498 research outputs found
Heterodi- (Fe, Pd/Pt) and heterotrimetallic (Fe2, Pd) complexes derived from 4-(ferrocenylmethyl)-N-(2-methoxyethyl)-3,5-diphenylpyrazole as potential antitumoral agents
The study of the reactivity of the pyrazole derivative 1-[MeO-(CH2)2]-3,5-Ph2-4-(CH2Fc) (C3N2) (1, Fc = ferrocenyl) with Na2[PdCl4], Pd(OAc)2, and [MCl2(dmso)2] (M = Pd or Pt,dmso = dimethyl sulfoxide) has allowed us to isolate trans-[Pd{κ-N-(1-{MeO(CH2)2}-3,5-Ph2-4-{CH2Fc} {C3N2})}2Cl2] (2), [Pd{κ2-C,N(1-{MeO(CH2)2}-3-{C6H4}-5-Ph-{C3N2})}{κ-N-(1-{MeO(CH2)2}-3,5-Ph2-4-{CH2Fc} {C3N2})}Cl] (3), [Pd{κ2-C,N(1-{MeO(CH2)2}-3-{C6H4}-4-{CH2Fc}-5-Ph-{C3N2})}Cl-(PPh3)] (4), and the trans (5) and cis (6) isomers of [Pt{κ-N-(1-{MeO(CH2)2}-3,5-Ph24-{CH2Fc} {C3N2})}Cl2(dmso)]. Compound 1 acts as a N (in 2, 5, and 6) or (C,N) donor ligand (in 4) and shows both binding modes in 3. The cytotoxic assessment of 1 6 against MCF7, MDA-MB231 (breast), and HCT-116 (colon) cancer cell lines reveal that (1) 1 is more potent than 1-[MeO(CH2)2]-3,5-Ph2-(C3HN2) (V), (2) 2 6 have cytotoxic activity, (3) 2 and 3 are less active than 4 6, and (4) 6 is the most potent compound against the three cancer cell lines
Revisiting Absorbing Phase Transition in Energy Exchange Models
A recent study of conserved Manna model, with both discrete and continuous
variable, indicates that absorbing phase transitions therein belong to the
directed percolation (DP) universality class. In this context we revisit
critical behaviour in energy exchange models with a threshold. Contrary to the
previous claims [PRE 83, 061130 (2011), arXiv:1102.1631], our results indicate
that both the maximal and minimal versions of this model belong to the DP
class.Comment: 8 pages, 7 eps figure
Constructing Exactly Solvable Pseudo-hermitian Many-particle Quantum Systems by Isospectral Deformation
A class of non-Dirac-hermitian many-particle quantum systems admitting
entirely real spectra and unitary time-evolution is presented. These quantum
models are isospectral with Dirac-hermitian systems and are exactly solvable.
The general method involves a realization of the basic canonical commutation
relations defining the quantum system in terms of operators those are hermitian
with respect to a pre-determined positive definite metric in the Hilbert space.
