638 research outputs found
Unconventional superfluidity of superconductivity on Penrose lattice
We theoretically investigate the gap function, superfluid density and the
transition temperature of the superconductivity (SC) on semi-periodic Penrose
lattice, where an attractive Hubbard model is adopted as an example. Firstly,
we clarify that the gap function, density of states and superfluid density are
all positively correlate to the extended degree of single particle states
around the Fermi energy. Secondly, we identify that the paramagnetic component
of the superfluid density does not decay to zero in the thermodynamic limit,
which is completely different from the periodic system. The difference between
the diamagnetic and paramagnetic currents keeps stable with whatever scaling,
which is consistent with recent experimental results that although the
superfluid density is lower than that of the periodic system, the system has
bulk SC. Thirdly, we find that both the superfluid density and SC transition
temperature can be boosted with the increase of disorder strength, which should
be general to quasicrystal but unusual to periodic systems, reflecting the
interplay between the underlying geometry and disorder.Comment: 7 pages, 4 figures. version accepted by Sci. China-Phys. Mech. &
Astro
Controlling Frequency-Domain Hong-Ou-Mandel Interference via Electromagnetically Induced Transparency
Hong-Ou-Mandel (HOM) interference is a compelling quantum phenomenon that
demonstrates the nonclassical nature of single photons. Herein, we investigate
an electromagnetically induced transparency-based double-Lambda four-wave
mixing system from the perspective of quantized light fields. The system can be
used to realize efficient HOM interference in the frequency domain. By using
the reduced density operator theory, we demonstrate that, although the
double-Lambda medium does not exhibit phase-dependent properties for the
closed-loop case of two incident single photons, frequency-domain HOM
two-photon interference occurs. For experimentally achievable optical depth
conditions, our theory indicates that this double-Lambda scheme can perform
high-fidelity Hadamard gate operations on frequency-encoded single-photon
qubits, and thereby generate HOM two-photon NOON states with a fidelity greater
than 0.99. Furthermore, we demonstrate that this scheme can be used to realize
arbitrary single-qubit gates and two-qubit SWAP gates by simply controlling the
laser detuning and phase, exhibiting its multifunctional properties and
providing a new route to scalable optical quantum computing.Comment: 10 pages, 5 figure
Poly[(acetato-κ2 O,O′)aquaÂ(μ4-1H-benzimidazole-5,6-dicarboxylÂato-κ5 N 3:O 5,O 5′:O 5,O 6:O 6′)praseodymium(III)]
In the title complex, [Pr(C9H4N2O4)(C2H3O2)(H2O)]n, the PrIII ion is coordinated by five O atoms and one N atom from four benzimidazole-5,6-dicarboxylÂate ligands, two O atoms from an acetate ligand and one water molÂecule, giving a tricapped trigonal-prismatic geometry. The benzimidazole-5,6-dicarboxylÂate and acetate ligands connect the PrIII ions, forming a layer in the ac plane; the layers are further linked by N—H⋯O and O—H⋯O hydrogen bonding and π–π stacking interÂactions between neighboring pyridine rings [the centroid–centroid distance is 3.467 (1) Å], assembling a three-dimensional supraÂmolecular network. The acetate methyl group is disordered over two positions with site-occupancy factors of 0.75 and 0.25
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