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Lateral shearing interferometry for high-NA EUV wavefront metrology
We present a lateral shearing interferometer suitable for high-NA EUV wavefront metrology. In this interferometer, a geometric model is used to accurately characterize and predict systematic errors that come from performing interferometry at high NA. This interferometer is compatible with various optical geometries, including systems where the image plane is tilted with respect to the optical axis, as in the Berkeley MET5. Simulation results show that the systematic errors in tilted geometries can be reduced by aligning the shearing interferometer grating and detector parallel to the image plane. Subsequent residual errors can be removed by linear fitting
Quantum interference in nested d-wave superconductors: a real-space perspective
We study the local density of states around potential scatterers in d-wave
superconductors, and show that quantum interference between impurity states is
not negligible for experimentally relevant impurity concentrations. The two
impurity model is used as a paradigm to understand these effects analytically
and in interpreting numerical solutions of the Bogoliubov-de Gennes equations
on fully disordered systems. We focus primarily on the globally particle-hole
symmetric model which has been the subject of considerable controversy, and
give evidence that a zero-energy delta function exists in the DOS. The
anomalous spectral weight at zero energy is seen to arise from resonant
impurity states belonging to a particular sublattice, exactly as in the
2-impurity version of this model. We discuss the implications of these findings
for realistic models of the cuprates.Comment: 12 pages, 10 figs, submitted to Phys. Rev.
Two impurities in a d-wave superconductor:local density of states
We study the problem of two local potential scatterers in a d-wave
superconductor, and show how quasiparticle bound state wave functions
interfere. Each single-impurity electron and hole resonance energy is in
general split in the presence of a second impurity into two, corresponding to
one even parity and one odd parity state. We calculate the local density of
states (LDOS), and argue that scanning tunneling microscopy (STM) measurements
should be capable of extracting information about the Green's function in the
pure system by a systematic study of 2-impurity configurations. In some
configurations highly localized, long-lived states are predicted. We discuss
the effects of realistic band structures, and how 2-impurity STM measurements
could help distinguish between current explanations of LDOS impurity spectra in
the BSCCO-2212 system.Comment: 16 pages,21 figure,New Version to be Published on P.R.
Coarse-Grained Picture for Controlling Complex Quantum Systems
We propose a coarse-grained picture to control ``complex'' quantum dynamics,
i.e., multi-level-multi-level transition with a random interaction. Assuming
that optimally controlled dynamics can be described as a Rabi-like oscillation
between an initial and final state, we derive an analytic optimal field as a
solution to optimal control theory. For random matrix systems, we numerically
confirm that the analytic optimal field steers an initial state to a target
state which both contains many eigenstates.Comment: jpsj2.cls, 2 pages, 3 figure files; appear in J. Phys. Soc. Jpn.
Vol.73, No.11 (Nov. 15, 2004
Numerical simulations of negative-index refraction in wedge-shaped metamaterials
A wedge-shaped structure made of split-ring resonators (SRR) and wires is
numerically simulated to evaluate its refraction behavior. Four frequency
bands, namely, the stop band, left-handed band, ultralow-index band, and
positive-index band, are distinguished according to the refracted field
distributions. Negative phase velocity inside the wedge is demonstrated in the
left-handed band and the Snell's law is conformed in terms of its refraction
behaviors in different frequency bands. Our results confirmed that negative
index of refraction indeed exists in such a composite metamaterial and also
provided a convincing support to the results of previous Snell's law
experiments.Comment: 18 pages, 6 figure
Electromagnetic decays of vector mesons as derived from QCD sum rules
We apply the method of QCD sum rules in the presence of external
electromagnetic fields to the problem of the electromagnetic
decays of various vector mesons, such as , and . The induced condensates obtained previously
from the study of baryon magnetic moments are adopted, thereby ensuring the
parameter-free nature of the present calculation. Further consistency is
reinforced by invoking various QCD sum rules for the meson masses. The
numerical results on the various radiative decays agree very well with the
experimental data.Comment: To appear in Phys. Lett.
Magnetic Moments of Pentaquarks
If the of and pentaquarks is really found to
be by future experiments, they will be accompanied by
partners in some models. It is reasonable to expect that
these states will also be discovered in the near future with
the current intensive experimental and theoretical efforts. We estimate
pentaquark magnetic moments using different models.Comment: 13 page
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