28 research outputs found
Self-gravitating stellar collapse: explicit geodesics and path integration
We extend the work of Oppenheimer & Synder to model the gravitational
collapse of a star to a black hole by including quantum mechanical effects. We
first derive closed-form solutions for classical paths followed by a particle
on the surface of the collapsing star in Schwarzschild and Kruskal coordinates
for space-like, time-like and light-like geodesics. We next present an
application of these paths to model the collapse of ultra-light dark matter
particles, which necessitates incorporating quantum effects. To do so we treat
a particle on the surface of the star as a wavepacket and integrate over all
possible paths taken by the particle. The waveform is computed in Schwarzschild
coordinates and found to exhibit an ingoing and an outgoing component, where
the former contains the probability of collapse, while the latter contains the
probability that the star will disperse. These calculations pave the way for
investigating the possibility of quantum collapse that does not lead to black
hole formation as well as for exploring the nature of the wavefunction inside
r=2M.Comment: 13 pages, 6 figure
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies,
expounded a compelling and poetic vision for the future of astronomy, calling
for an infrared-optimized space telescope with an aperture of at least .
With the support of their governments in the US, Europe, and Canada, 20,000
people realized that vision as the James Webb Space Telescope. A
generation of astronomers will celebrate their accomplishments for the life of
the mission, potentially as long as 20 years, and beyond. This report and the
scientific discoveries that follow are extended thank-you notes to the 20,000
team members. The telescope is working perfectly, with much better image
quality than expected. In this and accompanying papers, we give a brief
history, describe the observatory, outline its objectives and current observing
program, and discuss the inventions and people who made it possible. We cite
detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space
Telescope Overview, 29 pages, 4 figure
Validation Set
Validation Set is a work of hard science fiction, containing 14 original short stories held together by a 15th, original, frame story which can be read as a stand-alone short story or with the other thirteen stories interleaved in order. Validation Set deals with the theme of grief through the lens of how near or far future technology enables the expression and the processing of grief. The characters in the work experience loss: loss of a family member or a loss of identity. Validation Set additionally focuses on themes of the nature of consciousness, feelings of alienation, and what happens when the best of parental intentions go awry
Open Source Toolkit for Statistical Machine Translation: Factored Translation Models and Confusion Network Decoding
Women in Science: Surpassing Subtle and Overt Biases through Intervention Programs
This study discusses factors that keep women from entering science and technology, which include social stereotypes that they struggle against, lack of maternity leave and other basic human rights, and the climate that makes them leave research positions for administrative ones. We then describe intervention processes that have been successful in bringing the ratio of women close to parity, compare different minorities in the US, and also consider data from India, Western and Eastern Europe. We conjecture that programs that connect the different levels of education are needed in addition to hiring more women, providing them with basic human rights from when they begin their PhD onwards and promoting support networks for existing employees.
The authors of this paper hail from Sri Lanka, Romania, India, and the United States. We hold undergraduate and graduate degrees in physics or chemistry from the United States, India and Switzerland. Our conclusions are based on data that is publicly available, on data we have gathered, and on anecdotal evidence from our own experience
Women in Science: Surpassing Subtle and Overt Biases through Intervention Programs
This study discusses factors that keep women from entering science and technology, which include social stereotypes that they struggle against, lack of maternity leave and other basic human rights, and the climate that makes them leave research positions for administrative ones. We then describe intervention processes that have been successful in bringing the ratio of women close to parity, compare different minorities in the US, and also consider data from India, Western and Eastern Europe. We conjecture that programs that connect the different levels of education are needed in addition to hiring more women, providing them with basic human rights from when they begin their PhD onwards and promoting support networks for existing employees. The authors of this paper hail from Sri Lanka, Romania, India, and the United States. We hold undergraduate and graduate degrees in physics or chemistry from the United States, India and Switzerland. Our conclusions are based on data that is publicly available, on data we have gathered, and on anecdotal evidence from our own experience
Women in Science: Surpassing Subtle and Overt Biases through Intervention Programs
This study discusses factors that keep women from entering science and technology, which include social stereotypes that they struggle against, lack of maternity leave and other basic human rights, and the climate that makes them leave research positions for administrative ones. We then describe intervention processes that have been successful in bringing the ratio of women close to parity, compare different minorities in the US, and also consider data from India, Western and Eastern Europe. We conjecture that programs that connect the different levels of education are needed in addition to hiring more women, providing them with basic human rights from when they begin their PhD onwards and promoting support networks for existing employees. The authors of this paper hail from Sri Lanka, Romania, India, and the United States. We hold undergraduate and graduate degrees in physics or chemistry from the United States, India and Switzerland. Our conclusions are based on data that is publicly available, on data we have gathered, and on anecdotal evidence from our own experience