4,545 research outputs found
All-optical transport and compression of ytterbium atoms into the surface of a solid immersion lens
We present an all-optical method to load 174Yb atoms into a single layer of
an optical trap near the surface of a solid immersion lens which improves the
numerical aperture of a microscope system. Atoms are transported to a region 20
um below the surface using a system comprised by three optical dipole traps.
The "optical accordion" technique is used to create a condensate and compress
the atoms to a width of 120 nm and a distance of 1.8 um away from the surface.
Moreover, we are able to verify that after compression the condensate behaves
as a two-dimensional quantum gas.Comment: 5 pages, 5 figure
Blockbusters, Bombs and Sleepers: The income distribution of movies
The distribution of gross earnings of movies released each year show a
distribution having a power-law tail with Pareto exponent .
While this offers interesting parallels with income distributions of
individuals, it is also clear that it cannot be explained by simple asset
exchange models, as movies do not interact with each other directly. In fact,
movies (because of the large quantity of data available on their earnings)
provide the best entry-point for studying the dynamics of how ``a hit is born''
and the resulting distribution of popularity (of products or ideas). In this
paper, we show evidence of Pareto law for movie income, as well as, an analysis
of the time-evolution of income.Comment: 5 pages, 3 figures, to appear in Proceedings of International
Workshop on Econophysics of Wealth Distributions (Econophys-Kolkata I), March
15-19, 200
Anomalous Dimensions from a Spinning D5-Brane
We consider the anomalous dimension of a certain twist two operator in N=4
super Yang-Mills theory. At strong coupling and large-N it is captured by the
classical dynamics of a spinning D5-brane. The present calculation generalizes
the result of Gubser, Klebanov and Polyakov (hep-th/0204051): in order to
calculate the anomalous dimension of a bound state of k coincident strings, the
spinning closed string is replaced by a spinning D5 brane that wraps an S4
inside the S5 part of the AdS5 times S5 metric.Comment: 8 pages, LaTex. v2: figure added. minor changes. To appear in JHE
Patterns in Open String Field Theory Solutions
In open string field theory the kinetic operator mixes matter and ghost
sectors, and thus the ghost structure of classical solutions is not universal.
Nevertheless, we have found from numerical analysis that certain ratios of
expectation values for states involving pure ghost excitations appear to be
universal. We give an analytic expression for these ratios and find good
evidence that they are common to all known solutions of open string field
theory, including the tachyon vacuum solution, lump solutions and string fields
representing marginal deformations. We also draw attention to a close
correspondence between the expectation values for the pure matter components in
the tachyon vacuum solution and those in the solution of a simpler equation for
a ghost number zero string field. Finally we observe that the action of L_0 on
the tachyon condensate gives a state that is approximately factorized into a
matter and a ghost part.Comment: 21 pages, LaTe
Electrons doped in cubic perovskite SrMnO3: isotropic metal versus chainlike ordering of Jahn-Teller polarons
Single crystals of electron-doped SrMnO3 with a cubic perovskite structure
have been systematically investigated as the most canonical
(orbital-degenerate) double-exchange system, whose ground states have been
still theoretically controversial. With only 1-2% electron doping by Ce
substitution for Sr, a G-type antiferromagnetic metal with a tiny spin canting
in a cubic lattice shows up as the ground state, where the Jahn-Teller polarons
with heavy mass are likely to form. Further electron doping above 4%, however,
replaces this isotropic metal with an insulator with tetragonal lattice
distortion, accompanied by a quasi-one-dimensional 3z^2-r^2 orbital ordering
with the C-type antiferromagnetism. The self-organization of such dilute
polarons may reflect the critical role of the cooperative Jahn-Teller effect
that is most effective in the originally cubic system.Comment: 5 pages, 4 figure
Associativity Anomaly in String Field Theory
We give a detailed study of the associativity anomaly in open string field
theory from the viewpoint of the split string and Moyal formalisms. The origin
of the anomaly is reduced to the properties of the special infinite size
matrices which relate the conventional open string to the split string
variables, and is intimately related to midpoint issues. We discuss two steps
to cope with the anomaly. We identify the field subspace that causes the
anomaly which is related to the existence of closed string configurations, and
indicate a decomposition of open/closed string sectors. We then propose a
consistent cut off method with a finite number of string modes that guarantees
associativity at every step of any computation.Comment: 24 pages, LaTe
On Continuous Moyal Product Structure in String Field Theory
We consider a diagonalization of Witten's star product for a ghost system of
arbitrary background charge and Grassmann parity. To this end we use a
bosonized formulation of such systems and a spectral analysis of Neumann
matrices. We further identify a continuous Moyal product structure for a
combined ghosts+matter system. The normalization of multiplication kernel is
discussed.Comment: 18+7 pages, 1 figure, typos correction
Ratio of Tensions from Vacuum String Field Theory
We show analytically that the ratio of the norm of sliver states agrees with
the ratio of D-brane tensions. We find that the correct ratio appears as a
twist anomaly.Comment: 13 pages, lanlmac; version to appear in JHE
On the Universal Tachyon and Geometrical Tachyon
We study properties of non-BPS D(p+1)-brane in the background of k
NS5-branes, with one transverse direction compactified on a circle, from the
point of view of Dirac-Born-Infeld action. We present the analysis of two
different embedding of non-BPS D(p+1)-brane in given background and study the
classical solutions of given world-volume theory. We argue for the
configuration of a non-BPS D(p+1)-brane which allows us to find solutions of
the equations of motion that give unified descriptions of G and U-type branes.Comment: 24 pages, minor change
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