Research Experiences

Lyman α forrest with Scatter Transform

Advisor: Professor Simeon Bird

UC Riverside, 2023 (This work has been submitted for publication in physical review letters. Preprint version of our manuscript can be found at https://arxiv.org/pdf/2310.06010.pdf. )

Upcoming experiments, such as the Dark Energy Spectroscopic Instrument (DESI), and the WEAVE-QSO surveys are set to push the boundaries even further by measuring the flux power spectrum for Lyman α forrest at smaller scales and higher redshifts, aiming for an accuracy of a few percent. To take full advantage of these ambitious observations, we need better extract more cosmological information. The conventional approach employing a twopoint correlation function (or power spectrum) as a summary statistic proves efficient for larger scales, as the density field exhibits near-Gaussian isotropy on linear scales. However, we lose information on smaller scales if we use two-point summary statistics as the field is highly nonGaussian. So, we use scatter transform which allows us to extract Non-gaussian information at different scales- including at small scales. We generate fisher matrix to compare how tighly can scatter transform constrain cosmological parameters compared to power spectra.

Fine-Structure Constant Variation

Advisor: Professor Daniel Grin, Haverford College.

(This work has been submitted for publication and can be found at https://arxiv.org/pdf/2307.06768.pdf. I wrote my undergraduate thesis based on this work titled Fine Structure Constant Variation in 2022. I also received AIP SPS Outstanding Undergraduate Award for this work in 2022.)

In some extensions of the standard model of particle physics, the values of the fundamental coupling constants could vary in space and time. I explored variation of the fine structure constant, α across time and space. The notion of α variation was first introduced by Paul Dirac in 1937. While controversial, quasar absorption spectra and a number of high energy physics theories showed a possibility of alpha variation. However, alpha variation has not been tested using concrete predictions from CMB. So, we tested alpha variation using CMB anisotropies from Planck 2018 data in: Bekenstein-Sandvik-BarrowMagueijo (BSBM) model which is a quintessence-like model with coupling to a scalar field that evolves as the universe expands driving evolution in the fundamental electric charge, and the Runaway Dilaton which is a string theory model. The runaway dilaton model predicts the existence of a scalar field that approaches a strong coupling and gives quantitative estimates for the violation of the equivalence principle that allow physical constants to vary. variations in e are coupled to the matter density through a factor ζ/ω, which is related to electromagnetic contributions to nucleon masses, and the energy scale of new physics. We use principle components of Planck 2018 data to constraint parameters of the BSBM model forecast which values of the parameters upcoming Simon Observatory experiment will be sensitive to.

Mosquito Species detection using neural network from wingbeat data

Team: Project Premonition

Summer 2022, Microsoft Research, WA.

Project premonition aims to biologically map diseases using blood collected by mosquitos. A big part of it is independent on being able to detect particular species of mosquitos and extending the project for other insects. Depending on the size of the mosquito and their corresponding species Mosquioto wingbeats are supposed to vary. However, implementing this approach presents significant challenges due to the sensitivity of the optical sensors employed in the project. These sensors are exceptionally responsive to external light, and therefore distinguishing between environmental noise changes and species-specific wingbeat changes can prove difficult.

I developed a noise-filtering system and designed a time series-based neural network for accurate mosquito species classification which outperformed the previously used classifier. I then corroborated the classification results with the ecological characteristics associated with each mosquito species, thereby confirming the validity of the system.

Selection Biases in X-Ray cavities

Advisor: Professor Michael McDonald

Summer 2021, Massachusetts Institute of Technology, MA.

X-ray observations have shown that the wholesale cooling of the universe is being offset by mechanical heating from active galactic nuclei(AGN). Feedback and heating from AGN are considered a prime candidate for solving the “cooling flow” problem in the hot gas of galaxy clusters. Recent observations using Chandra telescope has produced detection of X-ray surface brightness depressions known as “cavities” or “bubbles” in many of these systems, interpreted as buoyantly rising bubbles created by AGN outbursts. Studies of such cavities in clusters suggest that the outburst energy required to inflate these cavities would be sufficient to balance cooling. The pressure from these cavities have a one-to-one correlation with the luminosity of the clusters. We have created simulations by imagining bubbles by varying their radii and distance from the AGN center using different theoretical models and experimental data of X-ray cavities. We then looked at their pressure and corresponding luminosity of the clusters and found a similar correlation which implies that correlation is rather a property of the gas cluster. So, the objects that we observe as cavities might be just numerical noise in the telescope data as the pressure-luminosity one-to-one correlation is not a cavity specific property. We have also observed that scatter is dependent on the bubble geometry. However, we ddidn't recover the observational relation. We predict that the distance-radius correlation seen in previous literature was artificially tight.

(More details on this work can be found on this poster presented at MIT Summer Research Symposium.

Computing Lifshitz Field Theory Correlation Functions Using the AdS/CFT Correspondence

Advisor: Professor Michael Schulz

Summer 2021, Bryn Mawr College, PA.

We used Anti-de Sitter spacetime/Conformal Field Theory (AdS/CFT) correspondence to determine quantum field theory correlation functions— expectation values of products of fields–—in two field theories, by performing a calculation in the dual gravity theory. I.e., we compute the correlation functions holographically. The first field theory is the canonical one. We solve the KleinGordon equation in Anti-de Sitter spacetime or asymptotically so which gives us two independent solutions with undetermined coefficients. The path integral depends on these coefficients, which correspond to a choice of boundary condition on the AdS side and a choice of sources on the field theory side. On the field theory side, the correlation functions coincide with derivatives of the path integral with respect to the sources. We perform the corresponding dual gravity calculation. After completing the calculation for the canonical AdS/CFT setting, we perform the analogous computation for a novel field theory of interest in condensed matter physics, which possesses a Lifshitz multicritical point.

(More details on this work can be found on this poster poster presented at Summer Science Research Symposium, Bryn Mawr College.