Francesco Paolo Mancini

Topology-induced spatial Bose–Einstein condensation for bosons on star-shaped optical networks

New coherent states may be induced by pertinently engineering the topology of a network. As an example, we consider the properties of non-interacting bosons on a star network, which may be realized with a dilute atomic gas in a star-shaped deep optical lattice. The ground state is localized around the star centre and it is macroscopically occupied below the Bose–Einstein condensation temperature Tc. We show that Tc depends only on the number of the star arms and on the Josephson energy of the bosonic Josephson junctions and that the non-condensate fraction is simply given by the reduced temperature T/Tc.

Emery vs. Hubbard model for cuprate superconductors: a composite operator method study

AbstractnWithin the composite operator method (COM), we report the solution of the Emery modeln(also known as p-d or three band model), which isnrelevant for the cuprate high-Tcnsuperconductors. We also discuss the relevance of the often-neglected direct oxygen-oxygennhopping for a more accurate, sometimes unique, description of this class of materials. Thenbenchmark of the solution is performed by comparing our results with the available quantumnMonte Carlo ones. Both single-particle and thermodynamic properties of the model arenstudied in detail. Our solution features a metal-insulator transition at half filling. Thenresulting metal-insulator phase diagram agrees qualitatively very well with the onenobtained within dynamical mean-field theory. We discuss the type of transitionn(Mott-Hubbard (MH) or charge-transfer (CT)) for the microscopic (abxa0initio) parameternrange relevant for cuprates getting, as expected a CT type. The emerging single-particlenscenario clearly suggests a very close relation between the relevant sub-bands of thenthree- (Emery) and the single-band (Hubbard) models, thus providing an independent andnnon-perturbative proof of the validity of the mapping between the two models for the modelnparameters optimal to describe cuprates. Such a result confirms the emergence of thenZhang-Rice scenario, which has been recently questioned. We also report the behavior ofnthe specific heat and of the entropy as functions of the temperature on varying the modelnparameters as these quantities, more than any other, depend on and, consequently, revealnthe most relevant energy scales of the system.

Extended Hubbard model in the presence of a magnetic field

Within the Green’s function and equations of motion formalism it is possible to exactly solve a large class of models useful for the study of strongly correlated systems. Here, we present the exact solution of the one-dimensional extended Hubbard model with on-site U and first nearest neighbor repulsive V interactions in the presence of an external magnetic field h, in the narrow band limit. At zero temperature our results establish the existence of four phases in the three-dimensional space (U, n, h) – n is the filling – with relative phase transitions, as well as different types of charge ordering. The magnetic field may dramatically affect the behavior of thermodynamic quantities, inducing, for instance, magnetization plateaus in the magnetization curves, and a change from a single to a double-peak tructure in the specific heat. According to the value of the particle density, we find one or two critical fields, marking the beginning of full or partial polarization. A detailed study of several thermodynamic quantities is also presented at finite temperature.

Phase diagram of Josephson junction arrays with capacitive disorder

We study the phase diagram at finite temperature of Josephson junction arrays with capacitive disorder (i.e., random offset charges and/or random charging energies): in the limit of large particle numbers per junction, this is a remarkable physical realization of the disordered boson Hubbard model. By using a mean-field approximation, we compute the average free energy and the equation for the phase boundary line between the insulating and superconducting phases. We find that the Mott-insulating lobe structure disappears for large variance

Intra-articular administration of lidocaine plus adrenaline in dogs: Pharmacokinetic profile and evaluation of toxicity in vivo and in vitro

(ensuremath{sigma}ensuremath{gtrsim}e)

Role of the attractive intersite interaction in the extended Hubbard model

of the offset charges probability distribution. Further, with nearest-neighbor interactions, the insulating lobe around

TOPOLOGY INDUCED MACROSCOPIC QUANTUM COHERENCE IN JOSEPHSON JUNCTION NETWORKS

q=e

Sympathetic innervation of the suprasesamoidean region of the deep digital flexor tendon in the forelimbs of horses.

is destroyed even for small values of

A pool of peptides extracted from wheat bud chromatin inhibits tumor cell growth by causing defective DNA synthesis

ensuremath{sigma}.

BEC in a star‐comb graph

In the case of random charging energies, until the variance of the distribution reaches some critical value the superconducting phase increases in comparison to the situation in which all self-capacitances are equal.