the Lugiato-Lefever equation, linearize the equation and determine the dynamics near a stationary solution by looking for a stationary solution with a small perturbation.
...
-1
votes
1answer
154 views
Does the non-linear Schrodinger equation satisfy quantum mechanics rules?
Thinking about the 0+1 dimensional (time-only) non-linear Schrodinger equation:
$$i\frac{\partial}{\partial t} \psi(t) =\kappa |\psi(t)|^2 \psi(t).$$
Treating $\psi$ as a wave function instead of a ...
0
votes
1answer
357 views
correlation function in Fourier space
I'm reading this paper and want to prove eq (8):
The field $\psi(\mathbf{x}) \in \mathbb{C}$ exists in a finite periodic 2D square box (of side length $L$), and has a Fourier series expansion, and ...
1
vote
1answer
77 views
Physical significance of orbital stability
I saw the orbital stability in Wiki, I just understand it from mathematics angle. But in physical, what is its mean? Since I saw many paper talk about the stability of Schrödinger equation, I think ...
2
votes
0answers
57 views
Is the Schrödinger-Newton equation time-reversal symmetric? What about PT-symmetry or similar symmetries?
I tried to figure it out myself. If you take the integro-differential form of the equation, a complex square of the time-dependent wavefunction appears.. It seems to me that this means the equation ...
0
votes
1answer
305 views
Is there anywhere online where I could simulate the schrodinger equation with different Hamiltonian's? [duplicate]
I have a code which simulates the Schrodinger equation and it works good for the harmonic potential, I have checked that. Now, i have changed the Hamiltonian, I have the results but I want to compare ...
4
votes
0answers
161 views
Inverse Scattering Transform (IST) for the Linear Schrödinger Equation
I know that the Inverse Scattering Transform (IST) has been employed to solve, for instance, the KdV equation and I believe also other nonlinear PDEs, such as the NLS.
However, if we consider the ...
1
vote
1answer
555 views
Split step method for nonlinear Schrodinger equation does not result in self focusing
I'm trying to simulate self focusing in the case of anomalous dispersion and positive Kerr nonlinearity in the nonlinear Schrödinger equation $$\frac{\partial a}{\partial t} - i\frac{\partial^2 a}{\...
0
votes
1answer
95 views
Applications of optical rogue waves
It has been recently (2014) discovered that rogue waves arise not only in the context of deep sea waves, but also in that of fiber optics. To be precise, consider a single-mode fiber, which its slowly ...
24
votes
1answer
654 views
Aether existance in alternate universe made of Bose-Einstein condensate
I came across an interesting question which was shown to me by my professor, it is as follows:
Investigation of an alternative Universe:
This Universe contains three spatial and one time ...
2
votes
0answers
247 views
Solving Higher-Order Kinetic Energy Term (Gross-Pitaevskii equation) [closed]
Consider now propagation of non-linear waves in one-dimensional chain of dimers governed by the non-linear Schrödinger equation for the normalized wave envelope $\Psi(x,t)$,
$$
i \frac{\partial \Psi}{...
2
votes
1answer
332 views
Energy density in Gross-Pitaevskii equation
I guess this is a straightforward question but I was wondering if I can get an explicit steps toward the answer.
Using the Gross-Pitaevskii equation:
$$ \tag{1} i \hbar\frac{\partial\psi\left(x,t\...
1
vote
0answers
54 views
Mode distribution and Phase constant for nonlinear optical fiber
While going through the derivation of Nonlinear Schrodingers equation from the Helmholtz equation I came across the following two pdes,
$\nabla_\perp^2 F + \left[ \epsilon\left(\omega\right) k_0^2 -
\...
1
vote
0answers
33 views
Solution to periodic potential GP equation
Consider the boundary condition $\psi(0)=\psi(2\pi)$ and the Hamiltonian (and corresponding nonlinear Schrödinger equation):
$$\left[\left(-i\frac{\partial}{\partial\theta}-\Omega\right)^2+2\pi\gamma|\...
3
votes
1answer
251 views
How to define quantum chaos?
I was told that quantum chaos is just a system whose Hamiltonian's classical version shows chaotic behavior. However, I just wondering
what happens when one eigenstate of this Hamiltonian evolves?
...
1
vote
0answers
87 views
Nonlinear Saturated Schrodinger Equation in 1D- Physical Models
I'm studying the Nonlinear 1d Schrodinger equation
$$i\psi _t + \psi '' + |\psi |^{2p} \psi - \epsilon |\psi | ^{2q} \psi = 0\, , \quad t>0, x\in \mathbb{R}\, ,$$
and specifically, its solitary ...
0
votes
1answer
101 views
Purpose of the multidimensional NLSE/GNLSE
I know the purpose of the NLSE (Evolution of a complex field envelope in a nonlinear dispersive medium). Usually I am solving the 1d-GNLSE when simulating the propagation of a light pulse through a ...
1
vote
0answers
180 views
The Nonlinear Schrodinger Equation (NLSE) [closed]
I am trying to show that the NLSE:
$$\frac{\partial A(z,T)}{\partial z} = -i \frac{\beta_2}{2} \frac{\partial^2A}{\partial T^2} + i \gamma |A|^2 A$$
may be cast in the form:
$$\frac{\partial U(z,\...
1
vote
0answers
90 views
Nonlinear Schrodinger Equation perturbation stability
Consider the nonlinear Schrödinger equation
$i\frac{\partial A}{\partial z} -\frac{\beta_2}{2}\frac{\partial^2 A}{\partial T^2}+\gamma|A|^2A=0$
This has steady state solution $A(z,T)=\sqrt{P_0}\exp\...
10
votes
2answers
331 views
Deducing instability growth rates from the Hamiltonian for the non-linear Schrödinger equation
Consider the following nonlinear Schrödinger equation (NLSE):
$$A_t+iA_{xx}+i|A|^2A = 0, \tag{1}$$
where $A$ is a complex valued function of $(x,t)$.
A solution to this equation is $$A=a_oe^{-ia_o^2t}...
7
votes
2answers
2k views
Difference between real time and imaginary time propagation?
Suppose I want to solve a non-linear Schrödinger equation using imaginary time propagation to get the ground state solution. I choose $t = - i \tau$, and then solve the equation using the split-step ...
