4,116 research outputs found
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 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
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
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
Eigenvalue and eigenspace anholonomies in hierarchical systems
An adiabatic cycle of parameters in a quantum system can yield the quantum
anholonomies, nontrivial evolution not just in phase of the states, but also in
eigenvalues and eigenstates. Such exotic anholonomies imply that an adiabatic
cycle rearranges eigenstates even without spectral degeneracy. We show that an
arbitrarily large quantum circuit generated by recursive extension can also
exhibit the eigenvalue and eigenspace anholonomies.Comment: 5 pages, 3 figure
Level spacing distribution of pseudointegrable billiard
In this paper, we examine the level spacing distribution of the
rectangular billiard with a single point-like scatterer, which is known as
pseudointegrable. It is shown that the observed is a new type, which is
quite different from the previous conclusion. Even in the strong coupling
limit, the Poisson-like behavior rather than Wigner-like is seen for ,
although the level repulsion still remains in the small region. The
difference from the previous works is analyzed in detail.Comment: 11 pages, REVTeX file, 3 PostScript Figure
Spectral properties on a circle with a singularity
We investigate the spectral and symmetry properties of a quantum particle
moving on a circle with a pointlike singularity (or point interaction). We find
that, within the U(2) family of the quantum mechanically allowed distinct
singularities, a U(1) equivalence (of duality-type) exists, and accordingly the
space of distinct spectra is U(1) x [SU(2)/U(1)], topologically a filled torus.
We explore the relationship of special subfamilies of the U(2) family to
corresponding symmetries, and identify the singularities that admit an N = 2
supersymmetry. Subfamilies that are distinguished in the spectral properties or
the WKB exactness are also pointed out. The spectral and symmetry properties
are also studied in the context of the circle with two singularities, which
provides a useful scheme to discuss the symmetry properties on a general basis.Comment: TeX, 26 pages. v2: one reference added and two update
Extended Standard Map with Spatio-Temporal Asymmetry
We analyze the transport properties of a set of symmetry-breaking extensions
%, both spatial and temporal, of the Chirikov--Taylor Map. The spatial and
temporal asymmetries result in the loss of periodicity in momentum direction in
the phase space dynamics, enabling the asymmetric diffusion which is the origin
of the unidirectional motion. The simplicity of the model makes the calculation
of the global dynamical properties of the system feasible both in phase space
and in controlling-parameter space. We present the results of numerical
experiments which show the intricate dependence of the asymmetric diffusion to
the controlling parameters.Comment: 6 pages latex 2e with 12 epsf fig
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