14,432 research outputs found
Fourth Amendment Accommodations: (UN)Compelling Public Needs, Balancing Acts, and the Fiction of Consent
The problems of public housing-including crime, drugs, and gun violence- have received an enormous amount of national attention. Much attention has also focused on warrantless searches and consent searches as solutions to these problems. This Note addresses the constitutionality of these proposals and asserts that if the Supreme Court\u27s current Fourth Amendment jurisprudence is taken to its logical extremes, warrantless searches in public housing can be found constitutional. The author argues, however, that such an interpretation fails to strike the proper balance between public need and privacy in the public housing context. The Note concludes by proposing alternative consent-based regimes that would pass constitutional muster
Bose-Einstein condensation of magnons in magnets with predominant ferromagnetic interaction
We discuss Bose-Einstein condensation of magnons (BEC) in magnets with
predominant ferromagnetic (FM) interaction in magnetic field near
saturation (). Because is independent of FM couplings, magnetic
materials of this type can have small that makes them promising
candidates for experimental investigation of BEC. Ferromagnets with easy-plane
anisotropy and antiferromagnets (AFs) containing weakly coupled FM planes or
chains are discussed in detail. We observe small effective interaction between
magnons near the QCP in such magnets, in contrast to AFs with strong AF
coupling previously discussed. In particular, this smallness allows us to find
crossovers in the critical temperature from
to in quasi-1D magnets, and from to
() in quasi-2D ones.Comment: 9 pages, 4 figure. The paper has been rewritten considerably. In
particular, discussion of crossovers in the critical temperature in
quasi-low-dimensional magnets is adde
Correlation functions of a Lieb-Liniger Bose gas
The ground-state correlation functions of a one-dimensional homogeneous Bose
system described by the Lieb-Liniger Hamiltonian are investigated by using
exact quantum Monte Carlo techniques. This article is an extension of a
previous study published in Phys. Rev. A {\bf 68}, 031602 (2003). New results
on the local three-body correlator as a function of the interaction strength
are included and compared with the measured value from three-body loss
experiments. We also carry out a thorough study of the short- and long-range
behavior of the one-body density matrix.Comment: 10 pages, 8 figures, contribution to Cortona BEC JPB special issu
Two-species fermion mixtures with population imbalance
We analyze the phase diagram of uniform superfluidity for two-species fermion
mixtures from the Bardeen-Cooper-Schrieffer (BCS) to Bose-Einstein condensation
(BEC) limit as a function of the scattering parameter and population imbalance.
We find at zero temperature that the phase diagram of population imbalance
versus scattering parameter is asymmetric for unequal masses, having a larger
stability region for uniform superfluidity when the lighter fermions are in
excess. In addition, we find topological quantum phase transitions associated
with the disappearance or appearance of momentum space regions of zero
quasiparticle energies. Lastly, near the critical temperature, we derive the
Ginzburg-Landau equation, and show that it describes a dilute mixture of
composite bosons and unpaired fermions in the BEC limit.Comment: 4 pages with 3 figures, accepted version to PR
On O-X mode conversion in 2D inhomogeneous plasma with a sheared magnetic field
The conversion of an ordinary wave to an extraordinary wave in a 2D
inhomogeneous slab model of the plasma confined by a sheared magnetic field is
studied analytically.Comment: sub. to PPC
The Zel'dovich effect and evolution of atomic Rydberg spectra along the Periodic Table
In 1959 Ya. B. Zel'dovich predicted that the bound-state spectrum of the
non-relativistic Coulomb problem distorted at small distances by a short-range
potential undergoes a peculiar reconstruction whenever this potential alone
supports a low-energy scattering resonance. However documented experimental
evidence of this effect has been lacking. Previous theoretical studies of this
phenomenon were confined to the regime where the range of the short-ranged
potential is much smaller than Bohr's radius of the Coulomb field. We go beyond
this limitation by restricting ourselves to highly-excited s states. This
allows us to demonstrate that along the Periodic Table of elements the
Zel'dovich effect manifests itself as systematic periodic variation of the
Rydberg spectra with a period proportional to the cubic root of the atomic
number. This dependence, which is supported by analysis of experimental and
numerical data, has its origin in the binding properties of the ionic core of
the atom.Comment: 17 pages, 12 figure
Effects of Sequence Disorder on DNA Looping and Cyclization
Effects of sequence disorder on looping and cyclization of the
double-stranded DNA are studied theoretically. Both random intrinsic curvature
and inhomogeneous bending rigidity are found to result in a remarkably wide
distribution of cyclization probabilities. For short DNA segments, the range of
the distribution reaches several orders of magnitude for even completely random
sequences. The ensemble averaged values of the cyclization probability are also
calculated, and the connection to the recent experiments is discussed.Comment: 8 pages, 4 figures, LaTeX; accepted to Physical Review E; v2: a
substantially revised version; v3: references added, conclusions expanded,
minor editorial corrections to the text; v4: a substantially revised and
expanded version (total number of pages doubled); v5: new Figure 4, captions
expanded, minor editorial improvements to the tex
KKbar molecules with momentum-dependent interactions
It is shown that the momentum-dependent kaon-antikaon interactions generated
via vector meson exchange from the standard SU_V(3) x SU_A(3) interaction
Lagrangian lead to a non-local potential in coordinate space that can be
incorporated without approximation into a non-relativistic version of the
Bethe-Salpeter wave equation containing a radial-dependent effective kaon mass
appearing in a fully symmetrized kinetic energy operator, in addition to a
local potential. Estimates of the mass and decay widths of f_0(980) and
a_0(980), considered as KKbar molecules of isospin 0 and 1, as well as for
K^+K^- atomic bound states (kaonium) are presented, and compared with previous
studies of a similar nature. It is argued that without a better knowledge of
hadronic form factors it is not possible to distinguish between the molecular
versus elementary particle models for the structure of the light scalar mesons.Comment: 14 pages, 2 tables, 5 figures. Added subsection on s-channel
exchange, additional remarks on the possible effect of gluon exchange, and 1
additional figur
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