7,563 research outputs found
Spiky strings on AdS3 x S3 with NS-NS flux
We study rigidly rotating strings in the background of AdS3 x S3 with
Neveu-Schwarz (NS) fluxes. We find two interesting limiting cases corresponding
to the known giant magnon and the new single spike solution of strings in the
above background and write down the dispersion relations among various
conserved charges. We use proper regularization to find the correct relations
among them. We further study the circular and infinite spiky strings on AdS and
study their properties.Comment: 19 pages, added clarification, typos fixe
Magnetic Order Beyond RKKY in the Classical Kondo Lattice
We study the Kondo lattice model of band electrons coupled to classical
spins, in three dimensions, using a combination of variational calculation and
Monte Carlo. We use the weak coupling `RKKY' window and the strong coupling
regime as benchmarks, but focus on the physically relevant intermediate
coupling regime. Even for modest electron-spin coupling the phase boundaries
move away from the RKKY results, the non interacting Fermi surface no longer
dictates magnetic order, and weak coupling `spiral' phases give way to
collinear order. We use these results to revisit the classic problem of 4f
magnetism and demonstrate how both electronic structure and coupling effects
beyond RKKY control the magnetism in these materials.Comment: 6 pages, 4 figs. Improved figures, expanded captions. To appear in
Europhys. Let
Sampling rare fluctuations of height in the Oslo ricepile model
We have studied large deviations of the height of the pile from its mean
value in the Oslo ricepile model. We sampled these very rare events with
probabilities of order by Monte Carlo simulations using importance
sampling. These simulations check our qualitative arguement [Phys. Rev. E, {\bf
73}, 021303, 2006] that in steady state of the Oslo ricepile model, the
probability of large negative height fluctuations about
the mean varies as as with
held fixed, and .Comment: 7 pages, 8 figure
In-Situ absolute phase detection of a microwave field via incoherent fluorescence
Measuring the amplitude and the absolute phase of a monochromatic microwave
field at a specific point of space and time has many potential applications,
including precise qubit rotations and wavelength quantum teleportation. Here we
show how such a measurement can indeed be made using resonant atomic probes,
via detection of incoherent fluorescence induced by a laser beam. This
measurement is possible due to self-interference effects between the positive
and negative frequency components of the field. In effect, the small cluster of
atoms here act as a highly localized pick-up coil, and the fluorescence channel
acts as a transmission line.Comment: 13 pages, 5 figure
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