International Center for Quantum-field Measurement Systems for Studies of the Universe and Particles

Scientists have established a new framework for detecting dark matter utilising quantum sensors with unprecedented sensitivity. Muping Chen and colleagues from the International Centre for Quantum-field Measurement Systems for Studies of the Universe and Particles (QUP), Japan, Kavli Institute, The University of Tokyo, Graduate University, Theory Centre, and 1 other institutions present a halo-independent method for sub-GeV dark matter direct detection, employing sensors capable of sub-eV energy thresholds. This approach enables access to low dark matter velocities and investigation of deviations from the Standard Halo Model, a task proving challenging for conventional direct detection experiments. By expressing event rates through a universal halo function, the team demonstrates the potential to map the local dark matter velocity distribution using technologies like TES (Al) and MKID (TiN) sensors, opening a key pathway for understanding this elusive substance.

Low velocity dark matter detection via quantum sensor velocity reconstruction

The Centre for Quantum-field Measurement Systems for Studies of the Universe and Particles (QUP) has achieved a sensitivity threshold of 0.1 electron volts, representing a substantial improvement over previous dark matter detection methods typically limited to energies above 1 electron volt. This leap in sensitivity unlocks access to the low velocity regions of dark matter’s phase space, previously inaccessible to conventional experiments which struggle with the exceedingly weak interactions expected from low-mass dark matter particles. The motivation for pursuing such low-mass dark matter candidates stems from theoretical models attempting to address inconsistencies within the Standard Model of particle physics and provide explanations for observed astrophysical phenomena, such as galactic rotation curves and the cosmic microwave background. A halo-independent framework was developed to reconstruct the local dark matter velocity distribution directly from detector data, circumventing reliance on assumptions about galactic dark matter distribution by utilising transition edge sensors and microwave kinetic inductance detectors. Traditional dark matter searches often rely heavily on the Standard Halo Model, which posits a spherically symmetric, isothermal distribution of dark matter surrounding our galaxy. However, this model may not accurately reflect the true distribution, introducing uncertainties into the interpretation of experimental results.

At QUP, quantum sensors differentiate between dark matter particle velocities, utilising differing material responses in transition edge sensors (TES) and microwave kinetic inductance detectors (MKID). TES sensors, superconducting devices operated at extremely low temperatures, measure energy deposited by incident particles with exceptional precision, boasting an energy resolution of 0.036 electron volts. This high resolution arises from the sharp transition in resistance exhibited by the sensor as it switches between superconducting and normal states. MKID sensors, also superconducting, detect energy through changes in the resonant frequency of a microwave circuit, achieving an energy resolution of 0.13 electron volts. These sensors probe complementary regions of the dark matter velocity distribution due to their differing sensitivities and detection mechanisms. Mock data analysis revealed successful reconstruction of assumed halo functions, effectively mapping the expected distribution of dark matter velocities by analysing the rate of dark matter scattering events. The reconstruction process involves sophisticated statistical analysis techniques to disentangle the contributions from various velocity components and account for detector effects. Currently, the accuracy of this reconstruction is limited by simplified assumptions regarding detector efficiency and energy resolution, meaning practical application requires further refinement of these parameters and a more detailed understanding of sensor performance, including modelling of noise sources and calibration procedures.

Reconstructing local dark matter velocities with quantum sensors bypasses galactic halo modelling

A pioneering new technique for detecting dark matter is underway, moving beyond confirming its existence to mapping its distribution within our galaxy. This framework promises to reconstruct the local velocity distribution of dark matter directly from experimental data, a feat previously hampered by reliance on assumptions about the overall galactic halo. By focusing on this reconstruction, strong conclusions can be drawn even with an incomplete understanding of the galaxy’s structure, offering a significant advantage over traditional methods. The ability to constrain the local dark matter velocity distribution independently of galactic halo modelling is crucial for validating theoretical models and improving our understanding of dark matter’s fundamental properties.

The researchers at the Centre for Quantum-field Measurement Systems for Studies of the Universe and Particles (QUP) have established a method for detecting dark matter that does not rely on assumptions about its galactic distribution. Accessing low energy interactions, below 0.1 electron volts, this approach probes previously inaccessible regions of dark matter’s phase space and potentially reveals deviations from the Standard Halo Model. The Standard Halo Model assumes a Maxwell-Boltzmann velocity distribution for dark matter particles, but alternative models predict more complex distributions with features such as streams or substructures. Consequently, investigation of dark matter properties is now possible in a new way, potentially uncovering subtle features in its velocity distribution. The framework expresses the dark matter scattering event rate in terms of a detector and particle model-dependent response function, and a universal halo function common to all experiments. This universality is achieved by factoring out the detector-specific details, allowing for a direct comparison of results from different experiments and a more robust determination of the local dark matter velocity distribution. The implications of this work extend beyond mapping the dark matter velocity distribution; it also provides a powerful tool for testing the validity of different dark matter models and searching for new physics beyond the Standard Model.

The research team developed a new framework for detecting dark matter that successfully separates detector responses from the underlying distribution of dark matter particles. This is important because it allows scientists to map the local velocity distribution of dark matter without relying on assumptions about the overall galactic halo. Using quantum sensors capable of detecting energies below 0.1 electron volts, the method reconstructs the halo function from experimental data, as demonstrated with mock data from several benchmark models. The framework utilises both TES (Al) and MKID (TiN) sensors to probe different aspects of the dark matter velocity distribution.