Directional search for light dark matter with quantum sensors

Abstract

The presence of dark matter (DM) stands as one of the most compelling indications of new physics in particle physics. Typically, the detection of wave-like DM involves quantum sensors, such as qubits or cavities. The phase of the sensors is usually discarded as the value of the phase itself is not physically meaningful. However, the difference of the phase between the sensors contains the information of the velocity and direction of the DM wind. We propose a measurement protocol to extract this information from the sensors using quantum states. Our method does not require specific experimental setups and can be applied to any type of DM detector as long as the data from the detectors can be taken quantum mechanically. We also show that our method does not spoil the sensitivity of the DM detectors and is superior to the classical method based on the correlations of the DM signals between the detectors.

Figures (3)

• Figure 1: Left: The blue solid (dotted) line shows value of $\overline{M}$ as a function of $m v_0 \Delta r$ using numerical integration (analytic approximation) (left axis). The dashed lines show the number of measurements needed to achieve $v_{0}/\delta v_{0} = 3$ (right axis). The orange, green, and red lines correspond to the noise rate, $c=0, 2\epsilon^2\tau^2$, and $20 \epsilon^2\tau^2$, respectively. Right: The solid lines show the value of $\overline{M}$ as a function of $\theta$, the angle between $\Delta r$ and the direction to the galactic center within the galactic plane (left axis). The blue (purple) line corresponds to the case with (without) the annual modulation of the DM wind. The dashed lines show the number of measurements needed to achieve $v_{\text{obs},x}/\delta v_{\text{obs},x} = 3$ (right axis). The color means the same as the left figure. (See Ref. Fukuda_dataset2025 for the dataset.)
• Figure 2: Quantum circuit for $P_1$ measurement.
• Figure 3: Quantum circuit for $M$ measurement.