175 research outputs found
Time-reversed two-photon interferometry for phase super-resolution
We observed two-photon phase super-resolution in an unbalanced Michelson
interferometer with classical Gaussian laser pulses. Our work is a
time-reversed version of a two-photon interference experiment using an
unbalanced Michelson interferometer. A measured interferogram exhibits
two-photon phase super-resolution with a high visibility of 97.9% \pm 0.4%. Its
coherence length is about 22 times longer than that of the input laser pulses.
It is a classical analogue to the large difference between the one- and
two-photon coherence lengths of entangled photon pairs.Comment: 6 pages, 4 figure
Observation of nonlinear variations in three-vertex geometric phase in two-photon polarization qutrit
We experimentally observed nonlinear variations in the three-vertex geometric
phase in a two- photon polarization qutrit. The three-vertex geometric phase is
defined by three quantum states, which generally forms a three-state (qutrit)
system. By changing one of the three constituent states, we observed two rapid
increases in the three-vertex geometric phase. The observed variations are
inherent in a three-state system and cannot be observed in a two-state system.
We used a time-reversed two-photon interferometer to measure the geometric
phase with much more intense signals than those of a typical two-photon
interferometer.Comment: 6 pages, 5 figure
Bloch sphere representation of three-vertex geometric phases
The properties of the geometric phases between three quantum states are
investigated in a high-dimensional Hilbert space using the Majorana
representation of symmetric quantum states. We found that the geometric phases
between the three quantum states in an N-state quantum system can be
represented by N-1 spherical triangles on the Bloch sphere. The parameter
dependence of the geometric phase was analyzed based on this picture. We found
that the geometric phase exhibits rich nonlinear behavior in a high-dimensional
Hilbert space.Comment: 5 pages, 4 figure
Effect of day-to-day variations in adrenal cortex hormone levels on abdominal symptoms
<p>Abstract</p> <p>Introduction</p> <p>The hypothalamic-pituitary-adrenal axis is known to be related to abdominal symptoms, and the relationship between abdominal pain and cortisol secretory patterns has been previously investigated using a cross-sectional approach. Here, we investigated the effect of day-to-day variations in salivary cortisol and dehydroepiandrosterone-sulfate levels on abdominal symptoms in healthy individuals.</p> <p>Methods</p> <p>Eleven college students (4 males and 7 females) participated in this study. The participants were asked to collect their saliva immediately after awakening and before bedtime for eight consecutive days. They also completed a questionnaire about abdominal symptoms before bedtime. The linear mixed model was applied to analyze the effects of the day-by-day variability or the 8-day average adrenal hormone level (at awakening, before bedtime, slope from awakening to bedtime) on abdominal symptoms.</p> <p>Results</p> <p>The day-to-day variability of cortisol levels before bedtime was negatively related with loose stool, while the day-to-day variability of the cortisol slope was positively correlated with loose stool. A low 8-day average dehydroepiandrosterone-sulfate level at awakening was positively related with frequent bowel movements, loose stool, and long bouts of severe abdominal pain. Likewise, a low 8-day average dehydroepiandrosterone-sulfate slope was positively related with long bouts of abdominal pain.</p> <p>Conclusions</p> <p>Low cortisol levels before bedtime and a steeper diurnal cortisol slope during the day may be related to bouts of diarrhea during the day.</p
- …