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Abstract:
This focus group will examine the interface between numerical relativity and gravitational waves. What are the most important problems and the most promising avenues for progress over the next five years?
Archived Talks from this Workshop:
Dick Bond: http://www.cita.utoronto.ca/TALKS/Bond-Aug28-07.pdf
Alessandra Buonanno: http://www.cita.utoronto.ca/TALKS/Buonanno-Aug30-07.pdf
Michael Kesden: http://www.cita.utoronto.ca/TALKS/Kesden-Aug29-07.pdf
Larry Kidder: http://www.cita.utoronto.ca/TALKS/Kidder-Aug30-07.pdf
Lev Kofman: http://www.cita.utoronto.ca/TALKS/Kofman-Aug31-07.pdf
Luis Lehner (general talk): http://www.cita.utoronto.ca/TALKS/Lehner-Aug28-07.pdf
Luis Lehner (technical talk): http://www.cita.utoronto.ca/TALKS/Lehner-Aug29-07.pdf
Harald Pfeiffer (general talk): http://www.cita.utoronto.ca/TALKS/Pfeiffer-Aug28-07.pdf
Harald Pfeiffer (technical talk): http://www.cita.utoronto.ca/TALKS/Pfeiffer-Aug28-07.pdf
Eric Poisson: http://www.cita.utoronto.ca/TALKS/Poisson-Aug31-07.pdf
Invited Participants:
Alessandra Buonanno (Maryland)
Larry Kidder (Cornell)
Luis Lehner (Louisiana State)
Harald Pfeiffer (Caltech)
Eric Poisson (Guelph)
Bill Unruh (UBC)
Revised Schedule:
Tuesday:
10:00-11:00am Harald Pfeiffer general talk: "Numerical simulations of binary
black holes" (abstract below)
11:00-11:30 coffee
11:30-12:30 Lehner general talk: "Beyond binary black holes in numerical
relativity" (abstract below)
lunch
2:00-3:00 Bond/Kofman/Prokushkin/Vaudrevange/Boyle...gravitational waves
from inflation (especially roulette inflation?)
3:00-? Discussion of numerical GR. Potential of different numerical
techniques: next 10 years. Strengths and weaknesses of various algorithms
(pseudo-spectral vs. traditional finite-difference techniques, puncture
method vs. excision, etc.). What problems in numerical GR are computationally
impossible now, but will (or could) be possible in 5 or 10 years?
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Wednesday:
10:00-11:00: Lehner technical talk (TBA)
11-11:30 coffee
11:30-12:30 Pfeiffer technical talk: "Spectral methods for Einstein's
equations" (abstract below)
lunch
2:00-3:00 Kesden: "Binary black hole merger: symmetry and the spin expansion"
3:00-? What fundamental physics questions can numerical GR hope to answer
or shed light on? What is a physicists' wish list for numerical GR?
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Thursday:
10-11am Buonanno: "Interfacing analytical and numerical relativity: binary
black-hole coalescence" (part 1)
11-11:30 coffee
11:30-12:30 Kidder (TBA)
lunch
2:00-3:00pm Buonanno: "Interfacing analytical and numerical relativity:
binary black-hole coalescence" (part 2)
3:00-? Discussion: Simulations of black hole merger -- even just the final
few orbits -- are very computationally expensive. How can we maximize the
scientific payoff from a relatively small number of well-chosen simulations?
i.e. the interface between data analysis for LIGO/VIRGO/LISA etc. and
numerical relativity waveforms
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Friday:
10:00-11:00am Poisson: black holes in tidal environments
11:00-11:30 coffee
11:30-12:30 Discussion: How can numerical GR be tested astrophysically? What
will it teach us about astrophysics (including gravitational-wave
astrophysics). What astrophysical (non-GR) effects must still be included to
make the simulations realistic, what can they teach us astrophysically, how
can they be tested astrophysically?
lunch
2:00-3:00 Kofman/Dufaux: Gravitational waves from preheating after inflation
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Abstracts for Luis Lehner and Harald Pfeiffer's talks:
Numerical simulations of binary black holes
Harald Pfeiffer (general talk)
Binary black holes are one of the prime sources of gravitational waves
for current and future gravitational wave detectors. Numerical
relativity plays a critical role for such gravitational wave
observations, both for construction of search templates and
characterization of detected events. Two years ago a revolution
occured in numerical relativity: After several decades, simulations of
orbiting and merging black holes became feasible. Leading up to these
simulations, it was necessary to understand several unique features of
Einstein's equations and to devise ways to deal with them:
Singularities inside black holes; coordinate freedom; constraint
violating modes; construction of astrophysically realistic initial
data. In addition, the application to gravitational wave observations
requires extraordinary high numerical accuracy, pushing traditional
computational techniques to the limit and fostering adoption of new
techniques like spectral methods. This talk aims to convey the flavor
of some of these issues and present the key ideas for their solution.
Of course, I will also present some of the spectacular recent results
of numerical relativity.
Beyond binary black holes in numerical relativity
Luis Lehner (general talk)
While many efforts have been concentrated towards
simulating binary black hole problems a number of
other systems require of numerical simulations as well.
The reasons for understsanding these ``other'' systems
follow both pragmatic and/or fundamental reasons.
This talk will present an overview of some representative
cases, describe key ingredients of the implementation
and highlight how simulations have not only played
a key role in the understanding of the problem but also spurred
further questions.
Spectral methods for Einstein's equations
Harald Pfeiffer (technical talk)
Simulations of black hole spacetimes have traditionally used finite
difference methods and have achieved remarkable success with these
techniques. Because gravitational wave data analysis requires a large
number of simulations with exquisite numerical accuracy, the
Cornell/Caltech group has focused their efforts on an alternative
technique: Multi-domain spectral methods promises spectacular accuracy
modest computational cost. In this talk, I will explain why spectral
methods are ideal for black hole simulations. I will describe in
detail the initial value problem of Einstein's equations, a field now
dominated by spectral methods. And I will briefly present our
evolution code, and show how to use evolutions to construct initial
data with desired properties, like vanishingly small eccentricity.
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