1,462 research outputs found
Branes from a non-Abelian (2,0) tensor multiplet with 3-algebra
In this paper, we study the equations of motion for non-Abelian N=(2,0)
tensor multiplets in six dimensions, which were recently proposed by Lambert
and Papageorgakis. Some equations are regarded as constraint equations. We
employ a loop extension of the Lorentzian three-algebra (3-algebra) and examine
the equations of motion around various solutions of the constraint equations.
The resultant equations take forms that allow Lagrangian descriptions. We find
various (5+d)-dimensional Lagrangians and investigate the relation between them
from the viewpoint of M-theory duality.Comment: 44+1 pages, reference added, typos corrected, and several discussions
added; v3, reference added, many typos corrected, the language improved; v4,
some typos and references corrected, final version to appear in J. Phys.
Realization of an Excited, Strongly-Correlated Quantum Gas Phase
Ultracold atomic physics offers myriad possibilities to study strongly
correlated many-body systems in lower dimensions. Typically, only ground state
phases are accessible. Using a tunable quantum gas of bosonic cesium atoms, we
realize and control in one dimensional geometry a highly excited quantum phase
that is stabilized in the presence of attractive interactions by maintaining
and strengthening quantum correlations across a confinement-induced resonance.
We diagnose the crossover from repulsive to attractive interactions in terms of
the stiffness and the energy of the system. Our results open up the
experimental study of metastable excited many-body phases with strong
correlations and their dynamical properties
Creating artificial magnetic fields for cold atoms by photon-assisted tunneling
This paper proposes a simple setup for introducing an artificial magnetic
field for neutral atoms in 2D optical lattices. This setup is based on the
phenomenon of photon-assisted tunneling and involves a low-frequency periodic
driving of the optical lattice. This low-frequency driving does not affect the
electronic structure of the atom and can be easily realized by the same means
which employed to create the lattice. We also address the problem of detecting
this effective magnetic field. In particular, we study the center of mass
wave-packet dynamics, which is shown to exhibit certain features of cyclotron
dynamics of a classical charged particle.Comment: EPL-style, 8 pages, 4 figure
(1,0) superconformal theories in six dimensions and Killing spinor equations
We solve the Killing spinor equations of 6-dimensional (1,0) superconformal
theories in all cases. In particular, we derive the conditions on the fields
imposed by the Killing spinor equations and demonstrate that these depend on
the isotropy group of the Killing spinors. We focus on the models proposed by
Samtleben et al in \cite{ssw} and find that there are solutions preserving 1,2,
4 and 8 supersymmetries. We also explore the solutions which preserve 4
supersymmetries and find that many models admit string and 3-brane solitons as
expected from the M-brane intersection rules. The string solitons are smooth
regulated by the moduli of instanton configurations.Comment: 26 page
Measurement of finite-frequency current statistics in a single-electron transistor
Electron transport in nano-scale structures is strongly influenced by the
Coulomb interaction which gives rise to correlations in the stream of charges
and leaves clear fingerprints in the fluctuations of the electrical current. A
complete understanding of the underlying physical processes requires
measurements of the electrical fluctuations on all time and frequency scales,
but experiments have so far been restricted to fixed frequency ranges as
broadband detection of current fluctuations is an inherently difficult
experimental procedure. Here we demonstrate that the electrical fluctuations in
a single electron transistor (SET) can be accurately measured on all relevant
frequencies using a nearby quantum point contact for on-chip real-time
detection of the current pulses in the SET. We have directly measured the
frequency-dependent current statistics and hereby fully characterized the
fundamental tunneling processes in the SET. Our experiment paves the way for
future investigations of interaction and coherence induced correlation effects
in quantum transport.Comment: 7 pages, 3 figures, published in Nature Communications (open access
On the structure of k-Lie algebras
We show that the structure constants of -Lie algebras, , with a
positive definite metric are the sum of the volume forms of orthogonal
-planes. This generalizes the result for in arXiv:0804.2662 and
arXiv:0804.3078, and confirms a conjecture in math/0211170.Comment: 4 pages, minor changes and a reference adde
Gravity in the 3+1-Split Formalism II: Self-Duality and the Emergence of the Gravitational Chern-Simons in the Boundary
We study self-duality in the context of the 3+1-split formalism of gravity
with non-zero cosmological constant. Lorentzian self-dual configurations are
conformally flat spacetimes and have boundary data determined by classical
solutions of the three-dimensional gravitational Chern-Simons. For Euclidean
self-dual configurations, the relationship between their boundary initial
positions and initial velocity is also determined by the three-dimensional
gravitational Chern-Simons. Our results imply that bulk self-dual
configurations are holographically described by the gravitational Chern-Simons
theory which can either viewed as a boundary generating functional or as a
boundary effective action.Comment: 25 pages; v2: minor improvements, references adde
Quantitative evaluation of polymer gel dosimeters by broadband ultrasound attenuation
Ultrasound has been examined previously as an alternative readout method for irradiated polymer gel dosimeters, with authors reporting varying dose response to ultrasound transmission measurements. In this current work we extend previous work to measure the broadband ultrasound attenuation (BUA) response of irradiated PAGAT gel dosimeters, using a novel ultrasound computed tomography system
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