| 1. |
- Guica, Monica
(author)
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An integrable Lorentz-breaking deformation of two-dimensional CFTs
- 2018
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In: SciPost Physics. - : Stichting SciPost. - 2542-4653. ; 5:5
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Journal article (peer-reviewed)abstract
- It has been recently shown that the deformation of an arbitrary two-dimensional conformal field theory by the composite irrelevant operator T (T) over bar, built from the components of the stress tensor, is solvable; in particular, the finite-size spectrum of the deformed theory can be obtained from that of the original CFT through a universal formula. We study a similarly universal, Lorentz-breaking deformation of two-dimensional CFTs that possess a conserved U (1) current, J. The deformation takes the schematic form J (T) over bar and is interesting because it preserves an SL (2, R)xU (1) subgroup of the original global conformal symmetries. For the case of a purely (anti) chiral current, we find the finite-size spectrum of the deformed theory and study its thermodynamic properties. We test our predictions in a simple example involving deformed free fermions.
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| 2. |
- Moroz, Sergej, et al.
(author)
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Effective field theory of a vortex lattice in a bosonic superfluid
- 2018
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In: SciPost Physics. - : SCIPOST FOUNDATION. - 2542-4653. ; 5:4
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Journal article (peer-reviewed)abstract
- Using boson-vortex duality, we formulate a low-energy effective theory of a two-dimensional vortex lattice in a bosonic Galilean-invariant compressible superfluid. The excitation spectrum contains a gapped Kohn mode and an elliptically polarized Tkachenko mode that has quadratic dispersion relation at low momenta. External rotation breaks parity and time-reversal symmetries and gives rise to Hall responses. We extract the particle number current and stress tensor linear responses and investigate the relations between them that follow from Galilean symmetry. We argue that elementary particles and vortices do not couple to the spin connection which suggests that the Hall viscosity at zero frequency and momentum vanishes in a vortex lattice. Copyright S. Moroz et al. This work is licensed under the Creative Commons Attribution 4.0 International License. Published by the SciPost Foundation.
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| 3. |
- Patricia, Carvalho, et al.
(author)
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Boron-doping of cubic SiC for intermediate band solar cells: a scanning transmission electron microscopy study
- 2018
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In: SciPost Physics. - Amsterdam, Netherlands : SciPost Foundation. - 2542-4653. ; 5:3, s. 1-17
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Journal article (peer-reviewed)abstract
- Boron (B) has the potential for generating an intermediate band in cubic silicon carbide (3C-SiC), turning this material into a highly efficient absorber for single-junction solar cells. The formation of a delocalized band demands high concentration of the foreign element, but the precipitation behavior of B in the 3C polymorph of SiC is not well known. Here, probe-corrected scanning transmission electron microscopy and secondary-ion mass spectrometry are used to investigate precipitation mechanisms in B-implanted 3C-SiC as a function of temperature. Point-defect clustering was detected after annealing at 1273 K, while stacking faults, B-rich precipitates and dislocation networks developed in the 1573 - 1773 K range. The precipitates adopted the rhombohedral B13C2 structure and trapped B up to 1773 K. Above this temperature, higher solubility reduced precipitation and free B diffused out of the implantation layer. Dopant concentrations E19 at.cm-3 were achieved at 1873 K.
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| 4. |
- Säterskog, Petter
(author)
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A framework for studying a quantum critical metal in the limit N-f -> 0
- 2018
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In: SciPost Physics. - : Stichting SciPost. - 2542-4653. ; 4:3
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Journal article (peer-reviewed)abstract
- We study a model in 1 + 2 dimensions composed of a spherical Fermi surface of N-f flavors of fermions coupled to a massless scalar. We present a framework to non-perturbatively calculate general fermion n-point functions of this theory in the limit N-f -> 0 followed by k(F) -> infinity where k(F) sets both the size and curvature of the Fermi surface. Using this frame-work we calculate the zero-temperature fermion density-density correlation function in real space and find an exponential decay of Friedel oscillations.
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