6,398 research outputs found
Municipal Solid Waste Flow Control in the Post-Carbone World
Garbage will always ultimately be the government\u27s problem. Evolving environmental standards and state and federal policies will continue to require reasoned responses from local governments and municipal solid waste flow control is a vital cog in many jurisdictions\u27 solid waste management solutions. Without flow control of some form, governments\u27 ability to plan and provide for the most environmentally sound and economically acceptable solutions will wane, leaving the public vulnerable to the vagaries of a private market that does not have a duty to protect the public health and safety. The Carbone decision has blunted one of the local governments chief weapons-legislative flow control-and it appears Congress will not supply an adequate answer for many solid waste systems. More than ever, alternatives to legislative flow control will be needed to enable municipalities to fulfill their solid waste duties, to comply with federal and state mandates, and to provide workable, environmentally-sound, long-term solid waste programs serving the interests of the public health and safety. Local governments must act soon by examining these options and deciding which will best serve the public
Detection techniques for tenuous planetary atmospheres Fifth six-month report, 1 Jul. - 30 Dec. 1965
Physical methods description for detection and analysis of tenuous planetary atmospheric component gases, especially water vapo
Scale invariant thermodynamics of a toroidally trapped Bose gas
We consider a system of bosonic atoms in an axially symmetric harmonic trap
augmented with a two dimensional repulsive Gaussian optical potential. We find
an expression for the grand free energy of the system for configurations
ranging from the harmonic trap to the toroidal regime. For large tori we
identify an accessible regime where the ideal gas thermodynamics of the system
are found to be independent of toroidal radius. This property is a consequence
of an invariant extensive volume of the system that we identify analytically in
the regime where the toroidal potential is radially harmonic. In considering
corrections to the scale invariant transition temperature, we find that the
first order interaction shift is the dominant effect in the thermodynamic
limit, and is also scale invariant. We also consider adiabatic loading from the
harmonic to toroidal trap configuration, which we show to have only a small
effect on the condensate fraction of the ideal gas, indicating that loading
into the scale invariant regime may be experimentally practical.Comment: 10 pages, 3 figures, to appear in Phys. Rev. A, typos corrected,
references added, rewritten to emphasize generalized volume. Results
unchange
RKKY Interaction in Graphene from Lattice Green's Function
We study the exchange interaction between two magnetic impurities in
graphene (the RKKY interaction) by directly computing the lattice Green's
function for the tight-binding band structure for the honeycomb lattice. The
method allows us to compute numerically for much larger distances than can
be handled by finite-lattice calculations as well as for small distances. %
avoids the use of a cutoff function often invoked in the literature to curtail
the diverging contributions from the linear bands and yields results that are
valid for all distances. In addition, we rederive the analytical long-distance
behavior of for linearly dispersive bands and find corrections to the
oscillatory factor that were previously missed in the literature. The main
features of the RKKY interaction in graphene are that unlike the behavior of an ordinary 2D metal in the
long-distance limit, in graphene falls off as , shows the -type oscillations with additional phase factors depending on the
direction, and exhibits a ferromagnetic interaction for moments on the same
sublattice and an antiferromagnetic interaction for moments on the opposite
sublattices as required by particle-hole symmetry. The computed with the
full band structure agrees with our analytical results in the long-distance
limit including the oscillatory factors with the additional phases.Comment: 8 pages, 11 figure
Cooling in the single-photon strong-coupling regime of cavity optomechanics
In this paper we discuss how red-sideband cooling is modified in the
single-photon strong-coupling regime of cavity optomechanics where the
radiation pressure of a single photon displaces the mechanical oscillator by
more than its zero-point uncertainty. Using Fermi's Golden rule we calculate
the transition rates induced by the optical drive without linearizing the
optomechanical interaction. In the resolved-sideband limit we find
multiple-phonon cooling resonances for strong single-photon coupling that lead
to non-thermal steady states including the possibility of phonon anti-bunching.
