584 research outputs found
Quantum anomalous Hall phase in synthetic bilayers via twistronics without a twist
We recently proposed quantum simulators of "twistronic-like" physics based on
ultracold atoms and syntheticdimensions [Phys. Rev. Lett. 125, 030504 (2020)].
Conceptually, the scheme is based on the idea that aphysical monolayer optical
lattice of desired geometry is upgraded to a synthetic bilayer system by
identifyingthe internal states of the trapped atoms with synthetic spatial
dimensions. The couplings between the internalstates, i.e. between sites on the
two layers, can be exquisitely controlled by laser induced Raman transitions.By
spatially modulating the interlayer coupling, Moir\'e-like patterns can be
directly imprinted on the latticewithout the need of a physical twist of the
layers. This scheme leads practically to a uniform pattern across thelattice
with the added advantage of widely tunable interlayer coupling strengths. The
latter feature facilitates theengineering of flat bands at larger "magic"
angles, or more directly, for smaller unit cells than in conventionaltwisted
materials. In this paper we extend these ideas and demonstrate that our system
exhibits topologicalband structures under appropriate conditions. To achieve
non-trivial band topology we consider imanaginarynext-to-nearest neighbor
tunnelings that drive the system into a quantum anomalous Hall phase. In
particular,we focus on three groups of bands, whose their Chern numbers triplet
can be associated to a trivial insulator(0,0,0), a standard non-trivial
(-1,0,1) and a non-standard non-trivial (-1,1,0). We identify regimes of
parameterswhere these three situations occur. We show the presence of an
anomalous Hall phase and the appearance oftopological edge states. Our works
open the path for experiments on topological effects in twistronics without
atwistComment: 11 pages, 10 figure
Description of two Enterococcus strains isolated from traditional Peruvian artisanal-produced cheeses with a bacteriocin-like inhibitory activity
The aim of this work was to isolate and to characterize strains of lactic acid bacteria (LAB) with bacteriocin-like inhibitory activity from 27 traditional cheeses artisanal-produced obtained from different Peruvian regions. Twenty Gram+ and catalasenegative strains among 2,277 isolates exhibited bacteriocin-like inhibitory activity against Listeria monocytogenes CWBIB2232 as target strain. No change in inhibitory activity was observed after organic acid neutralization and treatment with catalase of the cell-free supernatant (CFS). The proteinic nature of the antimicrobial activity was confirmed for the twenty LAB strains by proteolytic digestion of the CFS. Two strains, CWBI-B1431 and CWBI-B1430, with the best antimicrobial activity were selected for further researches. These strains were taxonomically identified by phenotypic and genotypic analyses as Enterococcus mundtii (CWBI-B1431) and Enterococcus faecium (CWBI-B1430). The two strains were sensitive to vancomycin (MIC 2 ÎĽg.ml-1) and showed absence of haemolysis
Nanoscale phase separation and pseudogap in the hole-doped cuprates from fluctuating Cu-O-Cu bonds
The pseudogap phenomenology is one of the enigmas of the physics of high-Tc superconductors.
Many members of the cuprate family have now been experimentally characterized with high resolution in both real and momentum space, which revealed highly anisotropic Fermi arcs and local
domains which break rotational symmetry in the CuO2 plane at the intraunit cell level. While
most theoretical approaches to date have focused on the role of electronic correlations and dopinginduced disorder to explain these features, we show that many features of the pseudogap phase
can be reproduced by considering the interplay between electronic and nonlinear electron-phonon
interactions within a model of fluctuating Cu-O-Cu bonds. Remarkably, we find that electronic
segregation arises naturally without the need to explicitly include disorder. Our approach points
not only to the key role played by the oxygen bond in the pseudogap phase, but opens different
directions to explore how nonequilibrium lattice excitations can be used to control the properties of
the pseudogap phase.This work has been supported by the Spanish Ministry
MINECO (National Plan 15 Grant: FISICATEAMO
No. FIS2016-79508-P, SEVERO OCHOA No. SEV2015-0522, FPI), European Social Fund, Fundacio Cellex, Generalitat de Catalunya (AGAUR Grant No. 2017 SGR
1341 and CERCA/Program), EU FEDER, ERC AdG
OSYRIS and NOQIA, ERC StG SEESUPER, EU FETPRO QUIC, and the National Science Centre, PolandSymfonia Grant No. 2016/20/W/ST4/00314. A.D. was
financed by a Juan de la Cierva fellowship (IJCI-2017-
33180). R.W.C. acknowledges funding from the Polish National Center via Miniatura-2 Program Grant No.
2018/02/X/ST3/01718.Peer ReviewedPostprint (author's final draft
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