584 research outputs found
Probing Half-odd Topological Number with Cold Atoms in a Non-Abelian Optical Lattice
We propose an experimental scheme to probe the contribution of a single Dirac
cone to the Hall conductivity as half-odd topological number sequence. In our
scheme, the quantum anomalous Hall effect as in graphene is simulated with cold
atoms trapped in an optical lattice and subjected to a laser-induced
non-Abelian gauge field. By tuning the laser intensity to change the gauge
flux, the energies of the four Dirac points in the first Brillouin zone are
shifted with each other and the contribution of the single Dirac cone to the
total atomic Hall conductivity is manifested. We also show such manifestation
can be experimentally probed with atomic density profile measurements.Comment: 5 pages, 3 figure
Bulk locality from the celestial amplitude
In this paper, we study the implications of bulk locality on the celestial
amplitude. In the context of the four-point amplitude, the fact that the bulk
S-matrix factorizes locally in poles of Mandelstam variables is reflected in
the imaginary part of the celestial amplitude. In particular, on the real axis
in the complex plane of the boost weight, the imaginary part of the celestial
amplitude can be given as a positive expansion on the Poincar\'e partial waves,
which are nothing but the projection of flat-space spinning polynomials onto
the celestial sphere. Furthermore, we derive the celestial dispersion relation,
which relates the imaginary part to the residue of the celestial amplitude for
negative even integer boost weight. The latter is precisely the projection of
low energy EFT coefficients onto the celestial sphere. We demonstrate these
properties explicitly on the open and closed string celestial amplitudes.
Finally, we give an explicit expansion of the Poincar\'e partial waves in terms
of 2D conformal partial waves.Comment: 43 pages, 10 figures. v2: typos corrected, minor clarifications
added, SciPost published versio
Hexaaquacobalt(II) bis{[N-(4-methoxy-2-oxidobenzylidene)glycylglycinato]copper(II)} hexahydrate
In the crystal structure of the title compound, [Co(H2O)6][Cu(C12H11N2O5)]2·6H2O, the CoII atom is located on an inversion center and coordinated by six water molecules in a slightly distorted octahedral geometry. The CuII atom is chelated by the Schiff base ligand in a distorted CuN2O2 square-planar geometry. An extensive O—H⋯O hydrogen-bonding network is present in the crystal structure
IEEE 802.11be Wi-Fi 7: Feature Summary and Performance Evaluation
While the pace of commercial scale application of Wi-Fi 6 accelerates, the
IEEE 802.11 Working Group is about to complete the development of a new
amendment standard IEEE 802.11be -- Extremely High Throughput (EHT), also known
as Wi-Fi 7, which can be used to meet the demand for the throughput of 4K/8K
videos up to tens of Gbps and low-latency video applications such as virtual
reality (VR) and augmented reality (AR). Wi-Fi 7 not only scales Wi-Fi 6 with
doubled bandwidth, but also supports real-time applications, which brings
revolutionary changes to Wi-Fi. In this article, we start by introducing the
main objectives and timeline of Wi-Fi 7 and then list the latest key techniques
which promote the performance improvement of Wi-Fi 7. Finally, we validate the
most critical objectives of Wi-Fi 7 -- the potential up to 30 Gbps throughput
and lower latency. System-level simulation results suggest that by combining
the new techniques, Wi-Fi 7 achieves 30 Gbps throughput and lower latency than
Wi-Fi 6.Comment: 6 pages, 4 figure
Structural, electronic, magnetic properties of Cu-doped lead-apatite PbCu(PO)O
The recent report of superconductivity in the Cu-doped PbPO compound
stimulates the extensive researches on its physical properties. Herein, the
detailed atomic and electronic structures of this compound are investigated,
which are the necessary information to explain the physical properties,
including possible superconductivity. By the first-principles electronic
structure calculations, we find that the partial replacement of Pb at site
by Cu atom, instead of Pb at site, plays a crucial role in dominating the
electronic state at Fermi energy. The electronic orbitals of Cu atom
emerge near the Fermi energy and exhibit strong spin-polarization, resulting in
the local moment around the doped Cu atom. Particularly, the ground state of
PbCu(PO)O (x = 1) is determined to be a semiconducting
phase, in good agreement with the experimental measurements
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