Our study generalizes the standard linear cooling theory.Comment: 4 pages, 3 figure
The subdiffusive target problem: Survival probability
The asymptotic survival probability of a spherical target in the presence of
a single subdiffusive trap or surrounded by a sea of subdiffusive traps in a
continuous Euclidean medium is calculated. In one and two dimensions the
survival probability of the target in the presence of a single trap decays to
zero as a power law and as a power law with logarithmic correction,
respectively. The target is thus reached with certainty, but it takes the trap
an infinite time on average to do so. In three dimensions a single trap may
never reach the target and so the survival probability is finite and, in fact,
does not depend on whether the traps move diffusively or subdiffusively. When
the target is surrounded by a sea of traps, on the other hand, its survival
probability decays as a stretched exponential in all dimensions (with a
logarithmic correction in the exponent for ). A trap will therefore reach
the target with certainty, and will do so in a finite time. These results may
be directly related to enzyme binding kinetics on DNA in the crowded cellular
environment.Comment: 6 pages. References added, improved account of previous results and
typos correcte
Birefringent Gravitational Waves and the Consistency Check of Inflation
In this work we show that the gravitational Chern-Simons term, aside from
being a key ingredient in inflationary baryogenesis, modifies super-horizon
gravitational waves produced during inflation. We compute the super-Hubble
gravitational power spectrum in the slow-roll approximation and show that its
overall amplitude is modified while its spectral index remains unchanged (at
leading order in the slow-roll parameters). Then, we calculate the correction
to the tensor to scalar ratio, T/S. We find a correction of T/S which is
dependent on (more precisely quadratic in ), the parameter
characterizing the amplitude of the Chern-Simons terms. In a stringy embedding
of the leptogenesis mechanism, is the ratio between the Planck scale
and the fundamental string scale. Thus, in principle, we provide a direct probe
of leptogenesis due to stringy dynamics in the Cosmic Microwave Background
(CMB). However, we demonstrate that the corresponding correction of T/S is in
fact very small and not observable in the regime where our calculations are
valid. To obtain a sizable effect, we argue that a non-linear calculation is
necessary.Comment: 9 pages, 1 figure, RevTe
Unified Treatment of Mixed Vector-Scalar Screened Coulomb Potentials for Fermions
The problem of a fermion subject to a general mixing of vector and scalar
screened Coulomb potentials in a two-dimensional world is analyzed and
quantization conditions are found.Comment: 7 page
Position and Momentum Uncertainties of the Normal and Inverted Harmonic Oscillators under the Minimal Length Uncertainty Relation
We analyze the position and momentum uncertainties of the energy eigenstates
of the harmonic oscillator in the context of a deformed quantum mechanics,
namely, that in which the commutator between the position and momentum
operators is given by [x,p]=i\hbar(1+\beta p^2). This deformed commutation
relation leads to the minimal length uncertainty relation \Delta x >
(\hbar/2)(1/\Delta p +\beta\Delta p), which implies that \Delta x ~ 1/\Delta p
at small \Delta p while \Delta x ~ \Delta p at large \Delta p. We find that the
uncertainties of the energy eigenstates of the normal harmonic oscillator
(m>0), derived in Ref. [1], only populate the \Delta x ~ 1/\Delta p branch. The
other branch, \Delta x ~ \Delta p, is found to be populated by the energy
eigenstates of the `inverted' harmonic oscillator (m<0). The Hilbert space in
the 'inverted' case admits an infinite ladder of positive energy eigenstates
provided that \Delta x_{min} = \hbar\sqrt{\beta} > \sqrt{2}
[\hbar^2/k|m|]^{1/4}. Correspondence with the classical limit is also
discussed.Comment: 16 pages, 31 eps figure
The Big Bang and Inflation United by an Analytic Solution
Exact analytic solutions for a class of scalar-tensor gravity theories with a
hyperbolic scalar potential are presented. Using an exact solution we have
successfully constructed a model of inflation that produces the spectral index,
the running of the spectral index and the amplitude of scalar perturbations
within the constraints given by the WMAP 7 years data. The model simultaneously
describes the Big Bang and inflation connected by a specific time delay between
them so that these two events are regarded as dependent on each other. In
solving the Fridemann equations, we have utilized an essential Weyl symmetry of
our theory in 3+1 dimensions which is a predicted remaining symmetry of
2T-physics field theory in 4+2 dimensions. This led to a new method of
obtaining analytic solutions in 1T field theory which could in principle be
used to solve more complicated theories with more scalar fields. Some
additional distinguishing properties of the solution includes the fact that
there are early periods of time when the slow roll approximation is not valid.
Furthermore, the inflaton does not decrease monotonically with time, rather it
oscillates around the potential minimum while settling down, unlike the slow
roll approximation. While the model we used for illustration purposes is
realistic in most respects, it lacks a mechanism for stopping inflation. The
technique of obtaining analytic solutions opens a new window for studying
inflation, and other applications, more precisely than using approximations.Comment: V2 improve computation with better agreement with WMAP 7 years data,
and also point out an exact solution for cyclic cosmolog
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