56 research outputs found
Exact Multiplicities in the Three-Anyon Spectrum
Using the symmetry properties of the three-anyon spectrum, we obtain exactly
the multiplicities of states with given energy and angular momentum. The
results are shown to be in agreement with the proper quantum mechanical and
semiclassical considerations, and the unexplained points are indicated.Comment: 16 pages plus 3 postscript figures, Kiev Institute for Theoretical
Physics preprint ITP-93-32
Implementing a sectional scheme for early aerosol growth from new particle formation in the Norwegian Earth System Model v2 : comparison to observations and climate impacts
Aerosol-cloud interactions contribute to a large portion of the spread in estimates of climate forcing, climate sensitivity and future projections. An important part of this uncertainty is how much new particle formation (NPF) contributes to cloud condensation nuclei (CCN) and, furthermore, how this changes with changes in anthropogenic emissions. Incorporating NPF and early growth in Earth system models (ESMs) is, however, challenging due to uncertain parameters (e.g. participating vapours), structural issues (numerical description of growth from similar to 1 to similar to 100 nm) and the large scale of an ESM grid compared to the NPF scale. A common approach in ESMs is to represent the particle size distribution by a certain number of log-normal modes. Sectional schemes, on the other hand, in which the size distribution is represented by bins, are considered closer to first principles because they do not make an a priori assumption about the size distribution. In order to improve the representation of early growth, we have implemented a sectional scheme for the smallest particles (5-39.6 nm diameter) in the Norwegian Earth System Model (NorESM), feeding particles into the original aerosol scheme. This is, to our knowledge, the first time such an approach has been tried. We find that including the sectional scheme for early growth improves the aerosol number concentration in the model when comparing against observations, particularly in the 50-100 nm diameter range. Furthermore, we find that the model with the sectional scheme produces much fewer particles than the original scheme in polluted regions, while it produces more in remote regions and the free troposphere, indicating a potential impact on the estimated aerosol forcing. Finally, we analyse the effect on cloud-aerosol interactions and find that the effect of changes in NPF efficiency on clouds is highly heterogeneous in space. While in remote regions, more efficient NPF leads to higher cloud droplet number concentration (CDNC), in polluted regions the opposite is in fact the case.Peer reviewe
Quantum Mechanics and Thermodynamics of Particles with Distance Dependent Statistics
The general notion of distance dependent statistics in anyon-like systems is
discussed. The two-body problem for such statistics is considered, the general
formula for the second virial coefficient is derived and it is shown that in
the limiting cases it reproduces the known results for ideal anyons.Comment: 9 pages, LATEX Kiev Institute for Theoretical Physics preprint
ITP-93-5E, January 199
Energy Spectrum of Anyons in a Magnetic Field
For the many-anyon system in external magnetic field, we derive the energy
spectrum as an exact solution of the quantum eigenvalue problem with particular
topological constraints. Our results agree with the numerical spectra recently
obtained for the 3- and the 4-anyon systems.Comment: 11 pages in Plain LaTeX (plus 4 figures available on request), DFPD
92/TH/4
Baryonic and Gluonic Correlators in Hot QCD
We extend our earlier work on static color singlet correlators in high T QCD
(DeTar correlators) to baryonic and gluonic sources, and estimate the
corresponding screening masses using the dimensionally reduced theory. We
discuss spin and polarization dependence of meson and baryon masses in the limit, and possible nonperturbative effects at
non-asymptotic temperatures.Comment: 20 pages, USITP-94-1 (SUNY-NTG-93-12
BVOC-aerosol-climate feedbacks investigated using NorESM
Both higher temperatures and increased CO2 concentrations are (separately) expected to increase the emissions of biogenic volatile organic compounds (BVOCs). This has been proposed to initiate negative climate feedback mechanisms through increased formation of secondary organic aerosol (SOA). More SOA can make the clouds more reflective, which can provide a cooling. Furthermore, the increase in SOA formation has also been proposed to lead to increased aerosol scattering, resulting in an increase in diffuse radiation. This could boost gross primary production (GPP) and further increase BVOC emissions. In this study, we have used the Norwegian Earth System Model (NorESM) to investigate both these feedback mechanisms. Three sets of experiments were set up to quantify the feedback with respect to (1) doubling the CO2, (2) increasing temperatures corresponding to a doubling of CO2 and (3) the combined effect of both doubling CO2 and a warmer climate. For each of these experiments, we ran two simulations, with identical setups, except for the BVOC emissions. One simulation was run with interactive BVOC emissions, allowing the BVOC emissions to respond to changes in CO2 and/or climate. In the other simulation, the BVOC emissions