13,957 research outputs found
Intensity-Dependent Enhancement of Saturable Absorption in PbS-Au4 Nanohybrid Composites: Evidence for Resonant Energy Transfer by Auger Recombination
Intensity-dependent enhancement of saturable absorption in a film of PbS-Au4
nanohybrid composites has been observed by femtosecond time-resolved transient
absorption measurement at 780 nm. The nonlinear absorption coefficient of
saturable absorption in PbS-Au4 nanohybrid composites is found to be dependent
on excitation irradiance and it is determined to be -2.9 cm/GW at 78 GW/cm2, an
enhancement of nearly fourfold in comparison with that of pure PbS quantum dots
(QDs). The enhancement is attributed to excitation of surface plasmon by
resonant energy transfer between PbS QDs and Au nanoparticles through Auger
recombination.Comment: 14 pages, 3 figures. Accepted in Appl. Phys. Lett. (2008
Standard Model of Particle Physics Violating Crypto-Nonlocal Realism
It has been well established that quantum mechanics (QM) violates Bell
inequalities (BI), which are consequences of local realism (LR). Remarkably QM
also violates Leggett inequalities (LI), which are consequences of a class of
nonlocal realism called crypto-nonlocal realism (CNR). Both LR and CNR assume
that measurement outcomes are determined by preexisting objective properties,
as well as hidden variables (HV) not considered in QM. We extend CNR and LI to
include the case that the measurement settings are not externally fixed, but
determined by hidden variables (HV). We derive a new version of LI, which is
then shown to be violated by entangled mesons, if
charge-conjugation-parity (CP) symmetry is indirectly violated, as indeed
established. The experimental result is quantitatively estimated by using the
indirect CP violation parameter, and the maximum of a suitably defined relative
violation is about . Our work implies that standard model (SM) of
particle physics violates CNR. Our LI can also be tested in other systems such
as photon polarizations.Comment: 28 page
Entangled baryons: violation of Inequalities based on local realism assuming dependence of decays on hidden variables
Bell inequalities are consequences of local realism while violated by quantum
mechanics. In particle physics, entangled high energy particles can be produced
from a common source, and the decay of each particle plays the role of
measurement. However, in a hidden variable theory, the decay could be
determined by hidden variables. This loophole killed such approaches to Bell
test in particle physics. It is a special form of measurement-setting or
free-will loophole, which also exists in other systems. Using entangled
baryons, we present new inequalities of local realism with the explicit
assumption of the dependence of the decays on hidden variables, as well as the
consideration of the statistical mixture of polarizations and the separation of
local hidden variables for objects with spacelike distances. These violations
closes the measurement-setting loophole once and for all. We propose to use the
processes and to test our inequalities, and show that their violations are
likely to be observed with the data already collected in BESIII.Comment: 11 page
Exact conditions for antiUnruh effect in (1+1)-dimensional spacetime
Exact conditions for antiUnruh effect in (1+1)-dimensional spacetime are
obtained. For detectors with Gaussian switching functions, the analytic results
are similar to previous ones, indicating that antiUnruh effect occurs when the
energy gap matches the characteristic time scale. However, this conclusion does
not hold for detectors with square wave switching functions, in which case the
condition turns out to depend on both the energy gap and the characteristic
time scale in some nontrivial way. We also show analytically that there is no
antiUnruh effect for detectors with Gaussian switching functions in
(3+1)-dimensional spacetime.Comment: 16 page
- …