52,595 research outputs found
Super Jackstraws and Super Waterwheels
We construct various new BPS states of D-branes preserving 8 supersymmetries.
These include super Jackstraws (a bunch of scattered D- or (p,q)-strings
preserving supersymmetries), and super waterwheels (a number of D2-branes
intersecting at generic angles on parallel lines while preserving
supersymmetries). Super D-Jackstraws are scattered in various dimensions but
are dynamical with all their intersections following a common null direction.
Meanwhile, super (p,q)-Jackstraws form a planar static configuration. We show
that the SO(2) subgroup of SL(2,R), the group of classical S-duality
transformations in IIB theory, can be used to generate this latter
configuration of variously charged (p,q)-strings intersecting at various
angles. The waterwheel configuration of D2-branes preserves 8 supersymmetries
as long as the `critical' Born-Infeld electric fields are along the common
direction.Comment: 23 pages, 10 figure
Schwinger Effect in Non-parallel D1-branes: A Path Integral Approach
We study the Schwinger effect in a system of non-parallel D1-branes for the
bosonic strings using the path integral formalism. We drive the string pair
creation rate by calculating the one loop vacuum amplitude of the setup in
presence of the background electric filed defined along one of the D1-branes.
We find an angle dependent minimum value for the background field and show that
the decaying of vacuum into string pairs takes place for the field above this
value. It is shown that in limit the vacuum
becomes stable and thus no pair creation occurs
Kinetically-controlled thin-film growth of layered - and NaCoO cobaltate
We report growth characteristics of epitaxial -NaCoO and
-NaCoO thin films on (001) sapphire substrates grown by
pulsed-laser deposition. Reduction of deposition rate could change structure of
NaCoO thin film from -phase with island growth mode to
-phase with layer-by-layer growth mode. The
-NaCoO thin film exhibits spiral surface growth with
multiterraced islands and highly crystallized texture compared to that of the
-NaCoO thin film. This heterogeneous epitaxial film growth
can give opportunity of strain effect of physical properties and growth
dynamics of NaCoO as well as subtle nature of structural change.Comment: accepted for publication in Applied Physics Letter
Generation of Atomic Cluster States through the Cavity Input-Output Process
We propose a scheme to implement a two-qubit controlled-phase gate for single
atomic qubits, which works in principle with nearly ideal success probability
and fidelity. Our scheme is based on the cavity input-output process and the
single photon polarization measurement. We show that, even with the practical
imperfections such as atomic spontaneous emission, weak atom-cavity coupling,
violation of the Lamb-Dicke condition, cavity photon loss, and detection
inefficiency, the proposed gate is feasible for generation of a cluster state
in that it meets the scalability criterion and it operates in a conclusive
manner. We demonstrate a simple and efficient process to generate a cluster
state with our high probabilistic entangling gate
Gravitationally Coupled Electroweak Monopole
We present a family of gravitationally coupled electroweak monopole solutions
in Einstein-Weinberg-Salam theory. Our result confirms the existence of
globally regular gravitating electroweak monopole which changes to the
magnetically charged black hole as the Higgs vacuum value approaches to the
Planck scale. Moreover, our solutions could provide a more accurate description
of the monopole stars and magnetically charged black holes
Finite Energy Electroweak Dyon
The recent MoEDAL experiment at LHC to detect the electroweak monopole makes
the theoretical prediction of the monopole mass an urgent issue. We discuss
different ways to estimate the mass of the electroweak monopole. We first
present a scaling argument which indicates that the mass of the electroweak
monopole to be around 4 TeV. To justify this we construct finite energy
analytic dyon solutions which could be viewed as the regularized Cho-Maison
dyon, modifying the coupling strengths of the electromagnetic interaction of
-boson in the standard model. Our result demonstrates that a genuine
electroweak monopole whose mass scale is much smaller than the grand
unification scale can exist, which can actually be detected at the present LHC.Comment: arXiv admin note: substantial text overlap with arXiv:hep-th/0210299,
arXiv:hep-th/970703
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