2,450 research outputs found
Physical Mechanism of the d->d+is Transition
We discuss the basic physical mechanism of the d->d+is transition, which is
the currently accepted explanation for the results of tunneling experiments
into planes. Using the first-order perturbation theory, we show that the
zero-bias states drive the transition. We present various order-of-magnitude
estimates and consistency checks that support this picture.Comment: 7 pages, 2 figure
Bootstrapping 3D Fermions with Global Symmetries
We study the conformal bootstrap for 4-point functions of fermions in parity-preserving 3d CFTs, where
transforms as a vector under an global symmetry. We compute
bounds on scaling dimensions and central charges, finding features in our
bounds that appear to coincide with the symmetric Gross-Neveu-Yukawa
fixed points. Our computations are in perfect agreement with the
expansion at large and allow us to make nontrivial predictions at small
. For values of for which the Gross-Neveu-Yukawa universality classes
are relevant to condensed-matter systems, we compare our results to previous
analytic and numerical results.Comment: 29 pages, 7 figure
Bootstrapping 3D Fermions
We study the conformal bootstrap for a 4-point function of fermions
in 3D. We first introduce an embedding
formalism for 3D spinors and compute the conformal blocks appearing in fermion
4-point functions. Using these results, we find general bounds on the
dimensions of operators appearing in the OPE, and also on
the central charge . We observe features in our bounds that coincide with
scaling dimensions in the Gross-Neveu models at large . We also speculate
that other features could coincide with a fermionic CFT containing no relevant
scalar operators.Comment: 45 pages, 8 figures; V2: added references and small clarifications to
match JHEP versio
Fermion-Scalar Conformal Blocks
We compute the conformal blocks associated with scalar-scalar-fermion-fermion
4-point functions in 3D CFTs. Together with the known scalar conformal blocks,
our result completes the task of determining the so-called `seed blocks' in
three dimensions. Conformal blocks associated with 4-point functions of
operators with arbitrary spins can now be determined from these seed blocks by
using known differential operators.Comment: 25 pages; V2: added small clarifications to match JHEP versio
Construction and measurements of a vacuum-swing-adsorption radon-mitigation system
Long-lived alpha and beta emitters in the Rn decay chain on (and
near) detector surfaces may be the limiting background in many experiments
attempting to detect dark matter or neutrinoless double-beta decay, and in
screening detectors. In order to reduce backgrounds from radon-daughter
plate-out onto the wires of the BetaCage during its assembly, an
ultra-low-radon cleanroom is being commissioned at Syracuse University using a
vacuum-swing-adsorption radon-mitigation system. The radon filter shows
~20 reduction at its output, from 7.470.56 to 0.370.12
Bq/m, and the cleanroom radon activity meets project requirements, with a
lowest achieved value consistent with that of the filter, and levels
consistently < 2 Bq/m.Comment: 5 pages, 3 figures, Proceedings of Low Radioactivity Techniques (LRT)
2013, Gran Sasso, Italy, April 10-12, 201
Status of BetaCage: an Ultra-sensitive Screener for Surface Contamination
BetaCage, a gaseous neon time-projection chamber, has been proposed as a viable screener for emitters of low-energy alphas and electrons to which commercial radioactivity counting techniques are insensitive. Using radiopure materials for construction, active and passive shielding from extrinsic backgrounds, large counting area and minimal detector mass, BetaCage will be able to achieve sensitivities of 10^(−5) counts keV^(−1) kg^(−1) day^(−1) in a few days of running time. We report on progress in prototype development work since the last meeting of this workshop
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