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Jeff Dror

Jeff DrorAssistant Professor

Ph.D., Cornell University (2017)

Research Group

High Energy Theory in the Institute for Fundamental Theory

Research Interest

Understanding the evolution of the Universe requires finding particles ejected during different epochs. We have already detected two classes of such cosmic fossils: microwave photons and light nuclei. While we have learned a great deal from these discoveries, they have left significant gaps in our knowledge of the cosmic history since the Big Bang. My research interest focuses on detecting new cosmic fossils in the form of axions and gravitational waves.

The axion is a so-far hypothetical particle predicted by many theories beyond the Standard Model. It can be a relic from the early Universe and make up a non-relativistic fluid (dark matter) or a relativistic fluid (dark radiation) surrounding us today. In my research, I propose experimental searches to discover either possibility.

Events in the early Universe, such as supermassive black hole mergers, cosmic phase transitions, and inflation, are known to produce gravitational waves across a wide range of frequencies. In my research, I focus on gravitational wave detection in the nHz regime (10-1000 billion times lower frequency than those detected by the LIGO experiment). The most promising way to detect such gravitational waves is by tracking the arrival times of light pulses from nearby stars known as pulsars. There is an ongoing international effort to detect a signal in the nHz range, and my work focuses on extending their sensitivity to the pHz-nHz regime. This requires developing new ways to analyze the pulsar light data.

Selected Publications

“Searching For Stochastic Gravitational Waves Below a Nanohertz” [2304.13042]
“Using Pulsar Parameter Drifts to Detect Sub-Nanohertz Gravitational Waves” [2212.09751]
“New Insights Into Axion-Lepton Interactions”[2209.00665]
“On the Sensitivity of Spin-Precession Axion Experiments” [2210.06481]
“Cosmic axion Background” [2101.09287]

2079 NPB