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′)aqua­(μ4-1H-benzimidazole-5,6-dicarboxyl­ato-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-dicarboxyl­ate ligands, two O atoms from an acetate ligand and one water mol­ecule, giving a tricapped trigonal-prismatic geometry. The benzimidazole-5,6-dicarboxyl­ate 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 inter­actions between neighboring pyridine rings [the centroid–centroid distance is 3.467 (1) Å], assembling a three-dimensional supra­molecular network. The acetate methyl group is disordered over two positions with site-occupancy factors of 0.75 and 0.25