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Wyszukujesz frazę "Quantum graphs" wg kryterium: Wszystkie pola


Wyświetlanie 1-12 z 12
Tytuł:
Edge Switching Transformations of Quantum Graphs
Autorzy:
Aizenman, M.
Schanz, H.
Smilansky, U.
Warzel, S.
Powiązania:
https://bibliotekanauki.pl/articles/1030017.pdf
Data publikacji:
2017-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.45.Mt
02.10.Ox
Opis:
Discussed here are the effects of basics graph transformations on the spectra of associated quantum graphs. In particular it is shown that under an edge switch the spectrum of the transformed Schrödinger operator is interlaced with that of the original one. By implication, under edge swap the spectra before and after the transformation, denoted by {Eₙ}^{∞}ₙ₌₁ and {Ẽₙ}^{∞}ₙ₌₁ correspondingly, are level-2 interlaced, so that Eₙ-₂ ≤ Ẽₙ ≤ Eₙ₊₂. The proofs are guided by considerations of the quantum graphs' discrete analogs.
Źródło:
Acta Physica Polonica A; 2017, 132, 6; 1699-1703
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Geometric properties of quantum graphs and vertex scattering matrices
Autorzy:
Kurasov, P.
Nowaczyk, M.
Powiązania:
https://bibliotekanauki.pl/articles/255512.pdf
Data publikacji:
2010
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
scattering theory
quantum graphs
matching (boundary) conditions
Opis:
Differential operators on metric graphs are investigated. It is proven that vertex matching (boundary) conditions can be successfully parameterized by the vertex scattering matrix. Two new families of matching conditions are investigated: hyperplanar Neumann and hyperplanar Dirichlet conditions. Using trace formula it is shown that the spectrum of the Laplace operator determines certain geometric properties of the underlying graph.
Źródło:
Opuscula Mathematica; 2010, 30, 3; 295-309
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inverse Problems for Quantum Graphs: Recent Developments and Perspectives
Autorzy:
Kurasov, P.
Powiązania:
https://bibliotekanauki.pl/articles/1492443.pdf
Data publikacji:
2011-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
03.65.Nk
73.63.-b
85.35.-p
Opis:
An introduction into the area of inverse problems for the Schrödinger operators on metric graphs is given. The case of metric finite trees is treated in detail with the focus on matching conditions. For graphs with loops we show that for almost all matching conditions the potential on the loop is not determined uniquely by the Titchmarsh-Weyl function. The class of all admissible potentials is characterized.
Źródło:
Acta Physica Polonica A; 2011, 120, 6A; A-132-A-141
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Inverse Problem for Quantum Graphs with One Cycle
Autorzy:
Kurasov, P.
Powiązania:
https://bibliotekanauki.pl/articles/1585121.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
03.65.Nk
73.63.-b
85.35.-p
Opis:
Quantum graphs having one cycle are considered. It is shown that if the cycle contains at least three vertices, then the potential on the graph can be uniquely reconstructed from the corresponding Titchmarsh-Weyl function (Dirichlet-to-Neumann map) associated with graph's boundary, provided certain non-resonant conditions are satisfied.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 765-771
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental Study of Quantum Graphs with Simple Microwave Networks: Non-Universal Features
Autorzy:
Fu, Z.
Koch, T.
Antonsen, T.
Ott, E.
Anlage, S.
Powiązania:
https://bibliotekanauki.pl/articles/1030007.pdf
Data publikacji:
2017-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
Quantum graphs
universal fluctuations
impedance
random coupling model
microwave graphs
Opis:
Quantum graphs provide a setting to test the hypothesis that all ray-chaotic systems show universal wave chaotic properties. Here, an experimental setup consisting of a microwave coaxial cable network is used to simulate quantum graphs. The networks which are large compared to the wavelength, are constructed from coaxial cables connected by T junctions. The distributions of impedance statistics are obtained from experiments on an ensemble of tetrahedral networks. The random coupling model (RCM) is applied in an attempt to uncover the universal statistical properties of the system. Deviations from RCM predictions have been observed in that the statistics of diagonal and off-diagonal impedance elements are different. It is argued that because of the small finite-size quantum graphs utilized here there will be non-universal results.
Źródło:
Acta Physica Polonica A; 2017, 132, 6; 1655-1660
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pseudo-Orbit Expansion for the Resonance Condition on Quantum Graphs and the Resonance Asymptotics
Autorzy:
Lipovský, J.
Powiązania:
https://bibliotekanauki.pl/articles/1189973.pdf
Data publikacji:
2015-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
03.65.Ge
03.65.Nk
02.10.Ox
Opis:
In this note we explain the method how to find the resonance condition on quantum graphs, which is called pseudo-orbit expansion. In three examples with standard coupling we show in detail how to obtain the resonance condition. We focus on non-Weyl graphs, i.e. the graphs which have fewer resonances than expected. For these graphs we explain benefits of the method of "deleting edges" for simplifying the graph.
Źródło:
Acta Physica Polonica A; 2015, 128, 6; 968-973
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Surgery of Graphs: M-Function and Spectral Gap
Autorzy:
Kurasov, P.
Powiązania:
https://bibliotekanauki.pl/articles/1030010.pdf
Data publikacji:
2017-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
quantum graphs
spectral theory
Opis:
We discuss behaviour of the spectral gap for quantum graphs when two metric graphs are glued together. It appears that precise answer to this question can be given using a natural generalisation of the Titchmarsh-Weyl M-functions.
