5,844 research outputs found
Anomalous Resonance of the Symmetric Single-Impurity Anderson Model in the Presence of Pairing Fluctuations
We consider the symmetric single-impurity Anderson model in the presence of
pairing fluctuations. In the isotropic limit, the degrees of freedom of the
local impurity are separated into hybridizing and non-hybridizing modes. The
self-energy for the hybridizing modes can be obtained exactly, leading to two
subbands centered at . For the non-hybridizing modes, the second order
perturbation yields a singular resonance of the marginal Fermi liquid form. By
multiplicative renomalization, the self-energy is derived exactly, showing the
resonance is pinned at the Fermi level, while its strength is weakened by
renormalization.Comment: 4 pages, revtex, no figures. To be published in Physical Review
Letter
Heavy-Fermions in a Transition-Metal Compound:
The recent discovery of heavy-Fermion properties in Lithium Vanadate and the
enormous difference in its properties from the properties of Lithium Titanate
as well as of the manganite compounds raise some puzzling questions about
strongly correlated Fermions. These are disscussed as well as a solution to the
puzzles provided.Comment: late
Swimming statistics of cargo-loaded single bacteria
Burgeoning interest in the area of bacteria-powered micro robotic systems
prompted us to study the dynamics of cargo transport by single bacteria. In
this paper, we have studied the swimming behaviour of oil-droplets attached as
a cargo to the cell bodies of single bacteria. The oil-droplet loaded bacteria
exhibit super-diffusive motion which is characterized by high degree of
directional persistence. Interestingly, bacteria could navigate even when
loaded with oil-droplets as large as 8 microns with an effective increase in
rotational drag by more than 2 orders when compared to free bacteria. Further,
the directional persistence of oil-droplet loaded bacteria was independent of
the cargo size
Evaluation of gas phase mass transfer at low reynolds numbers: a new model system
A new experimental system is presented which is suitable for studying gas side mass transfer coefficients in packed columns at Reynolds numbers even lower than 1.0. The system involves desorption of iodine from aqueous KI solutions. The reversible complex formation between iodine and iodine ions effectively slows down the concentration changes which otherwise would be too rapid for accurate experimentation
Low-Frequency Quantum Oscillations due to Strong Electron Correlations
The normal-state energy spectrum of the two-dimensional - model in a
homogeneous perpendicular magnetic field is investigated. The density of states
at the Fermi level as a function of the inverse magnetic field
reveals oscillations in the range of hole concentrations . The
oscillations have both high- and low-frequency components. The former
components are connected with large Fermi surfaces, while the latter with van
Hove singularities in the Landau subbands, which traverse the Fermi level with
changing . The singularities are related to bending the Landau subbands due
to strong electron correlations. Frequencies of these components are of the
same order of magnitude as quantum oscillation frequencies observed in
underdoped cuprates.Comment: 10 pages, 3 figures, Proc. NSS-2013, Yalta. arXiv admin note: text
overlap with arXiv:1308.056
Power Allocation for Uniform Illumination with Stochastic LED Arrays
Light has traditionally been used for making objects visibl
e to the naked eye. Lately,
there has been tremendous interest in using it for free space
communication [1]. This has
simultaneously been accompanied by significant interest in
light emitting diodes (LEDs)
that have been replacing conventional light sources in almo
st all applications [2–4]. Fair
amount of existing literature has focused on achieving unif
orm irradiance over a planar
surface [5–8], beginning with the problem of finding the opti
mal LED geometry at the
light source to achieve uniform irradiance [9]. This was don
e by using the irradiance
distributions at the closest points on the incident surface
. The case of LEDs using a
freeform lens with a large view angle has been considered in [
10]. More literature on
similar themes is available in [11,12]
New excitations in bcc He - an inelastic neutron scattering study
We report neutron scattering measurements on bcc solid % He. We studied
the phonon branches and the recently discovered ''optic-like'' branch along the
main crystalline directions. In addition, we discovered another, dispersionless
"optic-like'' branch at an energy around 1 meV (~11K). The properties of
the two "optic-like" branches seem different. Since one expects only 3 acoustic
phonon branches in a monoatomic cubic crystal, these new branches must
represent different type of excitations. One possible interpretation involves
localized excitations unique to a quantum solid.Comment: 4 pages, 3 figures, accepted by PRB, Rapid Communication
Metals in high magnetic field: a new universality class of Fermi liquids
Parquet equations, describing the competition between superconducting and
density-wave instabilities, are solved for a three-dimensional isotropic metal
in a high magnetic field when only the lowest Landau level is filled. In the
case of a repulsive interaction between electrons, a phase transition to the
density-wave state is found at finite temperature. In the opposite case of
attractive interaction, no phase transition is found. With decreasing
temperature , the effective vertex of interaction between electrons
renormalizes toward a one-dimensional limit in a self-similar way with the
characteristic length (transverse to the magnetic field) decreasing as
( is a cutoff). Correlation functions have
new forms, previously unknown for conventional one-dimensional or
three-dimensional Fermi-liquids.Comment: 13 pages + 4 figures (included
- …