LBNL Physics Division Research Progress Meetings

Speaker: Chelsea Bartram (Stanford) - Title: Dialing into the Dark Matter with Novel Quantum Techniques
2026-05-28 16:00 - 17:00 UTC
Research Progress Meeting
Date: May 28, 2026
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Chelsea Bartram (Stanford)
Title: Dialing into the Dark Matter with Novel Quantum Techniques
Abstract: The QCD axion is a well-motivated dark matter candidate that could solve the strong CP problem. The axion haloscope, which leverages the inverse Primakoff effect, renders the QCD axion ‘visible’ — if it exists. Still, finding the QCD axion is no trivial matter. The QCD axion could span up to 13 orders of magnitude in mass space. Searches at higher masses suffer from the problem of scaling the detectors to smaller volumes, and thus, smaller signal powers. Searches at lower masses suffer from the need to achieve sensitivity to much smaller axion-photon couplings. I will discuss major efforts to cover the axion parameter space, including the Axion Dark Matter eXperiment (ADMX) and DMRadio searches. Further, I will explain some proposed enabling technologies for accelerated searches. It is clear new direct detection techniques are needed to cover such an expansive parameter space. In this talk, I present a novel technique for improved impedance matching to wave-like dark matter. It is known that an RLC resonator is well-suited to axion direct detection. We propose an alternative circuit that replaces the capacitance with a ‘negative inductance’ to cancel reactance over a wider range of frequencies. Using the unique properties of a Josephson junction, we show that we can achieve broadband reactance cancellation via simulation. I will discuss our preliminary understanding of the stability and operation of the circuit. To our knowledge, this circuit represents the first implementation of a Josephson junction in a non-Foster circuit, which uses an active component to evade the Bode-Fano limits on the bandwidth of a match. The Josephson junction must be operated in a cryogenic environment; thus, its implementation in a non-Foster circuit is well-suited for axion searches that require low physical temperatures.
https://lbnl.zoom.us/j/98854322464?pwd=[REDACTED]
Meeting ID: 988 5432 2464

Passcode: [REDACTED]
