236 research outputs found
Oxidation of sulphur dioxide in water droplets in the presence of ammonia
SO2 oxidation by oxygen in monodisperse water droplets was studied in a cylindrical chamber, without and in the presence of ammonia. The range of SO2 concentration was from about 1022 to 5 ppmv, while the NH3 input concentration was kept constant at about 4.731022 ppmv. The contact time between gases and droplets was 210 s. The experimental results were compared with the theoretical
values predicted by the kinetics of Larson et al. (Atmos. Environ., 12 (1978) 1597) and McKay (Atmos. Environ., 5 (1971) 7). Much higher sulphate concentrations were
obtained in experiments run in the presence of NH3, as opposed to those without NH3. The experimental results agree with the values predicted by McKay’s kinetics and are higher than Larson’s
SO2 oxidation in supercooled droplets in the presence of O2
Sulphur dioxide oxidation in supercooled monodisperse droplets at T4213 7C was studied in the presence of oxygen. The SO2 concentration was found to range from 0.08 to 7.1 ppmv and the contact time between gases and droplets was
210 s. The experimental results showed that sulphate concentration due to SO2 oxidation is independent of temperature, i.e. the increase of SO2 solubility in the
liquid phase balances the rate constant decrease of the oxidation reaction. Following McKay’s kinetics (Atmos. Environ., 5 (1971) 7), we calculated the rate constant at
T4213 7C and the activation energy. A comparison was made between experimental S(VI) oxidation concentrations due to oxygen and theoretical oxidation values due to O3, H2O2 and oxygen in the presence of catalyzers (Fe31, Mn21)
Infinite Randomness Phases and Entanglement Entropy of the Disordered Golden Chain
Topological insulators supporting non-abelian anyonic excitations are at the
center of attention as candidates for topological quantum computation. In this
paper, we analyze the ground-state properties of disordered non-abelian anyonic
chains. The resemblance of fusion rules of non-abelian anyons and real space
decimation strongly suggests that disordered chains of such anyons generically
exhibit infinite-randomness phases. Concentrating on the disordered golden
chain model with nearest-neighbor coupling, we show that Fibonacci anyons with
the fusion rule exhibit two
infinite-randomness phases: a random-singlet phase when all bonds prefer the
trivial fusion channel, and a mixed phase which occurs whenever a finite
density of bonds prefers the fusion channel. Real space RG analysis
shows that the random-singlet fixed point is unstable to the mixed fixed point.
By analyzing the entanglement entropy of the mixed phase, we find its effective
central charge, and find that it increases along the RG flow from the random
singlet point, thus ruling out a c-theorem for the effective central charge.Comment: 16 page
Entanglement between particle partitions in itinerant many-particle states
We review `particle partitioning entanglement' for itinerant many-particle
systems. This is defined as the entanglement between two subsets of particles
making up the system. We identify generic features and mechanisms of particle
entanglement that are valid over whole classes of itinerant quantum systems. We
formulate the general structure of particle entanglement in many-fermion ground
states, analogous to the `area law' for the more usually studied entanglement
between spatial regions. Basic properties of particle entanglement are first
elucidated by considering relatively simple itinerant models. We then review
particle-partitioning entanglement in quantum states with more intricate
physics, such as anyonic models and quantum Hall states.Comment: review, about 20 pages. Version 2 has minor revisions
Correlation amplitude and entanglement entropy in random spin chains
Using strong-disorder renormalization group, numerical exact diagonalization,
and quantum Monte Carlo methods, we revisit the random antiferromagnetic XXZ
spin-1/2 chain focusing on the long-length and ground-state behavior of the
average time-independent spin-spin correlation function C(l)=\upsilon
l^{-\eta}. In addition to the well-known universal (disorder-independent)
power-law exponent \eta=2, we find interesting universal features displayed by
the prefactor \upsilon=\upsilon_o/3, if l is odd, and \upsilon=\upsilon_e/3,
otherwise. Although \upsilon_o and \upsilon_e are nonuniversal (disorder
dependent) and distinct in magnitude, the combination \upsilon_o + \upsilon_e =
-1/4 is universal if C is computed along the symmetric (longitudinal) axis. The
origin of the nonuniversalities of the prefactors is discussed in the
renormalization-group framework where a solvable toy model is considered.
Moreover, we relate the average correlation function with the average
entanglement entropy, whose amplitude has been recently shown to be universal.
The nonuniversalities of the prefactors are shown to contribute only to surface
terms of the entropy. Finally, we discuss the experimental relevance of our
results by computing the structure factor whose scaling properties,
interestingly, depend on the correlation prefactors.Comment: v1: 16 pages, 15 figures; v2: 17 pages, improved discussions and
statistics, references added, published versio
Fractional Laplacian in Bounded Domains
The fractional Laplacian operator, ,
appears in a wide class of physical systems, including L\'evy flights and
stochastic interfaces. In this paper, we provide a discretized version of this
operator which is well suited to deal with boundary conditions on a finite
interval. The implementation of boundary conditions is justified by appealing
to two physical models, namely hopping particles and elastic springs. The
eigenvalues and eigenfunctions in a bounded domain are then obtained
numerically for different boundary conditions. Some analytical results
concerning the structure of the eigenvalues spectrum are also obtained.Comment: 11 pages, 11 figure
One-Dimensional Impenetrable Anyons in Thermal Equilibrium. II. Determinant Representation for the Dynamic Correlation Functions
We have obtained a determinant representation for the time- and
temperature-dependent field-field correlation function of the impenetrable
Lieb-Liniger gas of anyons through direct summation of the form factors. In the
static case, the obtained results are shown to be equivalent to those that
follow from the anyonic generalization of Lenard's formula.Comment: 16 pages, RevTeX
Entanglement Entropy in the Calogero-Sutherland Model
We investigate the entanglement entropy between two subsets of particles in
the ground state of the Calogero-Sutherland model. By using the duality
relations of the Jack symmetric polynomials, we obtain exact expressions for
both the reduced density matrix and the entanglement entropy in the limit of an
infinite number of particles traced out. From these results, we obtain an upper
bound value of the entanglement entropy. This upper bound has a clear
interpretation in terms of fractional exclusion statistics.Comment: 14 pages, 3figures, references adde
One-dimensional anyons with competing -function and derivative -function potentials
We propose an exactly solvable model of one-dimensional anyons with competing
-function and derivative -function interaction potentials. The
Bethe ansatz equations are derived in terms of the -particle sector for the
quantum anyonic field model of the generalized derivative nonlinear
Schr\"{o}dinger equation. This more general anyon model exhibits richer physics
than that of the recently studied one-dimensional model of -function
interacting anyons. We show that the anyonic signature is inextricably related
to the velocities of the colliding particles and the pairwise dynamical
interaction between particles.Comment: 9 pages, 2 figures, minor changes, references update
Supersymmetric Model of Spin-1/2 Fermions on a Chain
In recent work, N=2 supersymmetry has been proposed as a tool for the
analysis of itinerant, correlated fermions on a lattice. In this paper we
extend these considerations to the case of lattice fermions with spin 1/2 . We
introduce a model for correlated spin-1/2 fermions with a manifest N=4
supersymmetry, and analyze its properties. The supersymmetric ground states
that we find represent holes in an anti-ferromagnetic background.Comment: 15 pages, 10 eps figure
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