Measurement enhances long-distance Entanglement generation in spin chains with dissipative processes

In this paper, effects of the regular measurements on a noisy channel has been investigated. The strategy introduced by A. Bayat, and Y. Omar [New J. Phys. 17, 103041 (2015)] is followed to suppress dephasing and dissipation effects in a noisy spin channel and generate long distance entanglement by global measurement on the channel. A regular global measurements performed on spin channel weakly coupled to the sender and receiver qubits via $XX$ interaction. This scheme is applied for the dephasing and dissipation in non-zero temperature processes separately and the results show that amounts of achieved entanglement enhanced rather than the no-measurement approach.Comment: 6 pages, 6 figures, Comments welcom

Universal feedback control of two-qubit entanglement

We consider two-qubit undergoing local dissipation and subject to local driving. We then determine the optimal Markovian feedback action to preserve initial entanglement as well as to create stationary entanglement with the help of an XY interaction Hamiltonian. Such feedback actions are worked out in a way not depending on the initial two-qubit state, whence called universal.Comment: 10 pages, 6 figure

Stationary and uniform entanglement distribution in qubit networks with quasi-local dissipation

We consider qubit networks where adjacent qubits besides interacting via XY-coupling, also dissipate into the same environment. The steady states are computed exactly for all network sizes and topologies, showing that they are always symmetric under permutation of network sites, leading to a uniform distribution of the stationary entanglement across the network. The maximum entanglement between two arbitrary qubits is shown to depend only on the total number of qubits in the network, and scales linearly with it. A possible physical realization by means of an array of doped cavities is discussed for the case of a linear chain.Comment: 6 pages, comments welcome. v2: published version with typos corrected and updated bibliograph

Electromagnetic field quantization in the presence of a moving nano-particle

An appropriate Lagrangian is considered for a system comprising a moving nanoparticle in a semi-infinite space, and the electromagnetic and matter fields are quantized. Through an analysis of the absorbed power radiation, it is demonstrated that the quantum friction experienced by high-velocity nanoparticles can be identified as a dissipative term in the radiation power of the nanoparticle. The absorbed power radiation for a moving nanoparticle is derived and compared with that of a static one. By considering two different temperature scenarios, it is explicitly shown that the absorbed power radiation for a moving nanoparticle always contains a negative term in its power spectrum, which can be attributed to the power lost due to non-contact quantum friction

Film-ovojnica smjese pektina, kitozana i Eudragita® RS za bimodalno oslobađanje lijeka iz peleta s teofilinom: Priprava i evaluacija

Pellets containing theophylline as a model drug and microcrystalline cellulose, in a ratio of 6:4, were prepared by extrusion-spheronization method. The pellets were coated with Eudragit® RS aqueous dispersions, containing various amounts of pectin-chitosan complex and different coating mass gains, using a fluidized-bed apparatus. Twelve formulations were developed, which differed in two factors: coating mass gain (10, 15 and 20%, m/m) and amount of pectin-chitosan complex (5, 10, 15 and 20%, m/m). Drug release studies were conducted using the USP apparatus Ι (basket) in dissolution media, mimicking the conditions pertaining in the stomach, small intestine and colon, respectively. Studies have shown that drug release rate and pattern were dependent on both two mentioned factors. Some formulations showed bimodal and burst drug release, being triggered in the colonic medium by the action of pectinolytic enzymes. In formulations with 15 or 20% (m/m) of coating mass gain and 5 or 10% (m/m) of pectin-chitosan amount, the burst drug release was eliminated and replaced by lag phase of drug release. In viewpoint of burst drug release in the colonic medium, formulations with 20% (m/m) of coating mass gain and 15 or 20% (m/m) of pectin-chitosan amount were found to be better than the other formulations. Studies on the surface SEMs of uncoated and coated pellets show that after coating, coated pellets became smoother and exposure to pectinolytic enzymes in the colonic medium may result in surface erosion.Pelete s teofilinom kao modelnim lijekom i mikrokristaliničnom celulozom u omjeru 6:4 pripravljeni su metodom ekstruzije i sferonizacije. Pelete su presvučene vodenom disperzijom Eudragita® RS koja sadrži različite količine kompleksa pektina i kitozana i različite mase ovojnice, koristeći uređaj za fluidizaciju. Pripravljeno je 12 peleta koji se razlikuju po masi ovojnice (10, 15 i 20%, m/m) i udjelu kompleksa pektina i kitozana (5, 10, 15 i 20%, m/m). Oslobađanje ljekovite tvari proučavano je u USP aparaturi Ι (s košaricama) u medijima koji odgovaraju pH probavnog sustava. Dobiveni rezultati ukazuju da brzina i način oslobađanja lijeka ovisi o oba spomenuta parametra. Iz nekih pripravaka oslobađanje je bimodalno, a posljedica je djelovanja pektinolitičkih enzima iz kolona. U pripravcima u kojima je udio ovojnice 15 ili 20% (m/m), a udio pektin-kitozana 5 ili 10% (m/m) oslobađanje je bilo polagano. Najbolji pripravci za naglo oslobađanje u pH mediju područja kolona sadržavali su 20% (m/m) ovojnice i 15 ili 20% (m/m) pektin-kitozana. Proučavanje obloženih i neobloženih peleta SEM metodom pokazuje da obložene pelete imaju glatkiju površinu, koja erodira djelovanjem pektinolitičkih enzima