Appropriate combinations of these operators result in a large number of
pseudo-hermitian quantum systems admitting entirely real spectra and unitary
time evolution. Examples of a pseudo-hermitian rational Calogero model and XXZ
spin-chain are considered.Comment: To appear in the Special Issue PHHQP 2010, International Journal of
Theoretical Physics; 16 pages, LateX, no figur
A Unified Algebraic Approach to Few and Many-Body Correlated Systems
The present article is an extended version of the paper {\it Phys. Rev.} {\bf
B 59}, R2490 (1999), where, we have established the equivalence of the
Calogero-Sutherland model to decoupled oscillators. Here, we first employ the
same approach for finding the eigenstates of a large class of Hamiltonians,
dealing with correlated systems. A number of few and many-body interacting
models are studied and the relationship between their respective Hilbert
spaces, with that of oscillators, is found. This connection is then used to
obtain the spectrum generating algebras for these systems and make an algebraic
statement about correlated systems. The procedure to generate new solvable
interacting models is outlined. We then point out the inadequacies of the
present technique and make use of a novel method for solving linear
differential equations to diagonalize the Sutherland model and establish a
precise connection between this correlated system's wave functions, with those
of the free particles on a circle. In the process, we obtain a new expression
for the Jack polynomials. In two dimensions, we analyze the Hamiltonian having
Laughlin wave function as the ground-state and point out the natural emergence
of the underlying linear symmetry in this approach.Comment: 18 pages, Revtex format, To appear in Physical Review
An explicit realization of fractional statistics in one dimension
An explicit realization of anyons is provided, using the three-body Calogero
model. The fact that in the coupling domain, , the angular spectrum
can have a band structure, leads to the manifestation of the desired phase in
the wave function, under the exchange of the paticles. Concurrently, the
momentum corresponding to the angular variable is quantized, exactly akin to
the relative angular momentum quantization in two dimensional anyonic systemComment: 12 page
Inequivalent quantization of the rational Calogero model with a Coulomb type interaction
We consider the inequivalent quantizations of a -body rational Calogero
model with a Coulomb type interaction. It is shown that for certain range of
the coupling constants, this system admits a one-parameter family of
self-adjoint extensions. We analyze both the bound and scattering state sectors
and find novel solutions of this model. We also find the ladder operators for
this system, with which the previously known solutions can be constructed.Comment: 15 pages, 3 figures, revtex4, typos corrected, to appear in EPJ
Spatio-temporal dynamics of quantum-well excitons
We investigate the lateral transport of excitons in ZnSe quantum wells by
using time-resolved micro-photoluminescence enhanced by the introduction of a
solid immersion lens. The spatial and temporal resolutions are 200 nm and 5 ps,
respectively. Strong deviation from classical diffusion is observed up to 400
ps. This feature is attributed to the hot-exciton effects, consistent with
previous experiments under cw excitation. The coupled transport-relaxation
process of hot excitons is modelled by Monte Carlo simulation. We prove that
two basic assumptions typically accepted in photoluminescence investigations on
excitonic transport, namely (i) the classical diffusion model as well as (ii)
the equivalence between the temporal and spatial evolution of the exciton
population and of the measured photoluminescence, are not valid for
low-temperature experiments.Comment: 8 pages, 6 figure
Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions at TeV
The elliptic, , triangular, , and quadrangular, , azimuthal
anisotropic flow coefficients are measured for unidentified charged particles,
pions and (anti-)protons in Pb-Pb collisions at TeV
with the ALICE detector at the Large Hadron Collider. Results obtained with the
event plane and four-particle cumulant methods are reported for the
pseudo-rapidity range at different collision centralities and as a
function of transverse momentum, , out to GeV/.
The observed non-zero elliptic and triangular flow depends only weakly on
transverse momentum for GeV/. The small dependence
of the difference between elliptic flow results obtained from the event plane
and four-particle cumulant methods suggests a common origin of flow
fluctuations up to GeV/. The magnitude of the (anti-)proton
elliptic and triangular flow is larger than that of pions out to at least
GeV/ indicating that the particle type dependence persists out
to high .Comment: 16 pages, 5 captioned figures, authors from page 11, published
version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/186
Centrality dependence of charged particle production at large transverse momentum in Pb-Pb collisions at TeV
The inclusive transverse momentum () distributions of primary
charged particles are measured in the pseudo-rapidity range as a
function of event centrality in Pb-Pb collisions at
TeV with ALICE at the LHC. The data are presented in the range
GeV/ for nine centrality intervals from 70-80% to 0-5%.
The Pb-Pb spectra are presented in terms of the nuclear modification factor
using a pp reference spectrum measured at the same collision
energy. We observe that the suppression of high- particles strongly
depends on event centrality. In central collisions (0-5%) the yield is most
suppressed with at -7 GeV/. Above
GeV/, there is a significant rise in the nuclear modification
factor, which reaches for GeV/. In
peripheral collisions (70-80%), the suppression is weaker with almost independently of . The measured nuclear
modification factors are compared to other measurements and model calculations.Comment: 17 pages, 4 captioned figures, 2 tables, authors from page 12,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/284
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