36,133 research outputs found

    A characterization of positive linear maps and criteria of entanglement for quantum states

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    Let HH and KK be (finite or infinite dimensional) complex Hilbert spaces. A characterization of positive completely bounded normal linear maps from B(H){\mathcal B}(H) into B(K){\mathcal B}(K) is given, which particularly gives a characterization of positive elementary operators including all positive linear maps between matrix algebras. This characterization is then applied give a representation of quantum channels (operations) between infinite-dimensional systems. A necessary and sufficient criterion of separability is give which shows that a state ρ\rho on HKH\otimes K is separable if and only if (ΦI)ρ0(\Phi\otimes I)\rho\geq 0 for all positive finite rank elementary operators Φ\Phi. Examples of NCP and indecomposable positive linear maps are given and are used to recognize some entangled states that cannot be recognized by the PPT criterion and the realignment criterion.Comment: 20 page

    Antioxidant and Antitumor Activity of Indonesian Herbal Ingredients

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    The present study was to aimed to evaluated and compare in vitro antioxidant activities of 2 Indonesian herbal ingredients (A and B), determined total phenol content., cytotoxic and apoptosis induction activities on HL-60 cells. These data were providing some useful information for people healthy dietary and the new potential application of natural antioxidant containing food materials in functional foods and also as new cancer therapeutics promising candidates. The parameters were total antioxidant activity, amount of total cytotoxic effect on the growth of human promyelocytic leukemia cells (HL-60). Statistical comparison was perform with Student's t-test at p<0.05. The correlation coefficient (r2) between the parameters tested was established by regression analysis. The scavenging effect of extracts herbal on DPPH radicals increased from 0.3-1.5 mg/ml, where is sample A 14.33% to 64.29% and sample B 9.09% to 57.53% was obtained. High content of total phenol compounds were in sample A (21.72 mg GAE/g), lower amounts were in sample B (17.53 mg GAE/g). Apoptosis of HL-60 cells from the morphological changes side (chromatin condensation). Chromatin condensation, a specific and distinct feature of apoptotic cells, was found in the majority of treated cells. The results indicated that the cell death receptor pathway was involved in the apoptosis induced by Indonesian herbal extracts

    Spin-current injection and detection in strongly correlated organic conductor

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    Spin-current injection into an organic semiconductor κ-(BEDT-TTF)2Cu[N(CN)2]Br\rm{\kappa\text{-}(BEDT\text{-}TTF)_2Cu[N(CN)_2]Br} film induced by the spin pumping from an yttrium iron garnet (YIG) film. When magnetization dynamics in the YIG film is excited by ferromagnetic or spin-wave resonance, a voltage signal was found to appear in the κ-(BEDT-TTF)2Cu[N(CN)2]Br\rm{\kappa\text{-}(BEDT\text{-}TTF)_2Cu[N(CN)_2]Br} film. Magnetic-field-angle dependence measurements indicate that the voltage signal is governed by the inverse spin Hall effect in κ-(BEDT-TTF)2Cu[N(CN)2]Br\rm{\kappa\text{-}(BEDT\text{-}TTF)_2Cu[N(CN)_2]Br}. We found that the voltage signal in the κ-(BEDT-TTF)2Cu[N(CN)2]Br\rm{\kappa\text{-}(BEDT\text{-}TTF)_2Cu[N(CN)_2]Br}/YIG system is critically suppressed around 80 K, around which magnetic and/or glass transitions occur, implying that the efficiency of the spin-current injection is suppressed by fluctuations which critically enhanced near the transitions

    On Singularity Formation of a Nonlinear Nonlocal System

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    We investigate the singularity formation of a nonlinear nonlocal system. This nonlocal system is a simplified one-dimensional system of the 3D model that was recently proposed by Hou and Lei in [13] for axisymmetric 3D incompressible Navier-Stokes equations with swirl. The main difference between the 3D model of Hou and Lei and the reformulated 3D Navier-Stokes equations is that the convection term is neglected in the 3D model. In the nonlocal system we consider in this paper, we replace the Riesz operator in the 3D model by the Hilbert transform. One of the main results of this paper is that we prove rigorously the finite time singularity formation of the nonlocal system for a large class of smooth initial data with finite energy. We also prove the global regularity for a class of smooth initial data. Numerical results will be presented to demonstrate the asymptotically self-similar blow-up of the solution. The blowup rate of the self-similar singularity of the nonlocal system is similar to that of the 3D model.Comment: 28 pages, 9 figure

