Lately, I have been thinking about a lot of different and fun topics.
Here is a brief overview of them in order of what I have been thinking about the most.
Building a Cryogenic Coating Test Facility for LIGO Voyager
LIGO Voyager is a proposed design for next generation interferometers that will improve the sensitivity LIGO by a factor of 10. That is a big deal if you want to look further in the universe as each improvement of sensitivity increases by a factor of 3. In other words, improve the detector by 10 then you can increase the volume where you can detect gravitational waves by 1,000.
This interferometer design uses silicon as the main optic and moves away from using fused silica (fancy glass). The intention is to then cool these core optics down to 123K. The benefits of moving in this direction are that silicon has much better properties - at 123K, the length of silicon does change very much for a change in temperature also it's mechanical properties do not get worse as you get cold (something that happens with fused silica). This design will also use radiative cooling rather than conductive cooling to reduce the vibrational effects from the cooling mechanism itself.
The central question that our research addresses is - what types of coatings will be used on these cold silicon optics? That's where Aaron Markowitz and I come in. What we have built is a cryogenic test facility to quantify the effects of different coatings deposited on silicon. Our experiment cools down tests disks, excites their resonant modes, and reads everything out with an optical lever. We use the ring-down of each resonated mode to quantify the effects of deposited coatings. If they are good quality coatings then this ring-down measurement will be high ( and take a long time). If they are not so good coatings then we will state that these are not necessarily the direction that we want to take. Our cryostat is up and running and we will likely get our next set of good coating measurements very soon.
Colleagues : Aaron Markowitz (Caltech), Rana Adhikari ( Caltech ), Jordan Kemp ( University of Chicago), Mariia Matiushechkina (Moscow State University), Mandy Cheung (Pasadena City College)
Searching for Cosmic Strings with the Holometer
We began thinking about other interesting astrophysical constraints we could make using the Holometer dataset. One neat object of interest are cosmic strings, which are cracks in space-time formed in the very early universe. These topological defects could turn in to oscillating loops that will produce gravitational waves. A neat thing about the Holometer is that we have sensitive data in a frequency range that no one else has explored. We hope to put out results of this search within the next few months. Stay tuned!
Colleagues : Jeronimo Martinez (University of Chicago)
Seismic Cloaking for LIGO
Trees are incredibly amazing and we are going to explore how trees could potentially shield the LIGO detectors from seismic waves. In the seismology world, there has been some recent work on how you could use a forest of trees to shield from propagating seismic waves. In our research project, we are going to explore if having a forest surrounding the LIGO detectors would actually help. The LIGO detectors are so sensitive that whenever there is a propagating surface wave, the gravitational effects of different lumps of dirt going up and down (from this wave) affect the sensitivity of the detectors. We will need to quantify what frequencies a potential forest could shield the LIGO detectors from and make sure that it won't become worse in another frequency range.
Colleagues : Ka'ila Nathaniel (Virginia Tech ) and Rana Adhikari (Caltech)
Exploring the solar neighborhood with LISA
An exciting thing to think about is whether you could measure the gravitational wave signature from exoplanets in a space-based gravitational wave detector like LISA. We started thinking about this and will hopefully come up with some answers about what the exoplanet population would need to look like in order to be measured in LISA. We have also started to ask the question about all the stellar binaries in our neighborhood. When we are done then we could say something about the gravitational waves signatures of these systems.
Colleagues : Yilen Gomez Maqueo Chew (UNAM), Katie Brevik (Northwestern), Kelly Holley-Bockelmann (Vanderbilt University), Bill Gabella (Vanderbilt University)
Experimental Constraints on Quantum Cosmology
I hang out with Sean Carroll's quantum cosmology group. We get together once a week and discuss current topics in the theoretical world addressing this union between quantum mechanics and general relativity. At the moment, I mostly ask questions "How can we measure that?" or "Could this be an observational signature of that?" This is helping me develop the skillset to take theoretical arguments and think about building experiments around them. I see this as important stepping stones along my lifelong quest to measure signatures of dark energy in the lab.
Colleagues : Sean Carroll (Caltech), Abby Crites (Caltech), and the cool kids who come to Sean's group meeting
Image credits : Cold Cryostat - Brittany Kamai ; Cosmic String art - AngeloVentura ; Forest - American Heritage ; LISA - main ESA website ; Cool colorful black hole looking things - Brittany Kamai courtesy of a cool art project done here at Caltech in collaboration with Rana and visiting friends