Źródło:
Acta Physica Polonica A; 2017, 132, 6; 1666-1671
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental Determination of the Autocorrelation Function of Level Velocities for Microwave Networks Simulating Quantum Graphs
Autorzy:
Ławniczak, M.
Borkowska, A.
Hul, O.
Bauch, S.
Sirko, L.
Powiązania:
https://bibliotekanauki.pl/articles/1492514.pdf
Data publikacji:
2011-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.45.Mt
03.65.Nk
Opis:
The autocorrelation function c(x) of level velocities is studied experimentally. The measurements were performed for microwave networks simulating quantum graphs. One and two ports measurements of the scattering matrix Ŝ necessary for determining c(x) were realized for the networks possessing 5 and 6 vertices, respectively. The network with six vertices was fully connected. In the case of the networks with five vertices, additionally to the fully connected configuration, we measured the networks without the bond connecting input/output vertices. The obtained experimental results besides the autocorrelation function of level velocities, also the nearest-neighbor spacing distribution and parametric velocities distribution are compared to the predictions of random matrix theory and numerical results.
Źródło:
Acta Physica Polonica A; 2011, 120, 6A; A-185-A-190
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Torsion in Cohomology Groups of Configuration Spaces
Autorzy:
Maciążek, T.
Sawicki, A.
Powiązania:
https://bibliotekanauki.pl/articles/1030016.pdf
Data publikacji:
2017-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
Quantum graphs
quantum statistics
vector bundles
homology groups
Opis:
An important and surprising discovery in physics in the last fifty years is that if quantum particles are constrained to move in two rather than three dimensions, they can in principle exhibit new forms of quantum statistics, called anyons. Although anyons were initially only a theoretical concept, they quickly proved to be useful in explaining one of the most significant discoveries of condensed matter physics in the last century, i.e. fractional quantum Hall effect. Recently, it was shown that particles constrained to move on a graph can exhibit even more exotic forms of quantum statistics, depending on the topology of the graph. In this paper we discuss what possible new quantum signatures of topology may arise when one takes into account more complex topological information, called higher (co)homology groups, which may also be associated with graph configuration spaces. In particular we focus on the significance of a torsion component.
Źródło:
Acta Physica Polonica A; 2017, 132, 6; 1695-1698
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On reflectionless equi-transmitting matrices
Autorzy:
Kurasov, P.
Ogik, R.
Rauf, A.
Powiązania:
https://bibliotekanauki.pl/articles/255075.pdf
Data publikacji:
2014
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
quantum graphs
vertex scattering matrix
equi-transmitting matrices
Opis:
Reflectionless equi-transmitting unitary matrices are studied in connection to matching conditions in quantum graphs. All possible such matrices of size 6 are described explicitly. It is shown that such matrices form 30 six-parameter families intersected along 12 five-parameter families closely connected to conference matrices.
Źródło:
Opuscula Mathematica; 2014, 34, 3; 483-501
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Missing Level Statistics for Microwave Networks Simulating Quantum Chaotic Graphs Without Time Reversal Symmetry - the Case of Randomly Lost Resonances
Autorzy:
Ławniczak, M.
Białous, M.
Yunko, V.
Bauch, S.
Dietz, B.
Sirko, L.
Powiązania:
https://bibliotekanauki.pl/articles/1030011.pdf
Data publikacji:
2017-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.40.-a
05.45.Mt
05.45.Tp
03.65.Sq
Opis:
We present experimental and numerical studies for level statistics in incomplete spectra obtained with microwave networks simulating quantum chaotic graphs with broken time reversal symmetry. We demonstrate that, if resonance frequencies are randomly removed from the spectra, the experimental results for the nearest-neighbor spacing distribution, the spectral rigidity and the average power spectrum are in good agreement with theoretical predictions for incomplete sequences of levels of systems with broken time reversal symmetry.
Źródło:
Acta Physica Polonica A; 2017, 132, 6; 1672-1676
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fractional Revival of Threshold Graphs Under Laplacian Dynamics
Autorzy:
Kirkland, Steve
Zhang, Xiaohong
Powiązania:
https://bibliotekanauki.pl/articles/31552789.pdf
Data publikacji:
2020-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
Laplacian matrix
spectral decomposition
quantum information transfer
fractional revival
Opis:
We consider Laplacian fractional revival between two vertices of a graph $X$. Assume that it occurs at time \(\tau\) between vertices 1 and 2. We prove that for the spectral decomposition \(L=∑_{r=0}^qθ_rE_r\) of the Laplacian matrix $L$ of $X$, for each $r = 0, 1, . . ., q$, either $E_re_1 = E_re_2$, or $E_re_1 = −E_re_2$, depending on whether \(e^{i\tauθ_r}\) equals to 1 or not. That is to say, vertices 1 and 2 are strongly cospectral with respect to $L$. We give a characterization of the parameters of threshold graphs that allow for Laplacian fractional revival between two vertices; those graphs can be used to generate more graphs with Laplacian fractional revival. We also characterize threshold graphs that admit Laplacian fractional revival within a subset of more than two vertices. Throughout we rely on techniques from spectral graph theory.
Źródło:
Discussiones Mathematicae Graph Theory; 2020, 40, 2; 585-600
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-12 z 12

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