Entanglement creation and distribution on a graph of exchange-coupled qutrits

We propose a protocol that allows both the creation and distribution of entanglement, resulting in two distant parties (Alice and Bob) conclusively sharing a bipartite Bell State. The system considered is a graph of three-level objects ("qutrits") coupled by SU(3) exchange operators. The protocol begins with a third party (Charlie) encoding two lattice sites in unentangled states, and allowing unitary evolution under time. Alice and Bob perform a projective measurement on their respective qutrits at a given time, and obtain a maximally-entangled Bell state with a certain probablility. We also consider two further protocols, one based on simple repetition and the other based on successive measurements and conditional resetting, and show that the cumulative probability of creating a Bell state between Alice and Bob tends to unity.Comment: Added seven references, clarified argument for eqn (16

Effect of inhomogeneities on the expansion rate of the Universe

While the expansion rate of a homogeneous isotropic Universe is simply proportional to the square-root of the energy density, the expansion rate of an inhomogeneous Universe also depends on the nature of the density inhomogeneities. In this paper we calculate to second order in perturbation variables the expansion rate of an inhomogeneous Universe and demonstrate corrections to the evolution of the expansion rate. While we find that the mean correction is small, the variance of the correction on the scale of the Hubble radius is sensitive to the physical significance of the unknown spectrum of density perturbations beyond the Hubble radius.Comment: 19 pages, 2 figures Version 2 includes some changes in numerical factors and corrected typos. It is the version accepted for publication in Physical review

Quantifying the Reversible Association of Thermosensitive Nanoparticles

Under many conditions, biomolecules and nanoparticles associate by means of attractive bonds, due to hydrophobic attraction. Extracting the microscopic association or dissociation rates from experimental data is complicated by the dissociation events and by the sensitivity of the binding force to temperature (T). Here we introduce a theoretical model that combined with light-scattering experiments allows us to quantify these rates and the reversible binding energy as a function of T. We apply this method to the reversible aggregation of thermoresponsive polystyrene/poly(N-isopropylacrylamide) core-shell nanoparticles, as a model system for biomolecules. We find that the binding energy changes sharply with T, and relate this remarkable switchable behavior to the hydrophobic-hydrophilic transition of the thermosensitive nanoparticles

Artificial quantum confinement in LAO3/STO heterostructure

Heterostructures of transition metal oxides (TMO) perovskites represent an ideal platform to explore exotic phenomena involving the complex interplay between the spin, charge, orbital and lattice degrees of freedom available in these compounds. At the interface between such materials, this interplay can lead to phenomena that are present in none of the original constituents such as the formation of the interfacial 2D electron system (2DES) discovered at the LAO3/STO3 (LAO/STO) interface. In samples prepared by growing a LAO layer onto a STO substrate, the 2DES is confined in a band bending potential well, whose width is set by the interface charge density and the STO dielectric properties, and determines the electronic band structure. Growing LAO (2 nm) /STO (x nm)/LAO (2 nm) heterostructures on STO substrates allows us to control the extension of the confining potential of the top 2DES via the thickness of the STO layer. In such samples, we explore the dependence of the electronic structure on the width of the confining potential using soft X-ray ARPES combined with ab-initio calculations. The results indicate that varying the thickness of the STO film modifies the quantization of the 3d t2g bands and, interestingly, redistributes the charge between the dxy and dxz/dyz bands

Topology and the Kardar-Parisi-Zhang universality class

We study the role of the topology of the background space on the one-dimensional Kardar-Parisi-Zhang (KPZ) universality class. To do so, we study the growth of balls on disordered 2D manifolds with random Riemannian metrics, generated by introducing random perturbations to a base manifold. As base manifolds we consider cones of different aperture angles theta, including the limiting cases of a cylinder (theta = 0, which corresponds to an interface with periodic boundary conditions) and a plane (theta = pi/2, which corresponds to an interface with circular geometry). We obtain that in the former case the radial fluctuations of the ball boundaries approach the Tracy-Widom (TW) distribution of the largest eigenvalue of random matrices in the Gaussian orthogonal ensemble (TW-GOE), while on cones with any aperture angle theta not equal 0 fluctuations correspond to the TW- GUE distribution related with the Gaussian unitary ensemble. We provide a topological argument to justify the relevance of TW-GUE statistics for cones, and state a conjecture which relates the KPZ universality subclass with the background topology.The work of S.N.S., J.R.-L., and R.C. was funded by MINECO (Spain) Grants Nos. FIS2012-33642, FIS2012-38866-C05-01, and FIS2015-66020-C2-1-P. A.C. acknowledges financial support from the EU grants EQuaM (FP7/2007-2013 Grant No. 323714), OSYRIS (ERC-2013-AdG Grant No. 339106), SIQS (FP7-ICT-2011-9 No. 600645), QUIC (H2020-FETPROACT-2014 No. 641122), Spanish MINECO grants (Severo Ochoa SEV-2015-0522 and FOQUS FIS2013-46768-P), Generalitat de Catalunya (2014 SGR 874), and Fundació Cellex

INTRAVITREAL DEXAMETHASONE IMPLANT FOR REFRACTORY MACULAR EDEMA SECONDARY TO VITRECTOMY FOR MACULAR PUCKER.

Purpose: To study the efficacy of a single 0.7 mg dexamethasone intravitreal implant in vitrectomized eyes with refractory macular edema secondary to combined cataract extraction and macular pucker removal. Methods: In 8 eyes of 8 consecutive patients with refractory macular edema secondary to combined cataract extraction and 25-gauge vitrectomy with internal limiting membrane peeling for macular pucker removal, the injection of the 0.7 mg dexamethasone implant was performed. Best-corrected visual acuity, central retinal thickness measured by spectral domain optical coherence tomography, and intraocular pressure were evaluated at baseline, 1 month, and 6 months. Results: After a mean follow-up of 6.75 +/- 0.71 months, best-corrected visual acuity was significantly increased (P < 0.0001) from 20/50 to 20/23 (P < 0.0001), mean central retinal thickness decreased significantly from 439 +/- 45 [mu]m to 296 +/- 49 [mu]m (P < 0.0001), and intraocular pressure changed significantly (P = 0.02) from 14.63 +/- 1.19 to 16 +/- 0.93. In no case postoperative hypotony or other complication was observed. Conclusion: A single injection of the 0.7 mg dexamethasone intravitreal implant resulted effective in the treatment of refractory macular edema secondary to combined cataract extraction and vitrectomy for macular pucker removal allowing a stable visual acuity recovery

Non-local density correlations as signal of Hawking radiation in BEC acoustic black holes

We have used the analogy between gravitational systems and non-homogeneous fluid flows to calculate the density-density correlation function of an atomic Bose-Einstein condensate in the presence of an acoustic black hole. The emission of correlated pairs of phonons by Hawking-like process results into a peculiar long-range density correlation. Quantitative estimations of the effect are provided for realistic experimental configurations.Comment: Strongly revised version. 5 pages, 3 eps figure