5,076 research outputs found
Single-color two-photon spectroscopy of Rydberg states in electric fields
Rydberg states of atomic helium with principal quantum numbers ranging from
n=20 to n=100 have been prepared by non-resonance-enhanced single-color
two-photon excitation from the metastable 2 {^3}S{_1} state. Photoexcitation
was carried out using linearly and circularly polarized pulsed laser radiation.
In the case of excitation with circularly polarized radiation, Rydberg states
with azimuthal quantum number |m_{\ell}|=2 were prepared in zero electric
field, and in homogeneous electric fields oriented parallel to the propagation
axis of the laser radiation. In sufficiently strong electric fields, individual
Rydberg-Stark states were resolved spectroscopically, highlighting the
suitability of non-resonance-enhanced multiphoton excitation schemes for the
preparation of long-lived high-|m_{\ell}| hydrogenic Rydberg states for
deceleration and trapping experiments. Applications of similar schemes for
Doppler-free excitation of positronium atoms to Rydberg states are also
discussed
Home Appreciation Participation Notes: A Solution to Housing Affordability and the Current Mortgage Crisis
This paper introduces Home Appreciation Participation Notes (HAPNs), an innovative new housing finance tool. Housing is a commodity providing two distinct utilities: shelter and investment. Traditionally, buyers have had to purchase both elements in tandom. HAPNs allow buyers to purchase these elements individually. Thus, buyers can focus on purchasing housing units that best fit their shelter needs, investing in housing appreciation to whatever extent is appropriate for the needs of their investment portfolio. HAPNs are different from previous financing tools in three key ways: there is no payment burden until ownership of the home is transferred, the risk of housing price declines is shifted to investors, and the final payoff is indexed to the appreciation rates of local housing prices. With these three features, HAPNs considerably improve the affordability of homeownership while reducing the risk of default and avoiding the moral hazard associated with shared appreciation instruments.
Investigating garment drape behaviour
Drapeability is one of the most important visual properties affecting garment appearance. Even though there are many studies concerned with fabric drape, understanding about the drape behaviour of garments is very limited. This study analyzes the key properties affecting the drape behaviour of garments to provide prediction equations. Results are statistically analyzed. From multiple regression analysis, drape rank scores obtained from subjective analyses are predicted using weight, bending modulus and extensibility measured at 100 gf/cm with a correlation coefficient of 0.94. Ranking values obtained from subjective analyses can be more easily predicted using both circularity and wave length minimum. A new equation was derived to predict drape rank score values of garments (correlation coefficient r = 0.97) depending on circularity and wavelength minimum
Quark-Novae Ia in the Hubble diagram: Implications For Dark Energy
The accelerated expansion of the Universe was proposed through the use of
Type-Ia SNe as standard candles. The standardization depends on an empirical
correlation between the stretch/color and peak luminosity of the light curves.
The use of Type Ia SN as standard candles rests on the assumption that their
properties (and this correlation) do not vary with red-shift. We consider the
possibility that the majority of Type-Ia SNe are in fact caused by a Quark-Nova
detonation in a tight neutron-star-CO-white-dwarf binary system; a Quark-Nova
Ia. The spin-down energy injected by the Quark Nova remnant (the quark star)
contributes to the post-peak light curve and neatly explains the observed
correlation between peak luminosity and light curve shape. We demonstrate that
the parameters describing Quark-Novae Ia are NOT constant in red-shift.
Simulated Quark-Nova Ia light curves provide a test of the stretch/color
correlation by comparing the true distance modulus with that determined using
SN light curve fitters. We determine a correction between the true and fitted
distance moduli which when applied to Type-Ia SNe in the Hubble diagram
recovers the Omega_M = 1 cosmology. We conclude that Type-Ia SNe observations
do not necessitate the need for an accelerating expansion of the Universe (if
the observed SNe-Ia are dominated by QNe-Ia) and by association the need for
Dark Energy.Comment: 22 pages, 6 figures. Accepted for publication in Research in
Astronomy and Astrophysic
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