    Desperately Seeking Non-Standard Phases via Direct CP Violation in bsgb\to sg^\ast Process

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    Attributing the recent CLEO discovery of Bη+XsB \to \eta' + X_s to originate (primarily) from the fragmentation of an off-shell gluon (gg^*) via bs+gb \to s + g^*, gg+ηg^* \to g + \eta', we emphasize that many such states (XgX_g) should materialize. Indeed the hadronic fragments (XgX_g) of gg^* states are closely related to those seen in ψγ(ϕ,ω)+Xg\psi \to \gamma (\phi, \omega) + X_g. A particular final state of considerable interest is Xg=K+KX_g=K^+K^-. Signals from such states in BB decays can be combined to provide a very sensitive search for CP violating phase(s) from non-standard physics. The method should work even if the contribution of these source(s) to the rates is rather small (10\sim10%) to the point that a comparison between theory and experiment may find it extremely difficult to reveal the presence of such a new physics.Comment: 16 pages, 5 figure

    Fermi resonance-algebraic model for molecular vibrational spectra

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    A Fermi resonance-algebraic model is proposed for molecular vibrations, where a U(2) algebra is used for describing the vibrations of each bond, and Fermi resonances between stretching and bending modes are taken into account. The model for a bent molecule XY_2 and a molecule XY_3 is successfully applied to fit the recently observed vibrational spectrum of the water molecule and arsine (AsH_3), respectively, and results are compared with those of other models. Calculations show that algebraic approaches can be used as an effective method for describing molecular vibrations with small standard deviations

    Enhanced bsgb\to sg Decay, Inclusive η\eta^\prime Production, and the Gluon Anomaly

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    The experimental hint of large Bη+XsB\to \eta^\prime + X_s is linked to the bsb\to s penguins via the gluon anomaly. Using running αs\alpha_s in the η\eta^\prime-gg-gg coupling, the standard bsgb\to sg^* penguin alone seems insufficient, calling for the need of dipole bsgb\to sg at 10% level from new physics, which could also resolve the Bs.l.{\cal B}_{s.l.} and charm counting problems. The intereference of standard and new physics contributions may result in direct CP asymmetries at 10% level, which could be observed soon at B Factories.Comment: 12 pages, revtex, 3 figs. (version to appear in Phys. Rev. Lett.

    Necessary and sufficient conditions for local creation of quantum discord

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    We show that a local channel cannot create quantum discord (QD) for zero QD states of size d3d\geq3 if and only if either it is a completely decohering channel or it is a nontrivial isotropic channel. For the qubit case this propertiy is additionally characteristic to the completely decohering channel or the commutativity-preserving unital channel. In particular, the exact forms of the completely decohering channel and the commutativity-preserving unital qubit channel are proposed. Consequently, our results confirm and improve the conjecture proposed by X. Hu et al. for the case of d3d\geq3 and improve the result proposed by A. Streltsov et al. for the qubit case. Furthermore, it is shown that a local channel nullifies QD in any state if and only if it is a completely decohering channel. Based on our results, some protocols of quantum information processing issues associated with QD, especially for the qubit case, would be experimentally accessible.Comment: 8 page

    Dynamical Symmetry Breaking With a Fourth Generation

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    Adding a fourth generation to the Standard Model and assuming it to be valid up to some cutoff \Lambda, we show that electroweak symmetry is broken by radiative corrections due to the fourth generation. The effects of the fourth generation are isolated using a Lagrangian with a genuine scalar without self-interactions at the classical level. For masses of the fourth generation consistent with electroweak precision data (including the B \rightarrow K \pi\ CP asymmetries) we obtain a Higgs mass of the order of a few hundreds GeV and a cutoff \Lambda\ around 1-2 TeV. We study the reliability of the perturbative treatment used to obtain these results taking into account the running of the Yukawa couplings of the fourth quark generation with the aid of the Renormalization Group (RG) equations, finding similar allowed values for the Higgs mass but a slightly lower cut-off due to the breaking of the perturbative regime. Such low cut-off means that the effects of new physics needed to describe electroweak interactions at energy above \Lambda\ should be measurable at the LHC. We use the minimal supersymmetric extension of the standard model with four generations as an explicit example of models realizing the dynamical electroweak symmetry breaking by radiative corrections and containing new physics. Here, the cutoff is replaced by the masses of the squarks and electroweak symmetry breaking by radiative corrections requires the squark masses to be of the order of 1 TeV.Comment: 20 pages, 7 figures. New section adde
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