23,929 research outputs found
Fractional exclusion and braid statistics in one dimension: a study via dimensional reduction of Chern-Simons theory
The relation between braid and exclusion statistics is examined in
one-dimensional systems, within the framework of Chern-Simons statistical
transmutation in gauge invariant form with an appropriate dimensional
reduction. If the matter action is anomalous, as for chiral fermions, a
relation between braid and exclusion statistics can be established explicitly
for both mutual and nonmutual cases. However, if it is not anomalous, the
exclusion statistics of emergent low energy excitations is not necessarily
connected to the braid statistics of the physical charged fields of the system.
Finally, we also discuss the bosonization of one-dimensional anyonic systems
through T-duality.Comment: 19 pages, fix typo
Broken symmetry, excitons, gapless modes and topological excitations in Trilayer Quantum Hall systems
We study the interlayer coherent incompressible phase in Trilayer Quantum
Hall systems (TLQH) at total filling factor from three
approaches:
Mutual Composite Fermion (MCF), Composite Boson (CB) and wavefunction
approach.
Just like in Bilayer Quantum Hall system, CB approach is superior than
MCF approach in studying TLQH with broken symmetry. The Hall and Hall drag
resistivities are found to be quantized at . Two neutral gapless
modes with linear dispersion relations are identified and the ratio of the two
velocities is close to .
The novel excitation spectra are classified into two classes: Charge neutral
bosonic
2-body bound states and Charge fermionic 3-body bound states.
In general, there are two 2-body Kosterlize-Thouless (KT) transition
temperatures and one 3-body KT transition. The Charge 3-body
fermionic bound states may be the main dissipation source of transport
measurements.
The broken symmetry in terms of algebra is studied. The structure
of excitons and their flowing patterns are given. The coupling between the two
Goldstone modes may lead to the broadening in the zero-bias peak in the
interlayer correlated tunnelings of the TLQH. Several interesting features
unique to TLQH are outlined.
Limitations of the CB approach are also pointed out.Comment: 10 pages, 3 figures, Final version to be published in Phys. Rev.
Structural phase transition and dielectric relaxation in Pb(Zn1/3Nb2/3)O3 single crystals
The structure and the dielectric properties of Pb(Zn1/3Nb2/3)O3 (PZN) crystal
have been investigated by means of high-resolution synchrotron x-ray
diffraction (with an x-ray energy of 32 keV) and dielectric spectroscopy (in
the frequency range of 100 Hz - 1 MHz). At high temperatures, the PZN crystal
exhibits a cubic symmetry and polar nanoregions inherent to relaxor
ferroelectrics are present, as evidenced by the single (222) Bragg peak and by
the noticeable tails at the basis of the peak. At low temperatures, in addition
to the well-known rhombohedral phase, another low-symmetry, probably
ferroelectric, phase is found. The two phases coexist in the form of mesoscopic
domains. The para- to ferroelectric phase transition is diffused and observed
between 325 and 390 K, where the concentration of the low-temperature phases
gradually increases and the cubic phase disappears upon cooling. However, no
dielectric anomalies can be detected in the temperature range of diffuse phase
transition. The temperature dependence of the dielectric constant show the
maximum at higher temperature (Tm = 417 - 429 K, depending on frequency) with
the typical relaxor dispersion at T < Tm and the frequency dependence of Tm
fitted to the Vogel-Fulcher relation. Application of an electric field upon
cooling from the cubic phase or poling the crystal in the ferroelectric phase
gives rise to a sharp anomaly of the dielectric constant at T 390 K and
diminishes greatly the dispersion at lower temperatures, but the dielectric
relaxation process around Tm remains qualitatively unchanged. The results are
discussed in the framework of the present models of relaxors and in comparison
with the prototypical relaxor ferroelectric Pb(Mg1/3Nb2/3)O3.Comment: PDF file, 13 pages, 6 figures collected on pp.12-1
Monoclinic phase in the relaxor-based piezo-/ ferroelectric Pb(MgNb-PbTiO system
A ferroelectric monoclinic phase of space group ( type) has been
discovered in 0.65Pb(MgNb-0.35PbTiO by means of high
resolution synchrotron X-ray diffraction. It appears at room temperature in a
single crystal previously poled under an electric field of 43 kV/cm applied
along the pseudocubic [001] direction, in the region of the phase diagram
around the morphotropic phase boundary between the rhombohedral (R3m) and the
tetragonal (P4mm) phases. The monoclinic phase has lattice parameters a = 5.692
A, b = 5.679 A, c = 4.050 A and = , with the b-axis
oriented along the pseudo-cubic [110] direction . It is similar to the
monoclinic phase observed in PbZrTiO, but different from that
recently found in Pb(ZnNb-PbTiO, which is of space
group ( type).Comment: Revised version after referees' comments. PDF file. 6 pages, 4
figures embedde
Momentum Distribution of Near-Zero-Energy Photoelectrons in the Strong-Field Tunneling Ionization in the Long Wavelength Limit
We investigate the ionization dynamics of Argon atoms irradiated by an
ultrashort intense laser of a wavelength up to 3100 nm, addressing the momentum
distribution of the photoelectrons with near-zero-energy. We find a surprising
accumulation in the momentum distribution corresponding to meV energy and a
\textquotedblleft V"-like structure at the slightly larger transverse momenta.
Semiclassical simulations indicate the crucial role of the Coulomb attraction
between the escaping electron and the remaining ion at extremely large
distance. Tracing back classical trajectories, we find the tunneling electrons
born in a certain window of the field phase and transverse velocity are
responsible for the striking accumulation. Our theoretical results are
consistent with recent meV-resolved high-precision measurements.Comment: 5 pages, 4 figure
The dual parameterization of the proton generalized parton distribution functions H and E and description of the DVCS cross sections and asymmetries
We develop the minimal model of a new leading order parameterization of GPDs
introduced by Shuvaev and Polyakov. The model for GPDs H and E is formulated in
terms of the forward quark distributions, the Gegenbauer moments of the D-term
and the forward limit of the GPD E. The model is designed primarely for small
and medium-size values of x_B, x_B \leq 0.2.
We examined two different models of the t-dependence of the GPDs: The
factorized exponential model and the non-factorized Regge-motivated model.
Using our model, we successfully described the DVCS cross section measured by
H1 and ZEUS, the moments of the beam-spin A_{LU}^{\sin \phi}, beam-charge
A_{C}^{\cos \phi} and transversely-polarized target A_{UT}^{\sin \phi \cos
\phi} DVCS asymmetries measured by HERMES and A_{LU}^{\sin \phi} measured by
CLAS. The data on A_{C}^{\cos \phi} prefers the Regge-motivated model of the
t-dependence of the GPDs. The data on A_{UT}^{\sin \phi \cos \phi} indicates
that the u and d quarks carry only a small fraction of the proton total angular
momentum.Comment: 33 pages, 11 figure
On the relationship between dynamic solubility, multi-atom bubble nucleation, irradiationinduced re-solution, and the bubble size distribution in Xe implanted Mo
U-Mo alloys are candidate fuels for both research and test reactors, as well as for advanced power reactors. A critical requirement for these candidate fuels is stable swelling behavior over their expected lifetime. In-reactor deformation of these materials is primarily driven by irradiation induced swelling where the primary component is fission gas (Xe and Kr) generated by decay of the primary fission products
- …