17,939 research outputs found
Universal Boundary Entropies in Conformal Field Theory: A Quantum Monte Carlo Study
Recently, entropy corrections on nonorientable manifolds such as the Klein
bottle are proposed as a universal characterization of critical systems with an
emergent conformal field theory (CFT). We show that entropy correction on the
Klein bottle can be interpreted as a boundary effect via transforming the Klein
bottle into an orientable manifold with nonlocal boundary interactions. The
interpretation reveals the conceptual connection of the Klein bottle entropy
with the celebrated Affleck-Ludwig entropy in boundary CFT. We propose a
generic scheme to extract these universal boundary entropies from quantum Monte
Carlo calculation of partition function ratios in lattice models. Our numerical
results on the Affleck-Ludwig entropy and Klein bottle entropy for the
-state quantum Potts chains with show excellent agreement with the
CFT predictions. For the quantum Potts chain with , the Klein bottle
entropy slightly deviates from the CFT prediction, which is possibly due to
marginally irrelevant terms in the low-energy effective theory.Comment: 10 pages, 4 figures. Published versio
Evidence for Two-Component Jet in Sw J1644+57
The continued observations of Sw J1644+57 in X-ray and radio bands
accumulated a rich data set to study the relativistic jet launched in this
tidal disruption event. We find that the re-brightening feature in the radio
light curve can be naturally explained by the two-component jet model. The
possible origin of this structured jet are the Blandford-Znajek and
Blandford-Payne mechanisms. We also show that this two-component jet model can
interpret the two kinds of quasi-periodic variations in the X-ray light curve:
a 200 second quasi-periodic oscillation (QPO) and a 2.7-day quasi-periodic
variation. The latter is interpreted by a precessing outer jet launched near
the Bardeen-Petterson radius of a warped disk. The 200s QPO could be
associated with a second, narrower jet sweeping the observer line-of-sight
periodically, which is launched from a spinning black hole in the misaligned
direction with respect to the black hole's angular momentum.Comment: 6 pages, 3 figures. In proceedings of "Swift: 10 Years of Discovery"
congress (Rome, 2-4 December 2014), PoS(SWIFT 10)17
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