Approximately 80% of the universe's matter is dark, eluding direct observation but detectable through its gravitational effects. Despite ongoing efforts, these dark matter particles remain unseen.

Scientists from Lancaster University, the University of Oxford, and Royal Holloway, University of London are deploying the most sensitive dark matter detectors ever constructed, showcased in "A Quantum View of the Invisible Universe" at the Royal Society's Summer Science Exhibition from July 2-7, 2024.

The research team includes Dr. Michael Thompson, Professor Edward Laird, Dr. Dmitry Zmeev, and Dr. Samuli Autti from Lancaster, Professor Jocelyn Monroe from Oxford, and Professor Andrew Casey from Royal Holloway.

EPSRC Fellow Dr. Autti commented, "We are using quantum technologies at ultra-low temperatures to build the most sensitive detectors to date. The goal is to observe this mysterious matter directly in the laboratory and solve one of the greatest enigmas in science."

While indirect evidence suggests dark matter density in the galaxy, the mass and interactions of these particles with ordinary atoms remain unknown. Particle physics points to two primary dark matter candidates: particles with extremely weak interactions and very light wave-like particles called axions. The team is developing experiments to search for both.

Particles with ultra-weak interactions might be detectable through collisions with ordinary matter, dependent on the mass of the dark matter particles. Many searches focus on particles with masses between five and 1,000 times that of a hydrogen atom. However, lighter candidates might have been overlooked.

The Quantum Enhanced Superfluid Technologies for Dark Matter and Cosmology (QUEST-DMC) team seeks to detect collisions with dark matter particles weighing between 0.01 to a few hydrogen atoms. Their detector, made of superfluid helium-3 and equipped with superconducting quantum amplifiers, aims for unprecedented sensitivity.

For axions, incredibly light particles more abundant than those with weak interactions, detection is different. Axions, decaying in a magnetic field, produce an electrical signal measurable with highly precise quantum amplifiers. The Quantum Sensors for the Hidden Sector (QSHS) team is creating these amplifiers to detect axion signals.

The exhibition features interactive displays to make the unseen observable. Demonstrations include a gyroscope simulating unseen angular momentum, transparent marbles in liquid to illustrate invisible masses, and a light-up dilution refrigerator showcasing ultra-low temperatures. Visitors can experiment with model detectors for dark matter and axions.

Cosmologist Carlos Frenk, Fellow of the Royal Society and Chair of the Public Engagement Committee, stated, "Science is vital in helping us understand the world we live in - past, present and future. I urge visitors of all ages to come along with an open mind, curiosity and enthusiasm and celebrate incredible scientific achievements that are benefiting us all."

This research is supported by the UKRI Quantum Technologies for Fundamental Physics programme.

Research Report:QUEST-DMC: Background Modelling and Resulting Heat Deposit for a Superfluid Helium-3 Bolometer

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