All Questions
Tagged with sp.spectral-theory ds.dynamical-systems
18 questions
2
votes
0
answers
41
views
Why has the random Koopman matrix $ G_{xx}^{(-)} G_{yx} $ only eigenvalues on the complex unit circle?
Let U be a $\Bbb{R}^{(n+1)(n+1)} $ matrix with entries drawn from a independent normal distribution,
e.g.
$$ U_{i j} \sim N(0,1) \quad \quad i,j=1,...n+1$$
Let $ G=U U^* $ be a Gram matrix where $ U^* ...
- 253
0
votes
0
answers
39
views
Spectral properties of Ruelle transfer operator
Consider a compact metric space $(X,d)$, a continuous surjective map $T:X \to X$ of finite degree and the space of continuous functions $C(X)$ equipped with the supremum norm. Also, consider only (for ...
- 143
1
vote
0
answers
67
views
Equidistribution on subvarieties of $\mathrm{SL}_n(\mathbb{Z})$
$\DeclareMathOperator\SL{SL}$Let $\Gamma_{\infty}$ be a maximal parabolic subgroup of $\SL_n(\mathbb{Z})$. I believe there are various equidistribution theorems, which say that Iwasawa $x$ coordinates ...
- 2,907
3
votes
0
answers
135
views
the second largest eigenvalue of transfer operators
A Gauss map $T$ is mixing and satisfies Lasota-York inequalities. By Henon's theorem, we know that the transfer operator $\hat{T}$ associated with $T$ has a spectral gap. This means there exists a ...
user509763
4
votes
1
answer
785
views
The definition of simple eigenvalue
This question was posted a long time ago on the mathexchange, but I didn't get any answers there, and despite having discussed it with some colleagues, I don't think I have a definitive answer.
I am ...
- 136
3
votes
1
answer
146
views
spectrum of multiplicative morphisms
Let $T:[0,1]\to[0,1]$ be a continuous map, which is neither surjective nor injective. Put
$$
C([0,1])\ni f\mapsto \Phi(f):=f\circ T\in C([0,1]).
$$
Notice that, under the above conditions, $0\in\sigma(...
- 41
6
votes
0
answers
281
views
Spectral properties of Non-local Differential operators on real line
I am encountering non-local (and nonlinear) PDEs in my work. To compute stability, I am trying to numerically estimate the spectrum of linearized-but-nonlocal version of the said PDEs.
Definition: A ...
- 318
5
votes
0
answers
279
views
The Spectrum of certain differential operators
We fix a Hilbert space isomorphism $\phi:H^{1}\to H^{2}$. Here by $H^{s},\;s=1,2,\;$ we mean the sobolev space on $\mathbb{R}^{2}$ or $S^{2}$.
We consider the following polynomial vector field on ...
- 356
1
vote
0
answers
123
views
null controllability of linear wave equation
Consider the linear wave equation :
$$z_{tt}=\Delta z + k(x) z + h(t) , \; in \; \Omega\times (0,T)$$
Are there sufficient conditions on the functions $k(x)$ and $h(t)$ for which $(z,z_t)$ vanish ...
- 51
1
vote
0
answers
74
views
strong stability for the wave equation
Consider the $n-$dimensional wave equation
$$z_{tt}=\Delta z + k(x) z - \epsilon {1}_\omega z_t, \; in \; \Omega\times (0,T)$$
where $\omega\subset \Omega.$ Can I have $z(t) \to 0,$ as $t\to+\infty$ ...
- 51
1
vote
2
answers
747
views
Exponential stability in nonlinear differential equations
I have this nonlinear differential equation $d\textbf{x}/dt=f(\textbf{x})$, where $\textbf{x}\in \mathbb{R}^n$. There are results which guarantee the convergence of the dynamical system to $\textbf{x}=...
- 519
3
votes
1
answer
289
views
Avalanche Principle for higher dimensional unimodular matrices ?
Hello everyone,
I have a quick question for people working on quasi-periodic Schrodinger operators, Lyapunov exponents for Schrodinger cocycles or in other fields that might make them aware of this ...
- 33
0
votes
1
answer
739
views
Simple system of ODEs with periodic coefficients
I am stuck with a little problem that I cannot solve mith the standard methods I learn at university. I have a system of coupled ODEs:
$f'(t) = P \cos(k t + \Phi_1) g(t)$
$g'(t) = Q \cos(k t + \...
4
votes
3
answers
968
views
Homogeneous linear differential equation system with simple periodical coefficient matrix
Hello, I encountered the following system of linear first-order differential equations:
$y'(z)=A(z) y(z)$
where
$y(z): R \rightarrow R^2$ and
$A(z)=\begin{pmatrix}
0 & B Cos(\alpha z + \Phi_b) ...
- 43
2
votes
1
answer
233
views
sum of Perron-Frobenius operators
My operator is the transfer operator $P$ on $L^1$ functions defined on compact $X$. It is the pre-dual of the operator $U:L^∞ \rightarrow L^∞$ defined by $U(ϕ)=ϕ\circ f$, for a fixed map f on X. I ...
- 39
23
votes
3
answers
3k
views
Trapped rays bouncing between two convex bodies
At some point during my research I was confronted with this problem, but I did not dedicate serious time to it. Anyway it stayed in the back of my mind and I'm still interested in hints for it. ...
- 9,007
5
votes
1
answer
600
views
Spectrum of a generic integral matrix.
My collaborators and I are studying certain rigidity properties of hyperbolic toral automorphisms.
These are given by integral matrices A with determinant 1 and without eigenvalues on the unit circle....
- 4,188
5
votes
1
answer
389
views
Is there a name for this differential operator and/or its corresponding spectrum?
Let $\mathcal{M}$ be a real, compact, orientable manifold and let $X$ be a vector field on $\mathcal{M}$. Consider the functional
$$E(f) = \int_{\mathcal{M}} X_p(f)^2 dV$$
where $X_p(f)$ is the ...
- 3,059