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Today's Topics:
1. SQUIRE a space-ground network exploring dark matter and other
beyond-Standard-Model phenomena' (Stephen Loosley)
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Message: 1
Date: Tue, 09 Dec 2025 21:28:24 +1030
From: Stephen Loosley <[email protected]>
To: "link" <[email protected]>
Subject: [LINK] SQUIRE a space-ground network exploring dark matter
and other beyond-Standard-Model phenomena'
Message-ID: <[email protected]>
Content-Type: text/plain; charset="UTF-8"
Scientists are turning Earth into a giant detector for hidden forces shaping
our Universe
Date: December 6, 2025
Source: Science China Press
https://www.sciencedaily.com/releases/2025/12/251205054737.htm
Summary:
SQUIRE aims to detect exotic spin-dependent interactions using quantum sensors
deployed in space, where speed and environmental conditions vastly improve
sensitivity.
Orbiting sensors tap into Earth?s enormous natural polarized spin source and
benefit from low-noise periodic signal modulation.
A robust prototype with advanced noise suppression and radiation-hardened
engineering now meets the requirements for space operation.
The long-term goal is a powerful space-ground network capable of exploring dark
matter and other beyond-Standard-Model phenomena.
Share:
FULL STORY: Space Quantum Sensors Hunt Hidden Forces
[Photo caption: A high-speed space-based quantum sensor network poised to
uncover new physics lurking in the cosmos. Credit: AI/ScienceDaily.com]
By placing ultra-sensitive quantum spin sensors in orbit, SQUIRE gains
orders-of-magnitude improvements in detecting exotic physics signals.
This approach lays the groundwork for a global and interplanetary sensing
system that could reveal hidden particles and forces.
Understanding SQUIRE and Its Space-Based Quantum Strategy
Exotic-boson-mediated interactions fall into 16 categories. Of these, 15 depend
on particle spin and 10 depend on relative velocity. These interactions can
produce small shifts in atomic energy levels, and quantum spin sensors detect
those shifts as pseudomagnetic fields. The SQUIRE mission intends to place such
sensors on space platforms, including the China Space Station, to look for
pseudomagnetic fields generated by exotic interactions between the sensors and
Earth's geoelectrons. By combining space access with quantum precision tools,
SQUIRE avoids a major limitation of ground experiments, which struggle to
increase both relative velocity and the total number of polarized spins at the
same time.
Why Low Earth Orbit Greatly Improves Sensitivity
Several features of the orbital environment provide strong advantages.
The China Space Station travels in low Earth orbit at 7.67 km/s relative to
Earth, nearly the first cosmic velocity and about 400 times faster than typical
moving sources used in laboratory tests.
Earth acts as an enormous natural source of polarized spins. Unpaired
geoelectrons within the mantle and crust, aligned by the geomagnetic field,
supply roughly 1042 polarized electrons, exceeding the capabilities of SmCo5
laboratory spin sources by approximately 1017.
Orbital motion turns exotic interaction signatures into periodic signals. For
the China Space Station (orbital period ~1.5 hours), this produces modulation
near 0.189 mHz, a region with lower intrinsic noise than DC measurement bands.
Projected Performance Gains in Orbit
With these space-enabled benefits, the SQUIRE concept allows exotic field
amplitudes to reach up to 20 pT even under strict current limits on coupling
constants. This is dramatically higher than the best terrestrial detection
threshold of 0.015 pT. For velocity-dependent interactions with force ranges
>10? m, the projected sensitivity improves by 6 to 7 orders of magnitude.
Building a Space-Ready Quantum Spin Sensor
Developing the prototype quantum sensor is essential for putting SQUIRE into
operation. The instrument must remain extremely sensitive and stable over long
periods while operating in a challenging orbital environment. In space, spin
sensors encounter three dominant sources of interference: variations in the
geomagnetic field, mechanical vibrations of the spacecraft, and cosmic
radiation.
Reducing Noise and Increasing Stability
To overcome these challenges, the SQUIRE team created a prototype using three
major innovations.
Dual Noble-Gas Spin Sensor: The device uses 129Xe and 131Xe isotopes with
opposite gyromagnetic ratios, which allows it to cancel shared magnetic noise
while remaining responsive to SSVI signals. This approach provides 104-fold
noise suppression. With multilayer magnetic shielding, geomagnetic disturbances
fall to the sub-femtotesla level.
Vibration Compensation Technology: A fiber-optic gyroscope tracks spacecraft
vibrations and enables active correction, bringing vibration noise to roughly
0.65 fT.
Radiation-Hardened Architecture: A 0.5 cm aluminum enclosure and triple modular
redundancy in its control electronics protect the system from cosmic rays. The
design can continue functioning even if two of the three modules fail, reducing
radiation-related interruptions to fewer than one per day.
On-Orbit Sensitivity and Scientific Readiness
By combining these technologies, the prototype achieves a single-shot
sensitivity of 4.3 fT @ 1165 s, which is well matched to detecting SSVI signals
that follow the 1.5-hour orbital period. This capability establishes a strong
technological basis for precision dark matter searches conducted directly in
orbit.
Expanding Toward a Space-Ground Quantum Sensing Network
Quantum spin sensors aboard the China Space Station can do far more than search
for exotic interactions. SQUIRE proposes a "space-ground integrated" quantum
sensing network that links orbital detectors with those on Earth, enabling far
greater sensitivity across many dark matter models and other
beyond-Standard-Model possibilities. These include additional exotic
interactions, Axion halos, and CPT violation studies.
Future Opportunities Across the Solar System
The high-speed motion of orbiting sensors increases the coupling between axion
halos and nucleon spins, producing a tenfold sensitivity improvement compared
with Earth-based dark matter searches. As China expands deeper into the solar
system, the SQUIRE approach may eventually employ distant planets such as
Jupiter and Saturn (e.g., planets rich in polarized particles) as large natural
spin sources. This long-term vision opens the door to exploring physics across
much broader cosmic scales.
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