were fixed at present-day conditions, essentially turning the feedback off. The comparison of these two simulations enables us to investigate each step along the feedback as well as estimate their overall relevance for the future climate. We find that the BVOC feedback can have a significant impact on the climate. The annual global BVOC emissions are up to 63 % higher when the feedback is turned on compared to when the feedback is turned off, with the largest response when both CO2 and climate are changed. The higher BVOC levels lead to the formation of more SOA mass (max 53 %) and result in more particles through increased new particle formation as well as larger particles through increased condensation. The corresponding changes in the cloud properties lead to a -0.43 W m(-2) stronger net cloud forcing. This effect becomes about 50 % stronger when the model is run with reduced anthropogenic aerosol emissions, indicating that the feedback will become even more important as we decrease aerosol and precursor emissions. We do not find a boost in GPP due to increased aerosol scattering on a global scale. Instead, the fate of the GPP seems to be controlled by the BVOC effects on the clouds. However, the higher aerosol scattering associated with the higher BVOC emissions is found to also contribute with a potentially important enhanced negative direct forcing (-0.06 W m(-2)). The global total aerosol forcing associated with the feedback is -0.49 W m(-2), indicating that it has the potential to offset about 13 % of the forcing associated with a doubling of CO2.Peer reviewe
Short- and long-term stratospheric impact of smoke from the 2019–2020 Australian wildfires
At the end of December 2019 and beginning of 2020,
massive firestorms in Australia formed pyrocumulonimbus clouds (pyroCbs) that
acted like enormous smokestacks, pumping smoke to the upper troposphere and
stratosphere. We study the smoke with data from four satellite-based
sensors: the aerosol observation platforms CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization), OMPS-LP (Ozone Mapping and Profiler Suite Limb Profiler), and OMPS-NM (Ozone Mapping and Profiler Suite Nadir Mapper) and
water vapor retrievals from MLS (Microwave Limb Sounder). Smoke was lofted to the upper troposphere
and stratosphere during two events and spread almost exclusively within the
extratropics. Smoke from the first event, starting 29 December, was injected
directly into the stratosphere by pyroCbs, causing a rapid initial increase
in AOD (aerosol optical depth). CALIOP identifies a rapid decline in this stratospheric smoke
(half-life: 10 d), not captured in previous studies of the Australian
fires, indicating photochemical processing of organic aerosol. This decay
rate is in line with model predictions of mid-tropospheric organic aerosol
loss by photolytic removal and is in agreement with our estimates of decay
rates after the North American fires in August 2017. PyroCbs from the second
event, 4 January, injected small amounts of smoke directly into the
stratosphere. Large amounts of smoke were injected to the upper troposphere,
from where it ascended into the stratosphere during several weeks, forming a
second peak in the aerosol load. Hence, we find that pyroCbs can impact the
stratospheric aerosol load both via direct injection to the stratosphere
and through injection of smoke to the upper troposphere from where the smoke
ascends into the stratosphere. The stratospheric AOD from the second-event
fires decreased more slowly than the AOD from the first event, likely due to a
combination of photolytic loss starting already in the troposphere and
continued supply of smoke from the upper troposphere offsetting the loss
rate. Together these injections yielded a major increase in the aerosol load
for almost 1 year.</p
Classical Dynamics of Anyons and the Quantum Spectrum
In this paper we show that (a) all the known exact solutions of the problem
of N-anyons in oscillator potential precisely arise from the collective degrees
of freedom, (b) the system is pseudo-integrable ala Richens and Berry. We
conclude that the exact solutions are trivial thermodynamically as well as
dynamically.Comment: 19 pages, ReVTeX, IMSc/93/0
Haldane exclusion statistics and second virial coefficient
We show that Haldanes new definition of statistics, when generalised to
infinite dimensional Hilbert spaces, is equal to the high temperature limit of
the second virial coefficient. We thus show that this exclusion statistics
parameter, g , of anyons is non-trivial and is completely determined by its
exchange statistics parameter . We also compute g for quasiparticles in
the Luttinger model and show that it is equal to .Comment: 11 pages, REVTEX 3.
Exact Wavefunctions for non-Abelian Chern-Simons Particles
Exact wavefunctions for N non-Abelian Chern-Simons (NACS) particles are
obtained by the ladder operator approach. The same method has previously been
applied to construct exact wavefunctions for multi-anyon systems. The two
distinct base states of the NACS particles that we use are multi-valued and are
defined in terms of path ordered line integrals. Only strings of operators that
preserve the monodromy properties of these base states are allowed to act on
them to generate new states.Comment: 19 pages, CALT-68-187
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