4,725 research outputs found
Quantum contact interactions
The existence of several exotic phenomena, such as duality and spectral
anholonomy is pointed out in one-dimensional quantum wire with a single defect.
The topological structure in the spectral space which is behind these phenomena
is identified.Comment: A lecture presented at the 2nd Winter Institute on Foundations of
Quantum Theory and Quantum Optics (WINST02), Jan. 2-11, 2002, S.N.Bose
Institute, Calcutta, India: 8 pages latex with Indian Acad. Sci. style fil
No Open Cluster in the Ruprecht 93 Region
UBVI CCD photometry has been obtained for the Ruprecht 93 (Ru 93) region. We
were unable to confirm the existence of an intermediate-age open cluster in Ru
93 from the spatial distribution of blue stars. On the other hand, we found two
young star groups in the observed field: the nearer one (Ru 93 group) comprises
the field young stars in the Sgr-Car arm at d ~ 2.1 kpc, while the farther one
(WR 37 group) is the young stars around WR 37 at d ~ 4.8 kpc. We have derived
an abnormal extinction law (Rv = 3.5) in the Ruprecht 93 region.Comment: 6 pages, 6 figures, JKAS 2010, in press (Aug issue
Quantum anholonomies in time-dependent Aharonov-Bohm rings
Anholonomies in eigenstates are studied through time-dependent variations of
a magnetic flux in an Aharonov-Bohm ring. The anholonomies in the eigenenergy
and the expectation values of eigenstates are shown to persist beyond the
adiabatic regime. The choice of the gauge of the magnetic flux is shown to be
crucial to clarify the relationship of these anholonomies to the eigenspace
anholonomy, which is described by a non-Abelian connection in the adiabatic
limit.Comment: 6 pages. Fixed typ
Equivalence of Local and Separable Realizations of the Discontinuity-Inducing Contact Interaction and Its Perturbative Renormalizability
We prove that the separable and local approximations of the
discontinuity-inducing zero-range interaction in one-dimensional quantum
mechanics are equivalent. We further show that the interaction allows the
perturbative treatment through the coupling renormalization.
Keywords: one-dimensional system, generalized contact interaction,
renormalization, perturbative expansion. PACS Nos: 3.65.-w, 11.10.Gh, 31.15.MdComment: ReVTeX 7pgs, doubl column, no figure, See also the website
http://www.mech.kochi-tech.ac.jp/cheon
A general approximation of quantum graph vertex couplings by scaled Schroedinger operators on thin branched manifolds
We demonstrate that any self-adjoint coupling in a quantum graph vertex can
be approximated by a family of magnetic Schroedinger operators on a tubular
network built over the graph. If such a manifold has a boundary, Neumann
conditions are imposed at it. The procedure involves a local change of graph
topology in the vicinity of the vertex; the approximation scheme constructed on
the graph is subsequently `lifted' to the manifold. For the corresponding
operator a norm-resolvent convergence is proved, with the natural
identification map, as the tube diameters tend to zero.Comment: 19 pages, one figure; introduction amended and some references added,
to appear in CM
Evolutionary Stability of Ecological Hierarchy
A self-similar hierarchical solution that is both dynamically and
evolutionarily stable is found to the multi dimensional Lotka-Volterra equation
with a single chain of prey-predator relations. This gives a simple and natural
explanation to the key features of hierarchical ecosystems, such as its
ubiquity, pyramidal population distribution, and higher aggressiveness among
higher trophic levels. pacs{87.23.Kg, 89.75.Da, 05.45.-a}
keywords{Lotka-Volterra equation, Trophic pyramid, Self-similarity}Comment: 4 Pages RevTeX4, 1 Fig, 1 Table, shortened by publishers reques
Altruistic Contents of Quantum Prisoner's Dilemma
We examine the classical contents of quantum games. It is shown that a
quantum strategy can be interpreted as a classical strategies with effective
density-dependent game matrices composed of transposed matrix elements. In
particular, successful quantum strategies in dilemma games are interpreted in
terms of a symmetrized game matrix that corresponds to an altruistic game plan.Comment: Revised according to publisher's request: 4 pgs, 2 fgs, ReVTeX4. For
more info, go to http://www.mech.kochi-tech.ac.jp/cheon
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